Bruce K. Dixon

CHICAGO — Dual-source computed tomography significantly reduces radiation exposure to patients undergoing heart scans, and eliminates the need for heart-slowing medications, according to a study presented at the annual meeting of the Radiological Society of North America.

Improved temporal resolution with dual-source CT improves diagnostic quality by significantly reducing cardiac motion artifacts, obviating the need for β-blockade, said Dr. U. Joseph Schoepf.

In addition, more effective ECG pulsing techniques and faster scan times available with dual-source CT (DSCT) significantly decrease radiation dose by an average of 10%, compared with conventional 64-slice CT, Dr. Schoepf said in an interview.

“Dual-source CT has built-in features that allow the operator to accurately tailor radiation dose to each patient,” said Dr. Schoepf, associate professor of radiology and medicine at the Medical University of South Carolina (MUSC) in Charleston.

In this study, the first 30 patients who underwent CT angiography with a DSCT scanner (SOMATOM Definition, Siemens Medical Solutions) were compared with the most recent 30 patients to undergo 64-slice CT angiography at MUSC.

“With the DSCT group, we were at the beginning of our learning curve, so by now we're even more facile in using the dual scanner than we were with the study patients,” Dr. Schoepf explained.

A fixed temporal resolution of 83 milliseconds, heart-rate adaptive pitch, and ECG pulsing were used with the DSCT in all cases. Temporal resolution at 64-slice CT was 165 milliseconds at a fixed pitch of 0.2.

With both scanners, the gantry rotation time was 330 milliseconds, collimation was 0.6 millimeters, and the injection protocol was triphasic.

A radiologist and a cardiologist who were blinded to the scanner type evaluated the coronary arteries for motion artifact using the American Heart Association segment model. Patient heart rate, radiation dose, and use of β-blockers were recorded.

“With the previous generation scanner, we still had to use β-blockers to slow heart rate to achieve good images,” Dr. Schoepf said in an interview. “We quickly learned that medications were not necessary with the DS scanner because of the faster shutter speed and better temporal resolution.”

The abandonment of ?-blockade simplifies procedural logistics, he said, explaining that the typical intravenous protocol requires having a nurse available and increases scan time because the drug is administered while the patient occupies the scanner table. “And it's always better to avoid giving drugs when you can,” he added.

The average computed tomography dose index (fundamental radiation dose parameter used in CT) volumes were 61 milligray (mGy) for patients aged 35–72 years and 53 mGy for patients aged 21–89 years, respectively (P < .001).

The average heart rates were 64 beats per minute among the control group and 73 beats per minute among those imaged with the dual scanner. β-Blockers were used in 12 of the 30 patients scanned with 64-slice CT; none were used in the DSCT group.

Cardiac motion artifacts were observed in 24% of coronary segments in 64-slice CT patients, compared with 9% of segments in the DSCT arm. In each group, data sets were completely void of motion artifacts in 3 of 30 and 12 of 30 patients, respectively.

“Overall, the diagnostic quality was better in the DSCT group despite the faster heart rates,” said Dr. Schoepf, who disclosed that he is a consultant to and has received research support from Siemens Medical Solutions and the imaging contrast divisions of Bayer, GE Healthcare, and Bracco Diagnostics. However, no outside funding was used for the current study or the scanners used in it, he said.

“With another step in the evolution of medical imaging, we're closing the gap from invasive to noninvasive diagnostic catheterization and getting to the point of being able to get the same diagnostic information, particularly for excluding coronary artery disease,” Dr. Schoepf said. “But the investment of around &dollar;2.6 million for a dual-source CT probably is only worth it if you want to exploit the particular capabilities of this device, which include the dedicated cardiac, vascular, and dual-energy applications.”

The SOMATOM Definition has been available in the United States since early 2006.

DSCT (right) of the pulmonary vein shows clearer delineation of all segments, compared with single-source 64-slice CT (left). Photos courtesy Dr. U. Joseph Schoepf

CHICAGO — Dual-source computed tomography significantly reduces radiation exposure to patients undergoing heart scans, and eliminates the need for heart-slowing medications, according to a study presented at the annual meeting of the Radiological Society of North America.

Improved temporal resolution with dual-source CT improves diagnostic quality by significantly reducing cardiac motion artifacts, obviating the need for β-blockade, said Dr. U. Joseph Schoepf.

In addition, more effective ECG pulsing techniques and faster scan times available with dual-source CT (DSCT) significantly decrease radiation dose by an average of 10%, compared with conventional 64-slice CT, Dr. Schoepf said in an interview.

“Dual-source CT has built-in features that allow the operator to accurately tailor radiation dose to each patient,” said Dr. Schoepf, associate professor of radiology and medicine at the Medical University of South Carolina (MUSC) in Charleston.

In this study, the first 30 patients who underwent CT angiography with a DSCT scanner (SOMATOM Definition, Siemens Medical Solutions) were compared with the most recent 30 patients to undergo 64-slice CT angiography at MUSC.

“With the DSCT group, we were at the beginning of our learning curve, so by now we're even more facile in using the dual scanner than we were with the study patients,” Dr. Schoepf explained.

A fixed temporal resolution of 83 milliseconds, heart-rate adaptive pitch, and ECG pulsing were used with the DSCT in all cases. Temporal resolution at 64-slice CT was 165 milliseconds at a fixed pitch of 0.2.

With both scanners, the gantry rotation time was 330 milliseconds, collimation was 0.6 millimeters, and the injection protocol was triphasic.

A radiologist and a cardiologist who were blinded to the scanner type evaluated the coronary arteries for motion artifact using the American Heart Association segment model. Patient heart rate, radiation dose, and use of β-blockers were recorded.

“With the previous generation scanner, we still had to use β-blockers to slow heart rate to achieve good images,” Dr. Schoepf said in an interview. “We quickly learned that medications were not necessary with the DS scanner because of the faster shutter speed and better temporal resolution.”

The abandonment of ?-blockade simplifies procedural logistics, he said, explaining that the typical intravenous protocol requires having a nurse available and increases scan time because the drug is administered while the patient occupies the scanner table. “And it's always better to avoid giving drugs when you can,” he added.

The average computed tomography dose index (fundamental radiation dose parameter used in CT) volumes were 61 milligray (mGy) for patients aged 35–72 years and 53 mGy for patients aged 21–89 years, respectively (P < .001).

The average heart rates were 64 beats per minute among the control group and 73 beats per minute among those imaged with the dual scanner. β-Blockers were used in 12 of the 30 patients scanned with 64-slice CT; none were used in the DSCT group.

Cardiac motion artifacts were observed in 24% of coronary segments in 64-slice CT patients, compared with 9% of segments in the DSCT arm. In each group, data sets were completely void of motion artifacts in 3 of 30 and 12 of 30 patients, respectively.

“Overall, the diagnostic quality was better in the DSCT group despite the faster heart rates,” said Dr. Schoepf, who disclosed that he is a consultant to and has received research support from Siemens Medical Solutions and the imaging contrast divisions of Bayer, GE Healthcare, and Bracco Diagnostics. However, no outside funding was used for the current study or the scanners used in it, he said.

“With another step in the evolution of medical imaging, we're closing the gap from invasive to noninvasive diagnostic catheterization and getting to the point of being able to get the same diagnostic information, particularly for excluding coronary artery disease,” Dr. Schoepf said. “But the investment of around &dollar;2.6 million for a dual-source CT probably is only worth it if you want to exploit the particular capabilities of this device, which include the dedicated cardiac, vascular, and dual-energy applications.”

The SOMATOM Definition has been available in the United States since early 2006.

DSCT (right) of the pulmonary vein shows clearer delineation of all segments, compared with single-source 64-slice CT (left). Photos courtesy Dr. U. Joseph Schoepf

CHICAGO — Dual-source computed tomography significantly reduces radiation exposure to patients undergoing heart scans, and eliminates the need for heart-slowing medications, according to a study presented at the annual meeting of the Radiological Society of North America.

Improved temporal resolution with dual-source CT improves diagnostic quality by significantly reducing cardiac motion artifacts, obviating the need for β-blockade, said Dr. U. Joseph Schoepf.

In addition, more effective ECG pulsing techniques and faster scan times available with dual-source CT (DSCT) significantly decrease radiation dose by an average of 10%, compared with conventional 64-slice CT, Dr. Schoepf said in an interview.

“Dual-source CT has built-in features that allow the operator to accurately tailor radiation dose to each patient,” said Dr. Schoepf, associate professor of radiology and medicine at the Medical University of South Carolina (MUSC) in Charleston.

In this study, the first 30 patients who underwent CT angiography with a DSCT scanner (SOMATOM Definition, Siemens Medical Solutions) were compared with the most recent 30 patients to undergo 64-slice CT angiography at MUSC.

“With the DSCT group, we were at the beginning of our learning curve, so by now we're even more facile in using the dual scanner than we were with the study patients,” Dr. Schoepf explained.

A fixed temporal resolution of 83 milliseconds, heart-rate adaptive pitch, and ECG pulsing were used with the DSCT in all cases. Temporal resolution at 64-slice CT was 165 milliseconds at a fixed pitch of 0.2.

With both scanners, the gantry rotation time was 330 milliseconds, collimation was 0.6 millimeters, and the injection protocol was triphasic.

A radiologist and a cardiologist who were blinded to the scanner type evaluated the coronary arteries for motion artifact using the American Heart Association segment model. Patient heart rate, radiation dose, and use of β-blockers were recorded.

“With the previous generation scanner, we still had to use β-blockers to slow heart rate to achieve good images,” Dr. Schoepf said in an interview. “We quickly learned that medications were not necessary with the DS scanner because of the faster shutter speed and better temporal resolution.”

The abandonment of ?-blockade simplifies procedural logistics, he said, explaining that the typical intravenous protocol requires having a nurse available and increases scan time because the drug is administered while the patient occupies the scanner table. “And it's always better to avoid giving drugs when you can,” he added.

The average computed tomography dose index (fundamental radiation dose parameter used in CT) volumes were 61 milligray (mGy) for patients aged 35–72 years and 53 mGy for patients aged 21–89 years, respectively (P < .001).

The average heart rates were 64 beats per minute among the control group and 73 beats per minute among those imaged with the dual scanner. β-Blockers were used in 12 of the 30 patients scanned with 64-slice CT; none were used in the DSCT group.

Cardiac motion artifacts were observed in 24% of coronary segments in 64-slice CT patients, compared with 9% of segments in the DSCT arm. In each group, data sets were completely void of motion artifacts in 3 of 30 and 12 of 30 patients, respectively.

“Overall, the diagnostic quality was better in the DSCT group despite the faster heart rates,” said Dr. Schoepf, who disclosed that he is a consultant to and has received research support from Siemens Medical Solutions and the imaging contrast divisions of Bayer, GE Healthcare, and Bracco Diagnostics. However, no outside funding was used for the current study or the scanners used in it, he said.

“With another step in the evolution of medical imaging, we're closing the gap from invasive to noninvasive diagnostic catheterization and getting to the point of being able to get the same diagnostic information, particularly for excluding coronary artery disease,” Dr. Schoepf said. “But the investment of around &dollar;2.6 million for a dual-source CT probably is only worth it if you want to exploit the particular capabilities of this device, which include the dedicated cardiac, vascular, and dual-energy applications.”

The SOMATOM Definition has been available in the United States since early 2006.

DSCT (right) of the pulmonary vein shows clearer delineation of all segments, compared with single-source 64-slice CT (left). Photos courtesy Dr. U. Joseph Schoepf

CHICAGO — A new ultrasound classification facilitates surgical decision making in the diagnosis or exclusion of appendicitis in children by elevating the importance of secondary signs, according to a study presented at the annual meeting of the Radiological Society of North America.

“This ultrasound classification improves sensitivity in children with suspected acute appendicitis. The presence of secondary signs makes acute appendicitis most likely, and the absence of these signs can safely rule out acute appendicitis in children,” said Dr. Fraukje Wiersma.

This evaluation of a new classification for diagnosing pediatric appendicitis comes at a time of increasing concern over the widespread use of computed tomography (CT) and the radiation risk it poses to children.

“Furthermore, the lack of abdominal fat in children makes them less suitable for CT,” said Dr. Wiersma, of The Hague (the Netherlands) Medical Center.

In the standing literature, the abdominal ultrasound is considered positive only when an inflamed appendix is depicted by the sonogram.

“Although secondary signs such as inflamed fat or fluid are described, they are considered to be nonspecific findings and are excluded in the calculation of sensitivity, specificity, and predictive values,” Dr. Wiersma said in an interview.

Between May 2005 and June 2006, Dr. Wiersma and her colleagues conducted ultrasound examinations of 212 consecutive pediatric patients aged 2–15 years with suspected appendicitis. Their mean age was 10 years, and 129 of the children were boys.

Depiction of the appendix was classified into four groups: in group 1, the appendix was normal; in group 2, the appendix was not depicted and no secondary signs of appendicitis were present; in group 3, the appendix was not depicted, but secondary signs of appendicitis (inflamed fat or fluid) were present; in group 4, an inflamed appendix was depicted. Patients in the first two groups had negative ultrasounds for appendicitis, whereas those in the latter two groups were considered positive and were treated surgically, she explained.

Ultrasonographic diagnoses were correlated with histopathological results or clinical follow-up.

In addition, the investigators calculated the negative appendectomy rate, the perforation rate, and predictive values of this four-part classification scheme.

Among the 96 patients in group 1, there was one false-negative, a patient who subsequently developed acute appendicitis.

Among the 41 patients in group 2 (those with no secondary signs), none had acute appendicitis at follow-up.

In group 3 (those with secondary signs, including local dilated small-bowel loop, local fluid collections, and/or increased echogenicity of mesenteric fat), 8 of the 10 patients had acute appendicitis, whereas 2 patients had negative appendectomies (1 had primary peritonitis and the other had a necrotic lymph node resected).

Of the 65 patients in group 4 in whom ultrasound had detected an inflamed appendix, 62 had acute appendicitis. Of the remainder, one patient had chronic inflammatory signs on pathological evaluation, one had a negative appendectomy (a true false-positive), and one was not operated on because of a “miscommunication” and left the hospital without further complaint.

“The prevalence of acute appendicitis in this study population was 34%, and the negative appendix read rate was comparable to that of other ultrasonographic and CT studies,” Dr. Wiersma said.

The classification developed by these Dutch researchers, under the direction of Dr. Herma C. Holscher, had a sensitivity of 99%, a specificity of 96%, a positive predictive value of 93%, a negative predictive value of 99%, and an accuracy of 97%, she reported.

Dr. Wiersma added that the sensitivity—but not specificity—is significantly higher than that of the standard method (87%) described in the literature, when applied to this study population.

“This classification of the ultrasonographic depiction of the appendix and surrounding area has high predictive values in children with suspected appendicitis, and prevents a high rate of negative appendectomies and complications of unrecognized appendicitis,” Dr. Wiersma concluded.

This ultrasound image shows a transverse section of a normal appendix with compression (white arrows).

THIS ULTRASOUND IMAGE SHOWS A LONGITUDINAL SECTION OF AN INFLAMED APPENDIX (WHITE ARROWS) WITH INCREASED ECHOGENICITY OF MESENTERIC FAT (A = APPENDICOLITH). PHOTOS COURTESY DR. FRAUKJE WIERSMA

CHICAGO — A new ultrasound classification facilitates surgical decision making in the diagnosis or exclusion of appendicitis in children by elevating the importance of secondary signs, according to a study presented at the annual meeting of the Radiological Society of North America.

“This ultrasound classification improves sensitivity in children with suspected acute appendicitis. The presence of secondary signs makes acute appendicitis most likely, and the absence of these signs can safely rule out acute appendicitis in children,” said Dr. Fraukje Wiersma.

This evaluation of a new classification for diagnosing pediatric appendicitis comes at a time of increasing concern over the widespread use of computed tomography (CT) and the radiation risk it poses to children.

“Furthermore, the lack of abdominal fat in children makes them less suitable for CT,” said Dr. Wiersma, of The Hague (the Netherlands) Medical Center.

In the standing literature, the abdominal ultrasound is considered positive only when an inflamed appendix is depicted by the sonogram.

“Although secondary signs such as inflamed fat or fluid are described, they are considered to be nonspecific findings and are excluded in the calculation of sensitivity, specificity, and predictive values,” Dr. Wiersma said in an interview.

Between May 2005 and June 2006, Dr. Wiersma and her colleagues conducted ultrasound examinations of 212 consecutive pediatric patients aged 2–15 years with suspected appendicitis. Their mean age was 10 years, and 129 of the children were boys.

Depiction of the appendix was classified into four groups: in group 1, the appendix was normal; in group 2, the appendix was not depicted and no secondary signs of appendicitis were present; in group 3, the appendix was not depicted, but secondary signs of appendicitis (inflamed fat or fluid) were present; in group 4, an inflamed appendix was depicted. Patients in the first two groups had negative ultrasounds for appendicitis, whereas those in the latter two groups were considered positive and were treated surgically, she explained.

Ultrasonographic diagnoses were correlated with histopathological results or clinical follow-up.

In addition, the investigators calculated the negative appendectomy rate, the perforation rate, and predictive values of this four-part classification scheme.

Among the 96 patients in group 1, there was one false-negative, a patient who subsequently developed acute appendicitis.

Among the 41 patients in group 2 (those with no secondary signs), none had acute appendicitis at follow-up.

In group 3 (those with secondary signs, including local dilated small-bowel loop, local fluid collections, and/or increased echogenicity of mesenteric fat), 8 of the 10 patients had acute appendicitis, whereas 2 patients had negative appendectomies (1 had primary peritonitis and the other had a necrotic lymph node resected).

Of the 65 patients in group 4 in whom ultrasound had detected an inflamed appendix, 62 had acute appendicitis. Of the remainder, one patient had chronic inflammatory signs on pathological evaluation, one had a negative appendectomy (a true false-positive), and one was not operated on because of a “miscommunication” and left the hospital without further complaint.

“The prevalence of acute appendicitis in this study population was 34%, and the negative appendix read rate was comparable to that of other ultrasonographic and CT studies,” Dr. Wiersma said.

The classification developed by these Dutch researchers, under the direction of Dr. Herma C. Holscher, had a sensitivity of 99%, a specificity of 96%, a positive predictive value of 93%, a negative predictive value of 99%, and an accuracy of 97%, she reported.

Dr. Wiersma added that the sensitivity—but not specificity—is significantly higher than that of the standard method (87%) described in the literature, when applied to this study population.

“This classification of the ultrasonographic depiction of the appendix and surrounding area has high predictive values in children with suspected appendicitis, and prevents a high rate of negative appendectomies and complications of unrecognized appendicitis,” Dr. Wiersma concluded.

This ultrasound image shows a transverse section of a normal appendix with compression (white arrows).

THIS ULTRASOUND IMAGE SHOWS A LONGITUDINAL SECTION OF AN INFLAMED APPENDIX (WHITE ARROWS) WITH INCREASED ECHOGENICITY OF MESENTERIC FAT (A = APPENDICOLITH). PHOTOS COURTESY DR. FRAUKJE WIERSMA

CHICAGO — A new ultrasound classification facilitates surgical decision making in the diagnosis or exclusion of appendicitis in children by elevating the importance of secondary signs, according to a study presented at the annual meeting of the Radiological Society of North America.

“This ultrasound classification improves sensitivity in children with suspected acute appendicitis. The presence of secondary signs makes acute appendicitis most likely, and the absence of these signs can safely rule out acute appendicitis in children,” said Dr. Fraukje Wiersma.

This evaluation of a new classification for diagnosing pediatric appendicitis comes at a time of increasing concern over the widespread use of computed tomography (CT) and the radiation risk it poses to children.

“Furthermore, the lack of abdominal fat in children makes them less suitable for CT,” said Dr. Wiersma, of The Hague (the Netherlands) Medical Center.

In the standing literature, the abdominal ultrasound is considered positive only when an inflamed appendix is depicted by the sonogram.

“Although secondary signs such as inflamed fat or fluid are described, they are considered to be nonspecific findings and are excluded in the calculation of sensitivity, specificity, and predictive values,” Dr. Wiersma said in an interview.

Between May 2005 and June 2006, Dr. Wiersma and her colleagues conducted ultrasound examinations of 212 consecutive pediatric patients aged 2–15 years with suspected appendicitis. Their mean age was 10 years, and 129 of the children were boys.

Depiction of the appendix was classified into four groups: in group 1, the appendix was normal; in group 2, the appendix was not depicted and no secondary signs of appendicitis were present; in group 3, the appendix was not depicted, but secondary signs of appendicitis (inflamed fat or fluid) were present; in group 4, an inflamed appendix was depicted. Patients in the first two groups had negative ultrasounds for appendicitis, whereas those in the latter two groups were considered positive and were treated surgically, she explained.

Ultrasonographic diagnoses were correlated with histopathological results or clinical follow-up.

In addition, the investigators calculated the negative appendectomy rate, the perforation rate, and predictive values of this four-part classification scheme.

Among the 96 patients in group 1, there was one false-negative, a patient who subsequently developed acute appendicitis.

Among the 41 patients in group 2 (those with no secondary signs), none had acute appendicitis at follow-up.

In group 3 (those with secondary signs, including local dilated small-bowel loop, local fluid collections, and/or increased echogenicity of mesenteric fat), 8 of the 10 patients had acute appendicitis, whereas 2 patients had negative appendectomies (1 had primary peritonitis and the other had a necrotic lymph node resected).

Of the 65 patients in group 4 in whom ultrasound had detected an inflamed appendix, 62 had acute appendicitis. Of the remainder, one patient had chronic inflammatory signs on pathological evaluation, one had a negative appendectomy (a true false-positive), and one was not operated on because of a “miscommunication” and left the hospital without further complaint.

“The prevalence of acute appendicitis in this study population was 34%, and the negative appendix read rate was comparable to that of other ultrasonographic and CT studies,” Dr. Wiersma said.

The classification developed by these Dutch researchers, under the direction of Dr. Herma C. Holscher, had a sensitivity of 99%, a specificity of 96%, a positive predictive value of 93%, a negative predictive value of 99%, and an accuracy of 97%, she reported.

Dr. Wiersma added that the sensitivity—but not specificity—is significantly higher than that of the standard method (87%) described in the literature, when applied to this study population.

“This classification of the ultrasonographic depiction of the appendix and surrounding area has high predictive values in children with suspected appendicitis, and prevents a high rate of negative appendectomies and complications of unrecognized appendicitis,” Dr. Wiersma concluded.

This ultrasound image shows a transverse section of a normal appendix with compression (white arrows).

THIS ULTRASOUND IMAGE SHOWS A LONGITUDINAL SECTION OF AN INFLAMED APPENDIX (WHITE ARROWS) WITH INCREASED ECHOGENICITY OF MESENTERIC FAT (A = APPENDICOLITH). PHOTOS COURTESY DR. FRAUKJE WIERSMA

CHICAGO — Restless legs syndrome affects between 5% and 15% of the population and is often manageable, yet it continues to be misdiagnosed and underreported.

Dr. Penny Tenzer told the American Academy of Family Physicians annual scientific conference that a simple mnemonic, URGE (from the words uncomfortable and urge, rest, getting up, and evening), helps identify key RLS symptoms:

▸ An uncomfortable feeling in the legs, accompanied by an urge to move.

▸ Rest or inactivity make it worse.

▸ Getting up and moving makes it better.

▸ Symptoms typically persist in the evening, often making sleeping difficult.

“I ask patients with suspected RLS is, 'do your legs keep you up at night?' That may be the first clue,” she said. If the patient answers “yes” to the rest of the questions, and there's no other apparent reason for the symptoms, then he or she has RLS.

Primary RLS likely is influenced by genetics, especially where onset occurs before the age of 45 years, she noted.

Iron deficiency, pregnancy, end-stage renal disease, peripheral neuropathy, medications, and excessive caffeine consumption may worsen symptoms, said Dr. Tenzer, director of the residency program in the department of family medicine and community health at the University of Miami.

In addition, 85% of RLS patients also have a condition called periodic limb movements of sleep (PLMS), which is marked by spontaneous jerking of a limb. “A finding of PLMS supports a diagnosis of RLS,” she said. Other comorbidities include depression, anxiety, neuropathy, narcolepsy, and apnea.

“The last supporting criterion is to give the patient a test dose of dopamine, which eases RLS symptoms,” she advised.

RLS pathophysiology relates to dopa- minergic dysfunction and iron use and storage, and decreases in iron concentration in the substantia nigra and the putamen correlate with RLS severity. “After the URGE questions, check the patient for ferritin saturation. A ferritin [reading] under 40 mcg/L may be indicative and below 20 mcg/L definitely indicative that treatment is needed.”

Before beginning pharmacotherapy, one should advise lifestyle changes such as reducing or eliminating caffeine and alcohol intake and exercising. Even mental tasks, such as doing a crossword puzzle, help.

Dopaminergic agonists, which include pramipexole and ropinerole, are the sole FDA-approved class of drugs for the treatment of primary RLS. Another option is the dopamine precursor, levadopa. Sedative-hypnotic agents often are prescribed, and patients with painful RLS may be given an anticonvulsant or opioid, she noted.

“[Dopaminergic] agonist therapy can be started in those whose symptoms occur more than twice a week. Dosages are lower than those used in Parkinson's disease. If symptoms occur less often and sleep is a problem, consider using an opioid or gabapentin as a third line, though usually two successive dopamine agonists are used.”

Dopaminergic agents require titration, and decisions to use these agents for RLS should not be based solely on the treating physician's experience with Parkinson's, which is a different disease, she cautioned.

In patients whose RLS occurs nightly, Dr. Tenzer advised avoiding levadopa-carbidopa therapy because long-term use of these drugs can produce a worsening of symptoms and symptom rebound.

Dr. Tenzer is on the speakers' bureau for Boehringer Ingelheim, which manufactures and markets Mirapex (pramipexole).

CHICAGO — Restless legs syndrome affects between 5% and 15% of the population and is often manageable, yet it continues to be misdiagnosed and underreported.

Dr. Penny Tenzer told the American Academy of Family Physicians annual scientific conference that a simple mnemonic, URGE (from the words uncomfortable and urge, rest, getting up, and evening), helps identify key RLS symptoms:

▸ An uncomfortable feeling in the legs, accompanied by an urge to move.

▸ Rest or inactivity make it worse.

▸ Getting up and moving makes it better.

▸ Symptoms typically persist in the evening, often making sleeping difficult.

“I ask patients with suspected RLS is, 'do your legs keep you up at night?' That may be the first clue,” she said. If the patient answers “yes” to the rest of the questions, and there's no other apparent reason for the symptoms, then he or she has RLS.

Primary RLS likely is influenced by genetics, especially where onset occurs before the age of 45 years, she noted.

Iron deficiency, pregnancy, end-stage renal disease, peripheral neuropathy, medications, and excessive caffeine consumption may worsen symptoms, said Dr. Tenzer, director of the residency program in the department of family medicine and community health at the University of Miami.

In addition, 85% of RLS patients also have a condition called periodic limb movements of sleep (PLMS), which is marked by spontaneous jerking of a limb. “A finding of PLMS supports a diagnosis of RLS,” she said. Other comorbidities include depression, anxiety, neuropathy, narcolepsy, and apnea.

“The last supporting criterion is to give the patient a test dose of dopamine, which eases RLS symptoms,” she advised.

RLS pathophysiology relates to dopa- minergic dysfunction and iron use and storage, and decreases in iron concentration in the substantia nigra and the putamen correlate with RLS severity. “After the URGE questions, check the patient for ferritin saturation. A ferritin [reading] under 40 mcg/L may be indicative and below 20 mcg/L definitely indicative that treatment is needed.”

Before beginning pharmacotherapy, one should advise lifestyle changes such as reducing or eliminating caffeine and alcohol intake and exercising. Even mental tasks, such as doing a crossword puzzle, help.

Dopaminergic agonists, which include pramipexole and ropinerole, are the sole FDA-approved class of drugs for the treatment of primary RLS. Another option is the dopamine precursor, levadopa. Sedative-hypnotic agents often are prescribed, and patients with painful RLS may be given an anticonvulsant or opioid, she noted.

“[Dopaminergic] agonist therapy can be started in those whose symptoms occur more than twice a week. Dosages are lower than those used in Parkinson's disease. If symptoms occur less often and sleep is a problem, consider using an opioid or gabapentin as a third line, though usually two successive dopamine agonists are used.”

Dopaminergic agents require titration, and decisions to use these agents for RLS should not be based solely on the treating physician's experience with Parkinson's, which is a different disease, she cautioned.

In patients whose RLS occurs nightly, Dr. Tenzer advised avoiding levadopa-carbidopa therapy because long-term use of these drugs can produce a worsening of symptoms and symptom rebound.

Dr. Tenzer is on the speakers' bureau for Boehringer Ingelheim, which manufactures and markets Mirapex (pramipexole).

CHICAGO — Restless legs syndrome affects between 5% and 15% of the population and is often manageable, yet it continues to be misdiagnosed and underreported.

Dr. Penny Tenzer told the American Academy of Family Physicians annual scientific conference that a simple mnemonic, URGE (from the words uncomfortable and urge, rest, getting up, and evening), helps identify key RLS symptoms:

▸ An uncomfortable feeling in the legs, accompanied by an urge to move.

▸ Rest or inactivity make it worse.

▸ Getting up and moving makes it better.

▸ Symptoms typically persist in the evening, often making sleeping difficult.

“I ask patients with suspected RLS is, 'do your legs keep you up at night?' That may be the first clue,” she said. If the patient answers “yes” to the rest of the questions, and there's no other apparent reason for the symptoms, then he or she has RLS.

Primary RLS likely is influenced by genetics, especially where onset occurs before the age of 45 years, she noted.

Iron deficiency, pregnancy, end-stage renal disease, peripheral neuropathy, medications, and excessive caffeine consumption may worsen symptoms, said Dr. Tenzer, director of the residency program in the department of family medicine and community health at the University of Miami.

In addition, 85% of RLS patients also have a condition called periodic limb movements of sleep (PLMS), which is marked by spontaneous jerking of a limb. “A finding of PLMS supports a diagnosis of RLS,” she said. Other comorbidities include depression, anxiety, neuropathy, narcolepsy, and apnea.

“The last supporting criterion is to give the patient a test dose of dopamine, which eases RLS symptoms,” she advised.

RLS pathophysiology relates to dopa- minergic dysfunction and iron use and storage, and decreases in iron concentration in the substantia nigra and the putamen correlate with RLS severity. “After the URGE questions, check the patient for ferritin saturation. A ferritin [reading] under 40 mcg/L may be indicative and below 20 mcg/L definitely indicative that treatment is needed.”

Before beginning pharmacotherapy, one should advise lifestyle changes such as reducing or eliminating caffeine and alcohol intake and exercising. Even mental tasks, such as doing a crossword puzzle, help.

Dopaminergic agonists, which include pramipexole and ropinerole, are the sole FDA-approved class of drugs for the treatment of primary RLS. Another option is the dopamine precursor, levadopa. Sedative-hypnotic agents often are prescribed, and patients with painful RLS may be given an anticonvulsant or opioid, she noted.

“[Dopaminergic] agonist therapy can be started in those whose symptoms occur more than twice a week. Dosages are lower than those used in Parkinson's disease. If symptoms occur less often and sleep is a problem, consider using an opioid or gabapentin as a third line, though usually two successive dopamine agonists are used.”

Dopaminergic agents require titration, and decisions to use these agents for RLS should not be based solely on the treating physician's experience with Parkinson's, which is a different disease, she cautioned.

In patients whose RLS occurs nightly, Dr. Tenzer advised avoiding levadopa-carbidopa therapy because long-term use of these drugs can produce a worsening of symptoms and symptom rebound.

Dr. Tenzer is on the speakers' bureau for Boehringer Ingelheim, which manufactures and markets Mirapex (pramipexole).

CHICAGO — A new ultrasound classification that elevates the importance of secondary signs in acute appendicitis facilitates surgical decision making in the diagnosis or exclusion of appendicitis in children.

“[It] improves sensitivity in children with suspected acute appendicitis. The presence of secondary signs makes acute appendicitis most likely, and the absence of these signs can safely rule out acute appendicitis in children,” said Dr. Fraukje Wiersma, at the annual meeting of the Radiological Society of North America

The classification for diagnosing pediatric appendicitis comes at a time of increasing concern over the widespread use of computed tomography (CT) and the radiation risk it poses to children.

“In addition, the lack of abdominal fat in children makes them less suitable for CT,” said Dr. Wiersma, of The Hague (the Netherlands) Medical Center.

According to the literature, the abdominal ultrasound is considered positive only when an inflamed appendix is depicted by the sonogram. “Although secondary signs such as inflamed fat or fluid are described, they are considered to be nonspecific findings and are excluded in the calculation of sensitivity, specificity, and predictive values,” Dr. Wiersma said in an interview.

Between May 2005 and June 2006, Dr. Wiersma and her colleagues conducted ultrasound examinations of 212 consecutive pediatric patients aged 2–15 years with suspected appendicitis. The mean age was 10 years, and 129 of the children were boys.

Depiction of the appendix was classified into four groups: In group 1, the appendix was normal; in group 2, the appendix not depicted and no secondary signs of appendicitis were present; in group 3, the appendix was not depicted, but secondary signs of appendicitis (inflamed fat or fluid) were present; and in group 4, an inflamed appendix was depicted. Patients in the first two groups had negative ultrasounds for appendicitis, whereas those in the latter two groups were considered positive and were treated surgically, she explained.

Ultrasonographic diagnoses were correlated with histopathological results or clinical follow-up. The investigators also calculated the negative appendectomy rate, the perforation rate, and predictive values of this four-part classification scheme.

In the 96 patients in group 1, there was one false negative, a patient who subsequently developed acute appendicitis. In the 41 patients in group 2 (those with no secondary signs), none had acute appendicitis at follow-up. In group 3 (those with secondary signs, including local dilated small-bowel loop, local fluid collections, and/or increased echogenicity of mesenteric fat), 8 of the 10 patients had acute appendicitis, whereas 2 patients had negative appendectomies (1 had primary peritonitis and the other had a necrotic lymph node resected). Of the 65 patients in group 4 in whom ultrasound had detected an inflamed appendix, 62 had acute appendicitis.

Of the remainder, one patient had chronic inflammatory signs on pathological evaluation, one had a negative appendectomy (a true false-positive), and one was not operated on because of a “miscommunication” and left the hospital without further complaint.

“The prevalence of acute appendicitis in this study population was 34%, and the negative appendix read rate was comparable with that of other ultrasonographic and CT studies,” Dr. Wiersma said.

The classification developed by the researchers, under the direction of Dr. Herma C. Holscher, had a sensitivity of 99%, a specificity of 96%, a positive predictive value of 93%, a negative predictive value of 99%, and an accuracy of 97%, she said, adding that the sensitivity—but not specificity—is significantly higher than that of the standard method (87%) described in the literature, when applied to this study population, she said.

The ultrasound image (left) shows a transverse section of a normal appendix. The longitudinal section (right) shows an inflamed appendix (arrows) and mesenteric fat. Photos courtesy Dr. Fraukje Wiersma

CHICAGO — A new ultrasound classification that elevates the importance of secondary signs in acute appendicitis facilitates surgical decision making in the diagnosis or exclusion of appendicitis in children.

“[It] improves sensitivity in children with suspected acute appendicitis. The presence of secondary signs makes acute appendicitis most likely, and the absence of these signs can safely rule out acute appendicitis in children,” said Dr. Fraukje Wiersma, at the annual meeting of the Radiological Society of North America

The classification for diagnosing pediatric appendicitis comes at a time of increasing concern over the widespread use of computed tomography (CT) and the radiation risk it poses to children.

“In addition, the lack of abdominal fat in children makes them less suitable for CT,” said Dr. Wiersma, of The Hague (the Netherlands) Medical Center.

According to the literature, the abdominal ultrasound is considered positive only when an inflamed appendix is depicted by the sonogram. “Although secondary signs such as inflamed fat or fluid are described, they are considered to be nonspecific findings and are excluded in the calculation of sensitivity, specificity, and predictive values,” Dr. Wiersma said in an interview.

Between May 2005 and June 2006, Dr. Wiersma and her colleagues conducted ultrasound examinations of 212 consecutive pediatric patients aged 2–15 years with suspected appendicitis. The mean age was 10 years, and 129 of the children were boys.

Depiction of the appendix was classified into four groups: In group 1, the appendix was normal; in group 2, the appendix not depicted and no secondary signs of appendicitis were present; in group 3, the appendix was not depicted, but secondary signs of appendicitis (inflamed fat or fluid) were present; and in group 4, an inflamed appendix was depicted. Patients in the first two groups had negative ultrasounds for appendicitis, whereas those in the latter two groups were considered positive and were treated surgically, she explained.

Ultrasonographic diagnoses were correlated with histopathological results or clinical follow-up. The investigators also calculated the negative appendectomy rate, the perforation rate, and predictive values of this four-part classification scheme.

In the 96 patients in group 1, there was one false negative, a patient who subsequently developed acute appendicitis. In the 41 patients in group 2 (those with no secondary signs), none had acute appendicitis at follow-up. In group 3 (those with secondary signs, including local dilated small-bowel loop, local fluid collections, and/or increased echogenicity of mesenteric fat), 8 of the 10 patients had acute appendicitis, whereas 2 patients had negative appendectomies (1 had primary peritonitis and the other had a necrotic lymph node resected). Of the 65 patients in group 4 in whom ultrasound had detected an inflamed appendix, 62 had acute appendicitis.

Of the remainder, one patient had chronic inflammatory signs on pathological evaluation, one had a negative appendectomy (a true false-positive), and one was not operated on because of a “miscommunication” and left the hospital without further complaint.

“The prevalence of acute appendicitis in this study population was 34%, and the negative appendix read rate was comparable with that of other ultrasonographic and CT studies,” Dr. Wiersma said.

The classification developed by the researchers, under the direction of Dr. Herma C. Holscher, had a sensitivity of 99%, a specificity of 96%, a positive predictive value of 93%, a negative predictive value of 99%, and an accuracy of 97%, she said, adding that the sensitivity—but not specificity—is significantly higher than that of the standard method (87%) described in the literature, when applied to this study population, she said.

The ultrasound image (left) shows a transverse section of a normal appendix. The longitudinal section (right) shows an inflamed appendix (arrows) and mesenteric fat. Photos courtesy Dr. Fraukje Wiersma

CHICAGO — A new ultrasound classification that elevates the importance of secondary signs in acute appendicitis facilitates surgical decision making in the diagnosis or exclusion of appendicitis in children.

“[It] improves sensitivity in children with suspected acute appendicitis. The presence of secondary signs makes acute appendicitis most likely, and the absence of these signs can safely rule out acute appendicitis in children,” said Dr. Fraukje Wiersma, at the annual meeting of the Radiological Society of North America

The classification for diagnosing pediatric appendicitis comes at a time of increasing concern over the widespread use of computed tomography (CT) and the radiation risk it poses to children.

“In addition, the lack of abdominal fat in children makes them less suitable for CT,” said Dr. Wiersma, of The Hague (the Netherlands) Medical Center.

According to the literature, the abdominal ultrasound is considered positive only when an inflamed appendix is depicted by the sonogram. “Although secondary signs such as inflamed fat or fluid are described, they are considered to be nonspecific findings and are excluded in the calculation of sensitivity, specificity, and predictive values,” Dr. Wiersma said in an interview.

Between May 2005 and June 2006, Dr. Wiersma and her colleagues conducted ultrasound examinations of 212 consecutive pediatric patients aged 2–15 years with suspected appendicitis. The mean age was 10 years, and 129 of the children were boys.

Depiction of the appendix was classified into four groups: In group 1, the appendix was normal; in group 2, the appendix not depicted and no secondary signs of appendicitis were present; in group 3, the appendix was not depicted, but secondary signs of appendicitis (inflamed fat or fluid) were present; and in group 4, an inflamed appendix was depicted. Patients in the first two groups had negative ultrasounds for appendicitis, whereas those in the latter two groups were considered positive and were treated surgically, she explained.

Ultrasonographic diagnoses were correlated with histopathological results or clinical follow-up. The investigators also calculated the negative appendectomy rate, the perforation rate, and predictive values of this four-part classification scheme.

In the 96 patients in group 1, there was one false negative, a patient who subsequently developed acute appendicitis. In the 41 patients in group 2 (those with no secondary signs), none had acute appendicitis at follow-up. In group 3 (those with secondary signs, including local dilated small-bowel loop, local fluid collections, and/or increased echogenicity of mesenteric fat), 8 of the 10 patients had acute appendicitis, whereas 2 patients had negative appendectomies (1 had primary peritonitis and the other had a necrotic lymph node resected). Of the 65 patients in group 4 in whom ultrasound had detected an inflamed appendix, 62 had acute appendicitis.

Of the remainder, one patient had chronic inflammatory signs on pathological evaluation, one had a negative appendectomy (a true false-positive), and one was not operated on because of a “miscommunication” and left the hospital without further complaint.

“The prevalence of acute appendicitis in this study population was 34%, and the negative appendix read rate was comparable with that of other ultrasonographic and CT studies,” Dr. Wiersma said.

The classification developed by the researchers, under the direction of Dr. Herma C. Holscher, had a sensitivity of 99%, a specificity of 96%, a positive predictive value of 93%, a negative predictive value of 99%, and an accuracy of 97%, she said, adding that the sensitivity—but not specificity—is significantly higher than that of the standard method (87%) described in the literature, when applied to this study population, she said.

The ultrasound image (left) shows a transverse section of a normal appendix. The longitudinal section (right) shows an inflamed appendix (arrows) and mesenteric fat. Photos courtesy Dr. Fraukje Wiersma

CHICAGO — When immunizing adolescents, body weight and injection technique should guide the choice of needle length, according to a poster study presented at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

“We looked at the performance of a 5/8-inch vs. a 1-inch needle—using both pinching and flattening of the injection site—in relation to the recipient's body weight,” said Dr. Michael Koster.

A needle that is too short might result in reduced immunogenicity and more adverse reactions to vaccines intended for intramuscular injection, whereas a needle that is too long may strike bone and injure underlying neurovascular structures, he said in an interview.

With use of the pinching technique on adolescents weighing 88–155 pounds, a 1-inch needle is appropriate. For those weighing less than 88 pounds, the shorter needle is best, said Dr. Koster, who conducted the study at Schneider Children's Hospital at North Shore in Manhasset, New York.

With use of the muscle-flattening technique, the longer needle likewise is recommended when body weight is 88–155 pounds, and the 5/8-inch needle is appropriate for adolescents weighing less than 88 pounds, said Dr. Koster, who is now a pediatric infectious disease fellow at Hasbro Children's Hospital in Providence, R.I.

The study included 141 participants. They were aged 11–15 years, with 87% of them aged 12–13 years. Of the total, 28% weighed less than 88 pounds, and about 20% weighed more than 132 pounds.

The researchers noted subjects' height, weight, and arm circumference, and conducted upper-arm ultrasonography during both muscle pinching and skin flattening of the participants' nondominant arms. The measurements were duplicated by a second researcher and averaged for analysis.

“When injecting someone [using] the pinching technique, you increase muscle and subcutaneous tissue layers, in which case you'll want a little longer needle. When flattening, typically using the forefinger and thumb, you can go up to [a weight of] about 50 kilos [110 pounds] and be safe in terms of getting the vaccine into the muscle without striking bone,” Dr. Koster said at the meeting, which was sponsored by the American Society for Microbiology.

As a general rule, with the pinching technique, a 1-inch needle is appropriate most of the time, and the shorter needle is appropriate only for patients who weigh less than 88 pounds.

With the flattening technique, the shorter length is appropriate only three-quarters of the time and only on patients weighing less than 110 pounds. “Independent of technique, it would be appropriate to use a 5/8-inch needle on subjects less than 88 pounds,” he said.

Although females had a larger subcutaneous layer than did males of the same body weight, the difference did not result in the use of a different needle length, Dr. Koster said, adding that body weight was a better predictor of required needle size than was arm circumference.

The American Academy of Pediatrics Red Book makes needle length recommendations for adolescents only in terms of body weight and sex. For example, both sizes of needles are advised for girls and boys who weigh less than 132 pounds. The 1-inch needle is recommended for girls who weigh 132–198 pounds and boys who weigh 132–260 pounds. The AAP recommends an even longer (11/2-inch) needle for females over 198 pounds and males over 260 pounds. Only 2 of the 141 subjects were that heavy, and the data on these two still are being analyzed.

Data from previous studies have suggested obese teens who are immunized with 1-inch needles develop lower hepatitis B virus (HBV) vaccine titer levels, compared with those vaccinated with 11/2-inch needles. In one study, 24 obese subjects aged 14–24 years were randomized to 1-inch and 11/2-inch needle groups, and the subjects (girls over 198 pounds and boys over 265 pounds) were given an HBV vaccination using a 0, 1-, and 4-month schedule. HBV surface antibody was obtained 2 months after the third vaccination, and data showed that the final titer levels in the 11/2-inch needle group were significantly higher than those in the 1-inch needle group (J. Adol. Health 2006;38:101).

Dr. Koster said he hoped his findings would be included in the 2009 Red Book, especially since meningococcal conjugate vaccine and human papillomavirus vaccine have been recommended for all adolescents.

If a needle is too short, it may cut immunogenicity; if it's too long, it may injure underlying structures. DR. KOSTER

CHICAGO — When immunizing adolescents, body weight and injection technique should guide the choice of needle length, according to a poster study presented at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

“We looked at the performance of a 5/8-inch vs. a 1-inch needle—using both pinching and flattening of the injection site—in relation to the recipient's body weight,” said Dr. Michael Koster.

A needle that is too short might result in reduced immunogenicity and more adverse reactions to vaccines intended for intramuscular injection, whereas a needle that is too long may strike bone and injure underlying neurovascular structures, he said in an interview.

With use of the pinching technique on adolescents weighing 88–155 pounds, a 1-inch needle is appropriate. For those weighing less than 88 pounds, the shorter needle is best, said Dr. Koster, who conducted the study at Schneider Children's Hospital at North Shore in Manhasset, New York.

With use of the muscle-flattening technique, the longer needle likewise is recommended when body weight is 88–155 pounds, and the 5/8-inch needle is appropriate for adolescents weighing less than 88 pounds, said Dr. Koster, who is now a pediatric infectious disease fellow at Hasbro Children's Hospital in Providence, R.I.

The study included 141 participants. They were aged 11–15 years, with 87% of them aged 12–13 years. Of the total, 28% weighed less than 88 pounds, and about 20% weighed more than 132 pounds.

The researchers noted subjects' height, weight, and arm circumference, and conducted upper-arm ultrasonography during both muscle pinching and skin flattening of the participants' nondominant arms. The measurements were duplicated by a second researcher and averaged for analysis.

“When injecting someone [using] the pinching technique, you increase muscle and subcutaneous tissue layers, in which case you'll want a little longer needle. When flattening, typically using the forefinger and thumb, you can go up to [a weight of] about 50 kilos [110 pounds] and be safe in terms of getting the vaccine into the muscle without striking bone,” Dr. Koster said at the meeting, which was sponsored by the American Society for Microbiology.

As a general rule, with the pinching technique, a 1-inch needle is appropriate most of the time, and the shorter needle is appropriate only for patients who weigh less than 88 pounds.

With the flattening technique, the shorter length is appropriate only three-quarters of the time and only on patients weighing less than 110 pounds. “Independent of technique, it would be appropriate to use a 5/8-inch needle on subjects less than 88 pounds,” he said.

Although females had a larger subcutaneous layer than did males of the same body weight, the difference did not result in the use of a different needle length, Dr. Koster said, adding that body weight was a better predictor of required needle size than was arm circumference.

The American Academy of Pediatrics Red Book makes needle length recommendations for adolescents only in terms of body weight and sex. For example, both sizes of needles are advised for girls and boys who weigh less than 132 pounds. The 1-inch needle is recommended for girls who weigh 132–198 pounds and boys who weigh 132–260 pounds. The AAP recommends an even longer (11/2-inch) needle for females over 198 pounds and males over 260 pounds. Only 2 of the 141 subjects were that heavy, and the data on these two still are being analyzed.

Data from previous studies have suggested obese teens who are immunized with 1-inch needles develop lower hepatitis B virus (HBV) vaccine titer levels, compared with those vaccinated with 11/2-inch needles. In one study, 24 obese subjects aged 14–24 years were randomized to 1-inch and 11/2-inch needle groups, and the subjects (girls over 198 pounds and boys over 265 pounds) were given an HBV vaccination using a 0, 1-, and 4-month schedule. HBV surface antibody was obtained 2 months after the third vaccination, and data showed that the final titer levels in the 11/2-inch needle group were significantly higher than those in the 1-inch needle group (J. Adol. Health 2006;38:101).

Dr. Koster said he hoped his findings would be included in the 2009 Red Book, especially since meningococcal conjugate vaccine and human papillomavirus vaccine have been recommended for all adolescents.

If a needle is too short, it may cut immunogenicity; if it's too long, it may injure underlying structures. DR. KOSTER

CHICAGO — When immunizing adolescents, body weight and injection technique should guide the choice of needle length, according to a poster study presented at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

“We looked at the performance of a 5/8-inch vs. a 1-inch needle—using both pinching and flattening of the injection site—in relation to the recipient's body weight,” said Dr. Michael Koster.

A needle that is too short might result in reduced immunogenicity and more adverse reactions to vaccines intended for intramuscular injection, whereas a needle that is too long may strike bone and injure underlying neurovascular structures, he said in an interview.

With use of the pinching technique on adolescents weighing 88–155 pounds, a 1-inch needle is appropriate. For those weighing less than 88 pounds, the shorter needle is best, said Dr. Koster, who conducted the study at Schneider Children's Hospital at North Shore in Manhasset, New York.

With use of the muscle-flattening technique, the longer needle likewise is recommended when body weight is 88–155 pounds, and the 5/8-inch needle is appropriate for adolescents weighing less than 88 pounds, said Dr. Koster, who is now a pediatric infectious disease fellow at Hasbro Children's Hospital in Providence, R.I.

The study included 141 participants. They were aged 11–15 years, with 87% of them aged 12–13 years. Of the total, 28% weighed less than 88 pounds, and about 20% weighed more than 132 pounds.

The researchers noted subjects' height, weight, and arm circumference, and conducted upper-arm ultrasonography during both muscle pinching and skin flattening of the participants' nondominant arms. The measurements were duplicated by a second researcher and averaged for analysis.

“When injecting someone [using] the pinching technique, you increase muscle and subcutaneous tissue layers, in which case you'll want a little longer needle. When flattening, typically using the forefinger and thumb, you can go up to [a weight of] about 50 kilos [110 pounds] and be safe in terms of getting the vaccine into the muscle without striking bone,” Dr. Koster said at the meeting, which was sponsored by the American Society for Microbiology.

As a general rule, with the pinching technique, a 1-inch needle is appropriate most of the time, and the shorter needle is appropriate only for patients who weigh less than 88 pounds.

With the flattening technique, the shorter length is appropriate only three-quarters of the time and only on patients weighing less than 110 pounds. “Independent of technique, it would be appropriate to use a 5/8-inch needle on subjects less than 88 pounds,” he said.

Although females had a larger subcutaneous layer than did males of the same body weight, the difference did not result in the use of a different needle length, Dr. Koster said, adding that body weight was a better predictor of required needle size than was arm circumference.

The American Academy of Pediatrics Red Book makes needle length recommendations for adolescents only in terms of body weight and sex. For example, both sizes of needles are advised for girls and boys who weigh less than 132 pounds. The 1-inch needle is recommended for girls who weigh 132–198 pounds and boys who weigh 132–260 pounds. The AAP recommends an even longer (11/2-inch) needle for females over 198 pounds and males over 260 pounds. Only 2 of the 141 subjects were that heavy, and the data on these two still are being analyzed.

Data from previous studies have suggested obese teens who are immunized with 1-inch needles develop lower hepatitis B virus (HBV) vaccine titer levels, compared with those vaccinated with 11/2-inch needles. In one study, 24 obese subjects aged 14–24 years were randomized to 1-inch and 11/2-inch needle groups, and the subjects (girls over 198 pounds and boys over 265 pounds) were given an HBV vaccination using a 0, 1-, and 4-month schedule. HBV surface antibody was obtained 2 months after the third vaccination, and data showed that the final titer levels in the 11/2-inch needle group were significantly higher than those in the 1-inch needle group (J. Adol. Health 2006;38:101).

Dr. Koster said he hoped his findings would be included in the 2009 Red Book, especially since meningococcal conjugate vaccine and human papillomavirus vaccine have been recommended for all adolescents.

If a needle is too short, it may cut immunogenicity; if it's too long, it may injure underlying structures. DR. KOSTER

CHICAGO – A 5-year pilot program that provides collaborative support services for people who have developmental disabilities and dementia is helping to improve their quality of life, according to a presentation at a conference on dementia sponsored by the Alzheimer's Association.

The program, launched in 2006 by the Rochester (N.Y.) chapter of the Alzheimer's Association, has served 122 developmentally disabled people with Alzheimer's disease and other dementias, about half of whom have Down syndrome. Other causes of developmental disability include cerebral palsy and mental retardation unrelated to Down syndrome.

Paula Casselman, who serves as resource director of the chapter, said more than 30% of the participants in the program have shown improvements in their activities of daily living.

Anecdotally, about half those with behavioral disturbances showed improvement as reported by caregivers. In many cases, interactions with peers also improved, Ms. Casselman said.

The program is structured around the “aging in place” model, which keeps individuals within the community, in their familiar surroundings, and close to family and friends for as long as possible. Ms. Casselman added that the model is based on three of the core services of the Alzheimer's Association, including on-site guided education, care consultation, and support (discussion) groups.

Ms. Casselman said masters-level Alzheimer's Association faculty go right into the home or the day facility to meet with the family and staff to educate them about the disease process and particular areas of need, such as simplifying activities or rearranging the environment to make it easier for the person to function.

Education also involves hands-on training in partnership with home care agencies.

“We have seven core courses in Rochester using companions and home health [caregivers] who have had extensive training in dementia care and have undergone background checks,” she said.

Care consultations include regular 6-month reviews of the individualized service plan (ISP) with the interdisciplinary team, development and implementation of an action plan based on staff and peer recommendations, and ongoing oversight of consumers' dementia-specific needs in order to promote aging in place, Ms. Casselman said. She added that the ISP–developed by the Medicaid service provider–profiles the individual and outlines the goals of those taking care of that person and how those goals are being met.

Discussion groups are informal meetings with peers who live with or close to the program participant, Ms. Casselman explained. “It's an opportunity to talk to them and find out how they're affected by having a friend with a developmental disability and AD, because these peers need information and support.”

Life enrichment was added as a fourth element of the Rochester program. It is accomplished using environmental assessments, adaptive furnishings, memory and sensory adaptations, transportation, safety devices, and respite care, Ms. Casselman said.

Caregiver support is emphasized in the Rochester project, because existing programs and staff models were not designed for the unique needs of aging people with developmental disabilities, said Sharon Boyd, senior vice president of the chapter.

Groups interested in creating programs for the developmentally disabled should first establish a relationship with their state developmental disabilities organizations, Ms. Casselman said. Such an approach also helps to garner the support of state legislators and families of the developmentally disabled.

CHICAGO – A 5-year pilot program that provides collaborative support services for people who have developmental disabilities and dementia is helping to improve their quality of life, according to a presentation at a conference on dementia sponsored by the Alzheimer's Association.

The program, launched in 2006 by the Rochester (N.Y.) chapter of the Alzheimer's Association, has served 122 developmentally disabled people with Alzheimer's disease and other dementias, about half of whom have Down syndrome. Other causes of developmental disability include cerebral palsy and mental retardation unrelated to Down syndrome.

Paula Casselman, who serves as resource director of the chapter, said more than 30% of the participants in the program have shown improvements in their activities of daily living.

Anecdotally, about half those with behavioral disturbances showed improvement as reported by caregivers. In many cases, interactions with peers also improved, Ms. Casselman said.

The program is structured around the “aging in place” model, which keeps individuals within the community, in their familiar surroundings, and close to family and friends for as long as possible. Ms. Casselman added that the model is based on three of the core services of the Alzheimer's Association, including on-site guided education, care consultation, and support (discussion) groups.

Ms. Casselman said masters-level Alzheimer's Association faculty go right into the home or the day facility to meet with the family and staff to educate them about the disease process and particular areas of need, such as simplifying activities or rearranging the environment to make it easier for the person to function.

Education also involves hands-on training in partnership with home care agencies.

“We have seven core courses in Rochester using companions and home health [caregivers] who have had extensive training in dementia care and have undergone background checks,” she said.

Care consultations include regular 6-month reviews of the individualized service plan (ISP) with the interdisciplinary team, development and implementation of an action plan based on staff and peer recommendations, and ongoing oversight of consumers' dementia-specific needs in order to promote aging in place, Ms. Casselman said. She added that the ISP–developed by the Medicaid service provider–profiles the individual and outlines the goals of those taking care of that person and how those goals are being met.

Discussion groups are informal meetings with peers who live with or close to the program participant, Ms. Casselman explained. “It's an opportunity to talk to them and find out how they're affected by having a friend with a developmental disability and AD, because these peers need information and support.”

Life enrichment was added as a fourth element of the Rochester program. It is accomplished using environmental assessments, adaptive furnishings, memory and sensory adaptations, transportation, safety devices, and respite care, Ms. Casselman said.

Caregiver support is emphasized in the Rochester project, because existing programs and staff models were not designed for the unique needs of aging people with developmental disabilities, said Sharon Boyd, senior vice president of the chapter.

Groups interested in creating programs for the developmentally disabled should first establish a relationship with their state developmental disabilities organizations, Ms. Casselman said. Such an approach also helps to garner the support of state legislators and families of the developmentally disabled.

CHICAGO – A 5-year pilot program that provides collaborative support services for people who have developmental disabilities and dementia is helping to improve their quality of life, according to a presentation at a conference on dementia sponsored by the Alzheimer's Association.

The program, launched in 2006 by the Rochester (N.Y.) chapter of the Alzheimer's Association, has served 122 developmentally disabled people with Alzheimer's disease and other dementias, about half of whom have Down syndrome. Other causes of developmental disability include cerebral palsy and mental retardation unrelated to Down syndrome.

Paula Casselman, who serves as resource director of the chapter, said more than 30% of the participants in the program have shown improvements in their activities of daily living.

Anecdotally, about half those with behavioral disturbances showed improvement as reported by caregivers. In many cases, interactions with peers also improved, Ms. Casselman said.

The program is structured around the “aging in place” model, which keeps individuals within the community, in their familiar surroundings, and close to family and friends for as long as possible. Ms. Casselman added that the model is based on three of the core services of the Alzheimer's Association, including on-site guided education, care consultation, and support (discussion) groups.

Ms. Casselman said masters-level Alzheimer's Association faculty go right into the home or the day facility to meet with the family and staff to educate them about the disease process and particular areas of need, such as simplifying activities or rearranging the environment to make it easier for the person to function.

Education also involves hands-on training in partnership with home care agencies.

“We have seven core courses in Rochester using companions and home health [caregivers] who have had extensive training in dementia care and have undergone background checks,” she said.

Care consultations include regular 6-month reviews of the individualized service plan (ISP) with the interdisciplinary team, development and implementation of an action plan based on staff and peer recommendations, and ongoing oversight of consumers' dementia-specific needs in order to promote aging in place, Ms. Casselman said. She added that the ISP–developed by the Medicaid service provider–profiles the individual and outlines the goals of those taking care of that person and how those goals are being met.

Discussion groups are informal meetings with peers who live with or close to the program participant, Ms. Casselman explained. “It's an opportunity to talk to them and find out how they're affected by having a friend with a developmental disability and AD, because these peers need information and support.”

Life enrichment was added as a fourth element of the Rochester program. It is accomplished using environmental assessments, adaptive furnishings, memory and sensory adaptations, transportation, safety devices, and respite care, Ms. Casselman said.

Caregiver support is emphasized in the Rochester project, because existing programs and staff models were not designed for the unique needs of aging people with developmental disabilities, said Sharon Boyd, senior vice president of the chapter.

Groups interested in creating programs for the developmentally disabled should first establish a relationship with their state developmental disabilities organizations, Ms. Casselman said. Such an approach also helps to garner the support of state legislators and families of the developmentally disabled.

CHICAGO — Transitional care facilities may need to consider placing incoming surgical patients in private rooms to prevent the transmission of methicillin-resistant Staphylococcus aureus, according to a poster study presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy.

The study, conducted at the MeritCare Medical Center in Fargo, N.D., revealed that methicillin-resistant S. aureus (MRSA) nasal colonization was 1.6%, which is double the national estimate reported for 2001–2002 (J. Infect. Dis. 2006;193:172–9).

The MeritCare Medical Center is a private hospital that serves as a “step-down” facility for patients awaiting nursing home placement, said Stephanie M. Borchardt, Ph.D., of the Fargo Veterans Affairs Medical Center.

Swab specimens were collected from the anterior nares of 550 transitional care unit (TCU) patients between September 2003 and November 2004. “These were older patients, most of whom were coming off a surgical service, and [they] were significantly more likely than others to be colonized with MRSA,” she said.

The median patient age was 78 years, and 64% were female. Of those positive for MRSA, more than half were being cared for by orthopedic surgery service at the time, one-third were on the cardiology or cardiothoracic surgery service, and 11% were on the general surgery service, the authors reported at a meeting sponsored by the American Society for Microbiology.

“These findings highlight the need to consider lodging surgical patients in private TCU patient rooms to prevent transmission of MRSA,” Dr. Borchardt said.

A second surveillance culture study found high rates of both MRSA and Acinetobacter baumannii colonization in patients at a long-term acute-care facility in Baltimore. Nose, perirectal, sputum, and wound cultures were collected from 35 patients; cultures were retrieved from one or more of those sites in an additional 114 patients, said Jon P. Furuno, Ph.D.

The prevalence of MRSA was 30% and of A. baumannii, 28%, said Dr. Furuno of the University of Maryland, College Park.

Anterior nares and sputum cultures were the most sensitive in identifying MRSA and A. baumannii respectively, and most A. baumannii were susceptible to ampicillin/sulbactam (93%), imipenem (90%), amikacin (80%), or trimethoprim/sulfamethoxazole (30%).

It was not surprising that over a quarter of the cultures were positive, because most of the patients in the Baltimore facility are in poor condition and have been at high risk of pathogen exposure, Dr. Furuno said in an interview.

“If a large portion of your patients are transferred from facilities where they might pick up these organisms, it's important that you have a team-based infection control system in place and that you assess the overall burden of colonization in these patients,” he concluded.

CHICAGO — Transitional care facilities may need to consider placing incoming surgical patients in private rooms to prevent the transmission of methicillin-resistant Staphylococcus aureus, according to a poster study presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy.

The study, conducted at the MeritCare Medical Center in Fargo, N.D., revealed that methicillin-resistant S. aureus (MRSA) nasal colonization was 1.6%, which is double the national estimate reported for 2001–2002 (J. Infect. Dis. 2006;193:172–9).

The MeritCare Medical Center is a private hospital that serves as a “step-down” facility for patients awaiting nursing home placement, said Stephanie M. Borchardt, Ph.D., of the Fargo Veterans Affairs Medical Center.

Swab specimens were collected from the anterior nares of 550 transitional care unit (TCU) patients between September 2003 and November 2004. “These were older patients, most of whom were coming off a surgical service, and [they] were significantly more likely than others to be colonized with MRSA,” she said.

The median patient age was 78 years, and 64% were female. Of those positive for MRSA, more than half were being cared for by orthopedic surgery service at the time, one-third were on the cardiology or cardiothoracic surgery service, and 11% were on the general surgery service, the authors reported at a meeting sponsored by the American Society for Microbiology.

“These findings highlight the need to consider lodging surgical patients in private TCU patient rooms to prevent transmission of MRSA,” Dr. Borchardt said.

A second surveillance culture study found high rates of both MRSA and Acinetobacter baumannii colonization in patients at a long-term acute-care facility in Baltimore. Nose, perirectal, sputum, and wound cultures were collected from 35 patients; cultures were retrieved from one or more of those sites in an additional 114 patients, said Jon P. Furuno, Ph.D.

The prevalence of MRSA was 30% and of A. baumannii, 28%, said Dr. Furuno of the University of Maryland, College Park.

Anterior nares and sputum cultures were the most sensitive in identifying MRSA and A. baumannii respectively, and most A. baumannii were susceptible to ampicillin/sulbactam (93%), imipenem (90%), amikacin (80%), or trimethoprim/sulfamethoxazole (30%).

It was not surprising that over a quarter of the cultures were positive, because most of the patients in the Baltimore facility are in poor condition and have been at high risk of pathogen exposure, Dr. Furuno said in an interview.

“If a large portion of your patients are transferred from facilities where they might pick up these organisms, it's important that you have a team-based infection control system in place and that you assess the overall burden of colonization in these patients,” he concluded.

CHICAGO — Transitional care facilities may need to consider placing incoming surgical patients in private rooms to prevent the transmission of methicillin-resistant Staphylococcus aureus, according to a poster study presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy.

The study, conducted at the MeritCare Medical Center in Fargo, N.D., revealed that methicillin-resistant S. aureus (MRSA) nasal colonization was 1.6%, which is double the national estimate reported for 2001–2002 (J. Infect. Dis. 2006;193:172–9).

The MeritCare Medical Center is a private hospital that serves as a “step-down” facility for patients awaiting nursing home placement, said Stephanie M. Borchardt, Ph.D., of the Fargo Veterans Affairs Medical Center.

Swab specimens were collected from the anterior nares of 550 transitional care unit (TCU) patients between September 2003 and November 2004. “These were older patients, most of whom were coming off a surgical service, and [they] were significantly more likely than others to be colonized with MRSA,” she said.

The median patient age was 78 years, and 64% were female. Of those positive for MRSA, more than half were being cared for by orthopedic surgery service at the time, one-third were on the cardiology or cardiothoracic surgery service, and 11% were on the general surgery service, the authors reported at a meeting sponsored by the American Society for Microbiology.

“These findings highlight the need to consider lodging surgical patients in private TCU patient rooms to prevent transmission of MRSA,” Dr. Borchardt said.

A second surveillance culture study found high rates of both MRSA and Acinetobacter baumannii colonization in patients at a long-term acute-care facility in Baltimore. Nose, perirectal, sputum, and wound cultures were collected from 35 patients; cultures were retrieved from one or more of those sites in an additional 114 patients, said Jon P. Furuno, Ph.D.

The prevalence of MRSA was 30% and of A. baumannii, 28%, said Dr. Furuno of the University of Maryland, College Park.

Anterior nares and sputum cultures were the most sensitive in identifying MRSA and A. baumannii respectively, and most A. baumannii were susceptible to ampicillin/sulbactam (93%), imipenem (90%), amikacin (80%), or trimethoprim/sulfamethoxazole (30%).

It was not surprising that over a quarter of the cultures were positive, because most of the patients in the Baltimore facility are in poor condition and have been at high risk of pathogen exposure, Dr. Furuno said in an interview.

“If a large portion of your patients are transferred from facilities where they might pick up these organisms, it's important that you have a team-based infection control system in place and that you assess the overall burden of colonization in these patients,” he concluded.

CHICAGO — Offering prophylaxis to all household contacts of patients with invasive group A streptococcal disease may not be cost effective, according to findings from an epidemiologic study presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy.

The Centers for Disease Control and Prevention recommends that chemoprophylaxis be given only to household contacts at increased risk of group A streptococcus (GAS) disease. In the United Kingdom, chemoprophylaxis is routinely given to maternal or neonatal index cases, Dr. Stephanie W. Smith explained.

In Canada, however, where the study was conducted, guidelines recommend that if a household member has more than 4 hours of contact with the index case in the 7 days prior to onset of illness, then that person should be offered chemoprophylaxis.

In a study aimed at describing the epidemiology of household clusters of invasive GAS, Dr. Smith and her colleagues analyzed data on 12 million people in Ontario.

“In looking at the issue of prophylaxis, over the period from 1992 to 2001 we had over 2,000 cases of invasive GAS, and we had another 982 cases from 2001 to 2004, of which 610 were from the population base of 4 million people in the Toronto area,” said Dr. Smith of the division of infectious diseases at the University of Alberta in Edmonton.

The incidence of invasive GAS ranged from 1.5 to 3.4 per 100,000 people; data regarding prophylaxis of household contacts were available for 968 cases, Dr. Smith said.

Results from previous population-based studies suggest that the worldwide annual incidence of invasive GAS is between 1.25 and 6 per 100,000, she explained.

The researchers identified eight household clusters, each consisting of two cases of GAS disease, including four husband-wife pairs, one brother-brother pair, two mother-son pairs, and one father-daughter pair, she said, adding that the average age of secondary cases was 54 years (range 29–83 years).

Risk factors for sporadic disease include residence in a nursing home, extremes of age, recent varicella infection, HIV, diabetes, heart disease, cancer, use of high-dose steroids, and intravenous drug use.

In this study, only two of the secondary cases had risk factors for sporadic GAS disease, Dr. Smith said at the meeting, which was sponsored by the American Society for Microbiology.

All cases had bacteremia, including one pair with necrotizing fasciitis, one pair with prepatellar bursitis, three pairs with soft tissue infection, and one pair with soft tissue infection and peritonitis.

None of the secondary cases received chemoprophylaxis, and all primary and secondary cases within these eight households survived, Dr. Smith said, adding that of the 968 cases with documentation regarding chemoprophylaxis, only 28% of household contacts received it, suggesting a low adherence to Canadian guidelines.

Prophylaxis may have prevented several secondary cases, “but we still think our data are reasonably robust and represent the largest series of household clusters,” Dr. Smith said in an interview.

“If we assume 100% efficacy of prophylaxis, based on our secondary infection rate in Ontario, we would have to treat 806 household contacts to prevent one case of invasive disease at an estimated cost of $33,000 per case prevented,” she said, adding that a formal cost-effectiveness analysis was not completed.

Invasive group A streptococcus can cause a variety of invasive syndromes, including necrotizing fasciitis, toxic shock syndrome, pneumonia, and bacteremia. The overall mortality rate of between 10% and 20% is highest among the elderly, the very young, and those who have had a recent varicella infection or who have other comorbidities.

“We think the secondary attack rate is a bit higher than the sporadic rate, but [it] is definitely lower than what we found in the initial Ontario data, and the most common risk factor does seem to be advanced age,” Dr. Smith said, adding that offering all household contacts chemoprophylaxis may not be cost-effective given the combined public health and antibiotic costs.

“However, offering prophylaxis to those at increased risk for sporadic disease or for severe disease … may be the most cost-effective approach,” she said.

CHICAGO — Offering prophylaxis to all household contacts of patients with invasive group A streptococcal disease may not be cost effective, according to findings from an epidemiologic study presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy.

The Centers for Disease Control and Prevention recommends that chemoprophylaxis be given only to household contacts at increased risk of group A streptococcus (GAS) disease. In the United Kingdom, chemoprophylaxis is routinely given to maternal or neonatal index cases, Dr. Stephanie W. Smith explained.

In Canada, however, where the study was conducted, guidelines recommend that if a household member has more than 4 hours of contact with the index case in the 7 days prior to onset of illness, then that person should be offered chemoprophylaxis.

In a study aimed at describing the epidemiology of household clusters of invasive GAS, Dr. Smith and her colleagues analyzed data on 12 million people in Ontario.

“In looking at the issue of prophylaxis, over the period from 1992 to 2001 we had over 2,000 cases of invasive GAS, and we had another 982 cases from 2001 to 2004, of which 610 were from the population base of 4 million people in the Toronto area,” said Dr. Smith of the division of infectious diseases at the University of Alberta in Edmonton.

The incidence of invasive GAS ranged from 1.5 to 3.4 per 100,000 people; data regarding prophylaxis of household contacts were available for 968 cases, Dr. Smith said.

Results from previous population-based studies suggest that the worldwide annual incidence of invasive GAS is between 1.25 and 6 per 100,000, she explained.

The researchers identified eight household clusters, each consisting of two cases of GAS disease, including four husband-wife pairs, one brother-brother pair, two mother-son pairs, and one father-daughter pair, she said, adding that the average age of secondary cases was 54 years (range 29–83 years).

Risk factors for sporadic disease include residence in a nursing home, extremes of age, recent varicella infection, HIV, diabetes, heart disease, cancer, use of high-dose steroids, and intravenous drug use.

In this study, only two of the secondary cases had risk factors for sporadic GAS disease, Dr. Smith said at the meeting, which was sponsored by the American Society for Microbiology.

All cases had bacteremia, including one pair with necrotizing fasciitis, one pair with prepatellar bursitis, three pairs with soft tissue infection, and one pair with soft tissue infection and peritonitis.

None of the secondary cases received chemoprophylaxis, and all primary and secondary cases within these eight households survived, Dr. Smith said, adding that of the 968 cases with documentation regarding chemoprophylaxis, only 28% of household contacts received it, suggesting a low adherence to Canadian guidelines.

Prophylaxis may have prevented several secondary cases, “but we still think our data are reasonably robust and represent the largest series of household clusters,” Dr. Smith said in an interview.

“If we assume 100% efficacy of prophylaxis, based on our secondary infection rate in Ontario, we would have to treat 806 household contacts to prevent one case of invasive disease at an estimated cost of $33,000 per case prevented,” she said, adding that a formal cost-effectiveness analysis was not completed.

Invasive group A streptococcus can cause a variety of invasive syndromes, including necrotizing fasciitis, toxic shock syndrome, pneumonia, and bacteremia. The overall mortality rate of between 10% and 20% is highest among the elderly, the very young, and those who have had a recent varicella infection or who have other comorbidities.

“We think the secondary attack rate is a bit higher than the sporadic rate, but [it] is definitely lower than what we found in the initial Ontario data, and the most common risk factor does seem to be advanced age,” Dr. Smith said, adding that offering all household contacts chemoprophylaxis may not be cost-effective given the combined public health and antibiotic costs.

“However, offering prophylaxis to those at increased risk for sporadic disease or for severe disease … may be the most cost-effective approach,” she said.

CHICAGO — Offering prophylaxis to all household contacts of patients with invasive group A streptococcal disease may not be cost effective, according to findings from an epidemiologic study presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy.

The Centers for Disease Control and Prevention recommends that chemoprophylaxis be given only to household contacts at increased risk of group A streptococcus (GAS) disease. In the United Kingdom, chemoprophylaxis is routinely given to maternal or neonatal index cases, Dr. Stephanie W. Smith explained.

In Canada, however, where the study was conducted, guidelines recommend that if a household member has more than 4 hours of contact with the index case in the 7 days prior to onset of illness, then that person should be offered chemoprophylaxis.

In a study aimed at describing the epidemiology of household clusters of invasive GAS, Dr. Smith and her colleagues analyzed data on 12 million people in Ontario.

“In looking at the issue of prophylaxis, over the period from 1992 to 2001 we had over 2,000 cases of invasive GAS, and we had another 982 cases from 2001 to 2004, of which 610 were from the population base of 4 million people in the Toronto area,” said Dr. Smith of the division of infectious diseases at the University of Alberta in Edmonton.

The incidence of invasive GAS ranged from 1.5 to 3.4 per 100,000 people; data regarding prophylaxis of household contacts were available for 968 cases, Dr. Smith said.

Results from previous population-based studies suggest that the worldwide annual incidence of invasive GAS is between 1.25 and 6 per 100,000, she explained.

The researchers identified eight household clusters, each consisting of two cases of GAS disease, including four husband-wife pairs, one brother-brother pair, two mother-son pairs, and one father-daughter pair, she said, adding that the average age of secondary cases was 54 years (range 29–83 years).

Risk factors for sporadic disease include residence in a nursing home, extremes of age, recent varicella infection, HIV, diabetes, heart disease, cancer, use of high-dose steroids, and intravenous drug use.

In this study, only two of the secondary cases had risk factors for sporadic GAS disease, Dr. Smith said at the meeting, which was sponsored by the American Society for Microbiology.

All cases had bacteremia, including one pair with necrotizing fasciitis, one pair with prepatellar bursitis, three pairs with soft tissue infection, and one pair with soft tissue infection and peritonitis.

None of the secondary cases received chemoprophylaxis, and all primary and secondary cases within these eight households survived, Dr. Smith said, adding that of the 968 cases with documentation regarding chemoprophylaxis, only 28% of household contacts received it, suggesting a low adherence to Canadian guidelines.

Prophylaxis may have prevented several secondary cases, “but we still think our data are reasonably robust and represent the largest series of household clusters,” Dr. Smith said in an interview.

“If we assume 100% efficacy of prophylaxis, based on our secondary infection rate in Ontario, we would have to treat 806 household contacts to prevent one case of invasive disease at an estimated cost of $33,000 per case prevented,” she said, adding that a formal cost-effectiveness analysis was not completed.

Invasive group A streptococcus can cause a variety of invasive syndromes, including necrotizing fasciitis, toxic shock syndrome, pneumonia, and bacteremia. The overall mortality rate of between 10% and 20% is highest among the elderly, the very young, and those who have had a recent varicella infection or who have other comorbidities.

“We think the secondary attack rate is a bit higher than the sporadic rate, but [it] is definitely lower than what we found in the initial Ontario data, and the most common risk factor does seem to be advanced age,” Dr. Smith said, adding that offering all household contacts chemoprophylaxis may not be cost-effective given the combined public health and antibiotic costs.

“However, offering prophylaxis to those at increased risk for sporadic disease or for severe disease … may be the most cost-effective approach,” she said.

CHICAGO — When immunizing adolescents, body weight and injection technique should guide the needle choice, according to a poster presented at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

Using a needle that is too short may result in reduced immunogenicity and more adverse reactions to vaccines intended for intramuscular injection. Using a needle that is too long may strike bone and injure underlying neurovascular structures, Dr. Michael Koster said in an interview.

With use of the pinching technique on adolescents weighing 88-155 pounds, a 1-inch needle is appropriate. For adolescents less than 88 pounds, a shorter needle is best, said Dr. Koster, who conducted the study at Schneider Children's Hospital at North Shore in Manhasset, New York.

With use of the muscle-flattening technique, the longer needle likewise is recommended when body weight is 88-155 pounds, and the 5/8-inch needle is appropriate for adolescents weighing less than 88 pounds, said Dr. Koster, who is now a pediatric infectious disease fellow at Hasbro Children's Hospital in Providence, R.I.

The investigation included 141 participants aged 11-15 years, with 87% aged 12-13. Of the total, 28% weighed less than 88 pounds, while about 20% weighed more than 132 pounds.

The investigators recorded the adolescents' height, weight, and arm circumference, and conducted upper-arm ultrasonography during both muscle pinching and skin flattening of the participants' nondominant arms. These measurements were duplicated by a second investigator and averaged.

"When injecting someone [while using] the pinching technique, you increase muscle and subcutaneous tissue layers, in which case you'll want a little longer needle. When flattening, typically using the forefinger and thumb, you can go up to [a weight of] about 50 kilos [110 pounds] and be safe in terms of getting the vaccine into the muscle without striking bone," Dr. Koster said at the meeting, which was sponsored by the American Society for Microbiology.

As a general rule, with the pinching technique, a 1-inch needle is appropriate most of the time, and the shorter needle is appropriate only for patients who weigh less than 88 pounds.

With the flattening technique, the shorter length is appropriate only three-quarters of the time and only on patients weighing less than 110 pounds. "Independent of technique, it would be appropriate to use a 5/8-inch needle on subjects less than 88 pounds," he said.

Although females had a larger subcutaneous layer than did males of the same body weight, the difference did not result in the use of a different needle, Dr. Koster said, adding body weight was a better predictor of required needle size than was arm circumference.

The American Academy of Pediatrics Red Book makes needle length recommendations for adolescents only in terms of body weight and sex. For example, both sizes of needles are recommended for girls and boys who weigh less than 132 pounds. The 1-inch needle is recommended for girls who weigh 132-198 pounds and boys who weigh 132-260 pounds. The AAP recommends a 11/2-inch needle for females over 198 pounds and males over 260 pounds. Only 2 of the 141 subjects were that heavy, and the data on these two still are being analyzed.

Previous data have suggested obese adolescents immunized with 1-inch needles develop lower hepatitis B virus (HBV) vaccine titer levels, versus those vaccinated with 11/2-inch needles. Indeed, this seemed to be the case in a limited study of 24 obese subjects aged 14-24 years (J. Adol. Health 2006;38:101).

In that study, after randomization to 1-inch and 11/2-inch needle groups, subjects (girls over 198 pounds and boys over 265 pounds) were given an HBV vaccination using a 0, 1-, and 4-month schedule. HBV surface antibody was obtained 2 months after the third vaccination, and data showed the final titer levels in the 11/2-inch needle group were statistically significantly higher than those in the 1-inch needle group.

"I hope that adjustments are made in the 2009 Red Book to reflect our finding that optimal needle length is influenced by intramuscular injection technique," Dr. Koster said, adding that meningococcal conjugate vaccine, and human papillomavirus vaccine recently have been licensed and recommended for all adolescents in the United States.

The patient's body weight is a better predictor of required needle length than is arm circumference. DR. KOSTER

CHICAGO — When immunizing adolescents, body weight and injection technique should guide the needle choice, according to a poster presented at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

Using a needle that is too short may result in reduced immunogenicity and more adverse reactions to vaccines intended for intramuscular injection. Using a needle that is too long may strike bone and injure underlying neurovascular structures, Dr. Michael Koster said in an interview.

With use of the pinching technique on adolescents weighing 88-155 pounds, a 1-inch needle is appropriate. For adolescents less than 88 pounds, a shorter needle is best, said Dr. Koster, who conducted the study at Schneider Children's Hospital at North Shore in Manhasset, New York.

With use of the muscle-flattening technique, the longer needle likewise is recommended when body weight is 88-155 pounds, and the 5/8-inch needle is appropriate for adolescents weighing less than 88 pounds, said Dr. Koster, who is now a pediatric infectious disease fellow at Hasbro Children's Hospital in Providence, R.I.

The investigation included 141 participants aged 11-15 years, with 87% aged 12-13. Of the total, 28% weighed less than 88 pounds, while about 20% weighed more than 132 pounds.

The investigators recorded the adolescents' height, weight, and arm circumference, and conducted upper-arm ultrasonography during both muscle pinching and skin flattening of the participants' nondominant arms. These measurements were duplicated by a second investigator and averaged.

"When injecting someone [while using] the pinching technique, you increase muscle and subcutaneous tissue layers, in which case you'll want a little longer needle. When flattening, typically using the forefinger and thumb, you can go up to [a weight of] about 50 kilos [110 pounds] and be safe in terms of getting the vaccine into the muscle without striking bone," Dr. Koster said at the meeting, which was sponsored by the American Society for Microbiology.

As a general rule, with the pinching technique, a 1-inch needle is appropriate most of the time, and the shorter needle is appropriate only for patients who weigh less than 88 pounds.

With the flattening technique, the shorter length is appropriate only three-quarters of the time and only on patients weighing less than 110 pounds. "Independent of technique, it would be appropriate to use a 5/8-inch needle on subjects less than 88 pounds," he said.

Although females had a larger subcutaneous layer than did males of the same body weight, the difference did not result in the use of a different needle, Dr. Koster said, adding body weight was a better predictor of required needle size than was arm circumference.

The American Academy of Pediatrics Red Book makes needle length recommendations for adolescents only in terms of body weight and sex. For example, both sizes of needles are recommended for girls and boys who weigh less than 132 pounds. The 1-inch needle is recommended for girls who weigh 132-198 pounds and boys who weigh 132-260 pounds. The AAP recommends a 11/2-inch needle for females over 198 pounds and males over 260 pounds. Only 2 of the 141 subjects were that heavy, and the data on these two still are being analyzed.

Previous data have suggested obese adolescents immunized with 1-inch needles develop lower hepatitis B virus (HBV) vaccine titer levels, versus those vaccinated with 11/2-inch needles. Indeed, this seemed to be the case in a limited study of 24 obese subjects aged 14-24 years (J. Adol. Health 2006;38:101).

In that study, after randomization to 1-inch and 11/2-inch needle groups, subjects (girls over 198 pounds and boys over 265 pounds) were given an HBV vaccination using a 0, 1-, and 4-month schedule. HBV surface antibody was obtained 2 months after the third vaccination, and data showed the final titer levels in the 11/2-inch needle group were statistically significantly higher than those in the 1-inch needle group.

"I hope that adjustments are made in the 2009 Red Book to reflect our finding that optimal needle length is influenced by intramuscular injection technique," Dr. Koster said, adding that meningococcal conjugate vaccine, and human papillomavirus vaccine recently have been licensed and recommended for all adolescents in the United States.

The patient's body weight is a better predictor of required needle length than is arm circumference. DR. KOSTER

CHICAGO — When immunizing adolescents, body weight and injection technique should guide the needle choice, according to a poster presented at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

Using a needle that is too short may result in reduced immunogenicity and more adverse reactions to vaccines intended for intramuscular injection. Using a needle that is too long may strike bone and injure underlying neurovascular structures, Dr. Michael Koster said in an interview.

With use of the pinching technique on adolescents weighing 88-155 pounds, a 1-inch needle is appropriate. For adolescents less than 88 pounds, a shorter needle is best, said Dr. Koster, who conducted the study at Schneider Children's Hospital at North Shore in Manhasset, New York.

With use of the muscle-flattening technique, the longer needle likewise is recommended when body weight is 88-155 pounds, and the 5/8-inch needle is appropriate for adolescents weighing less than 88 pounds, said Dr. Koster, who is now a pediatric infectious disease fellow at Hasbro Children's Hospital in Providence, R.I.

The investigation included 141 participants aged 11-15 years, with 87% aged 12-13. Of the total, 28% weighed less than 88 pounds, while about 20% weighed more than 132 pounds.

The investigators recorded the adolescents' height, weight, and arm circumference, and conducted upper-arm ultrasonography during both muscle pinching and skin flattening of the participants' nondominant arms. These measurements were duplicated by a second investigator and averaged.

"When injecting someone [while using] the pinching technique, you increase muscle and subcutaneous tissue layers, in which case you'll want a little longer needle. When flattening, typically using the forefinger and thumb, you can go up to [a weight of] about 50 kilos [110 pounds] and be safe in terms of getting the vaccine into the muscle without striking bone," Dr. Koster said at the meeting, which was sponsored by the American Society for Microbiology.

As a general rule, with the pinching technique, a 1-inch needle is appropriate most of the time, and the shorter needle is appropriate only for patients who weigh less than 88 pounds.

With the flattening technique, the shorter length is appropriate only three-quarters of the time and only on patients weighing less than 110 pounds. "Independent of technique, it would be appropriate to use a 5/8-inch needle on subjects less than 88 pounds," he said.

Although females had a larger subcutaneous layer than did males of the same body weight, the difference did not result in the use of a different needle, Dr. Koster said, adding body weight was a better predictor of required needle size than was arm circumference.

The American Academy of Pediatrics Red Book makes needle length recommendations for adolescents only in terms of body weight and sex. For example, both sizes of needles are recommended for girls and boys who weigh less than 132 pounds. The 1-inch needle is recommended for girls who weigh 132-198 pounds and boys who weigh 132-260 pounds. The AAP recommends a 11/2-inch needle for females over 198 pounds and males over 260 pounds. Only 2 of the 141 subjects were that heavy, and the data on these two still are being analyzed.

Previous data have suggested obese adolescents immunized with 1-inch needles develop lower hepatitis B virus (HBV) vaccine titer levels, versus those vaccinated with 11/2-inch needles. Indeed, this seemed to be the case in a limited study of 24 obese subjects aged 14-24 years (J. Adol. Health 2006;38:101).

In that study, after randomization to 1-inch and 11/2-inch needle groups, subjects (girls over 198 pounds and boys over 265 pounds) were given an HBV vaccination using a 0, 1-, and 4-month schedule. HBV surface antibody was obtained 2 months after the third vaccination, and data showed the final titer levels in the 11/2-inch needle group were statistically significantly higher than those in the 1-inch needle group.

"I hope that adjustments are made in the 2009 Red Book to reflect our finding that optimal needle length is influenced by intramuscular injection technique," Dr. Koster said, adding that meningococcal conjugate vaccine, and human papillomavirus vaccine recently have been licensed and recommended for all adolescents in the United States.

The patient's body weight is a better predictor of required needle length than is arm circumference. DR. KOSTER

CHICAGO — The first reported treatment of fresh scars with fractional resurfacing shows the modality to be both safe and effective, which places the device in direct competition with the carbon dioxide laser.

"Fractional laser treatment using the 1,550-nm erbium fiber laser produced significant improvement in all characteristics of fresh scars," said Dr. Cameron Rokhsar, at the annual meeting of the American Society for Dermatologic Surgery.

Studies of carbon dioxide and, more recently, pulsed dye laser treatment, have shown improvements in the range of 50%-60%, which are on a par with dermabrasion, said Dr. Rokhsar of the division of dermatology at the Albert Einstein College of Medicine, New York.

Dr. Rokhsar's study included 10 patients who received half-scar treatment with the nonablative Fraxel SR 750 system at or within 2 weeks of suture removal. The untreated half of each scar served as the control. The study was sponsored through a research grant by Reliant Technologies Inc., manufacturer of the Fraxel laser system. Reliant provided the devices that were used in the study. Dr. Rokhsar is a consultant for the company.

Patients were 19-74 years old; the study excluded those with localized or systemic infections and those being treated with isotretinoin, Dr. Rokhsar said.

Half of each scar was treated every other week for 10 weeks (five sessions) using an energy level of 20 mJ and a density of 1,000-2,000 microthermal zones per square centimeter.

The patients were evaluated at 1 month and 3 months after the last treatment based on a quartile scale of 0-4 (0, no improvement; 2, 26%-50% improvement; 3, 51%-75% improvement; and 4, 76%-100% improvement), he explained.

After 3 months, all treated scar portions were rated as either 2 or 3. "The improvements were moderate to significant for all scar characteristics, with both the patients and the study investigators reporting that improvement scores for skin texture, pigmentation, and overall atrophic scar appearance were well correlated," Dr. Rokhsar said.

"The treatments were safe and well tolerated," he noted. At 1 month following the last treatment, "three subjects had mild erythema and a fourth had transient postinflammatory hyperpigmentation; all resolved by 3 months."

The bottom half of this vertical scar (starting at ruler edge) was resurfaced five times with a Fraxel laser. Courtesy Dr. Cameron Rokhsar

CHICAGO — The first reported treatment of fresh scars with fractional resurfacing shows the modality to be both safe and effective, which places the device in direct competition with the carbon dioxide laser.

"Fractional laser treatment using the 1,550-nm erbium fiber laser produced significant improvement in all characteristics of fresh scars," said Dr. Cameron Rokhsar, at the annual meeting of the American Society for Dermatologic Surgery.

Studies of carbon dioxide and, more recently, pulsed dye laser treatment, have shown improvements in the range of 50%-60%, which are on a par with dermabrasion, said Dr. Rokhsar of the division of dermatology at the Albert Einstein College of Medicine, New York.

Dr. Rokhsar's study included 10 patients who received half-scar treatment with the nonablative Fraxel SR 750 system at or within 2 weeks of suture removal. The untreated half of each scar served as the control. The study was sponsored through a research grant by Reliant Technologies Inc., manufacturer of the Fraxel laser system. Reliant provided the devices that were used in the study. Dr. Rokhsar is a consultant for the company.

Patients were 19-74 years old; the study excluded those with localized or systemic infections and those being treated with isotretinoin, Dr. Rokhsar said.

Half of each scar was treated every other week for 10 weeks (five sessions) using an energy level of 20 mJ and a density of 1,000-2,000 microthermal zones per square centimeter.

The patients were evaluated at 1 month and 3 months after the last treatment based on a quartile scale of 0-4 (0, no improvement; 2, 26%-50% improvement; 3, 51%-75% improvement; and 4, 76%-100% improvement), he explained.

After 3 months, all treated scar portions were rated as either 2 or 3. "The improvements were moderate to significant for all scar characteristics, with both the patients and the study investigators reporting that improvement scores for skin texture, pigmentation, and overall atrophic scar appearance were well correlated," Dr. Rokhsar said.

"The treatments were safe and well tolerated," he noted. At 1 month following the last treatment, "three subjects had mild erythema and a fourth had transient postinflammatory hyperpigmentation; all resolved by 3 months."

The bottom half of this vertical scar (starting at ruler edge) was resurfaced five times with a Fraxel laser. Courtesy Dr. Cameron Rokhsar

CHICAGO — The first reported treatment of fresh scars with fractional resurfacing shows the modality to be both safe and effective, which places the device in direct competition with the carbon dioxide laser.

"Fractional laser treatment using the 1,550-nm erbium fiber laser produced significant improvement in all characteristics of fresh scars," said Dr. Cameron Rokhsar, at the annual meeting of the American Society for Dermatologic Surgery.

Studies of carbon dioxide and, more recently, pulsed dye laser treatment, have shown improvements in the range of 50%-60%, which are on a par with dermabrasion, said Dr. Rokhsar of the division of dermatology at the Albert Einstein College of Medicine, New York.

Dr. Rokhsar's study included 10 patients who received half-scar treatment with the nonablative Fraxel SR 750 system at or within 2 weeks of suture removal. The untreated half of each scar served as the control. The study was sponsored through a research grant by Reliant Technologies Inc., manufacturer of the Fraxel laser system. Reliant provided the devices that were used in the study. Dr. Rokhsar is a consultant for the company.

Patients were 19-74 years old; the study excluded those with localized or systemic infections and those being treated with isotretinoin, Dr. Rokhsar said.

Half of each scar was treated every other week for 10 weeks (five sessions) using an energy level of 20 mJ and a density of 1,000-2,000 microthermal zones per square centimeter.

The patients were evaluated at 1 month and 3 months after the last treatment based on a quartile scale of 0-4 (0, no improvement; 2, 26%-50% improvement; 3, 51%-75% improvement; and 4, 76%-100% improvement), he explained.

After 3 months, all treated scar portions were rated as either 2 or 3. "The improvements were moderate to significant for all scar characteristics, with both the patients and the study investigators reporting that improvement scores for skin texture, pigmentation, and overall atrophic scar appearance were well correlated," Dr. Rokhsar said.

"The treatments were safe and well tolerated," he noted. At 1 month following the last treatment, "three subjects had mild erythema and a fourth had transient postinflammatory hyperpigmentation; all resolved by 3 months."

The bottom half of this vertical scar (starting at ruler edge) was resurfaced five times with a Fraxel laser. Courtesy Dr. Cameron Rokhsar