Aram Barbaryan, MD

No. After thoracentesis, chest radiography or another lung imaging study should be done only if pneumothorax is suspected, if thoracentesis requires more than 1 attempt, if the patient is on mechanical ventilation or has pre-existing lung disease, or if a large volume (> 1,500 mL) of fluid is removed. Radiography is also usually not necessary after diagnostic thoracentesis in a patient breathing spontaneously. In most cases, pneumothorax found incidentally after thoracentesis does not require decompression and can be managed supportively.

WHAT ARE THE RISKS OF THORACENTESIS?

Thoracentesis is a minimally invasive procedure usually performed at the bedside that involves insertion of a needle into the pleural cavity for drainage of fluid.¹ Diagnostic thoracentesis should be done in most cases of a new pleural effusion unless the effusion is small and with a clear diagnosis, or in cases of typical heart failure.

Therapeutic thoracentesis, often called large-volume thoracentesis, aims to improve symptoms such as dyspnea attributed to the pleural effusion by removing at least 1 L of pleural fluid. The presence of active respiratory symptoms and suspicion of infected pleural effusion should lead to thoracentesis as soon as possible.

Complications of thoracentesis may be benign, such as pain and anxiety associated with the procedure and external bleeding at the site of needle insertion. Pneumothorax is the most common serious procedural complication and the principal reason to order postprocedural chest radiography.¹ Less common complications include hemothorax, re-expansion pulmonary edema, infection, subdiaphragmatic organ puncture, and procedure-related death. Bleeding complications and hemothorax are rare even in patients with underlying coagulopathy.²

Point-of-care pleural ultrasonography is now considered the standard of care to guide optimal needle location for the procedure and to exclude other conditions that can mimic pleural effusion on chest radiography, such as lung consolidation and atelectasis.³ High proficiency in the use of preprocedural point-of-care ultrasonography reduces the rate of procedural complications, though it does not eliminate the risk entirely.^3,4

Factors associated with higher rates of complications include lack of operator proficiency, poor understanding of the anatomy, poor patient positioning, poor patient cooperation with the procedure, lack of availability of bedside ultrasonography, and drainage of more than 1,500 mL of fluid. Addressing these factors has been shown to decrease the risk of pneumothorax and infection.^1–5

HOW OFTEN DOES PNEUMOTHORAX OCCUR AFTER THORACENTESIS?

Several early studies have examined the incidence of pneumothorax after thoracentesis. Lack of ultrasonography use likely explains a higher incidence of complications in early studies: rates of pneumothorax after thoracentesis without ultrasonographic guidance ranged from 5.2% to 26%.^6,7

Gervais et al⁸ analyzed thoracentesis with ultrasonographic guidance in 434 patients, 92 of whom were intubated, and reported that pneumothorax occurred in 10 patients, of whom 6 were intubated. Two of the intubated patients required chest tubes. Other studies have confirmed the low incidence of pneumothorax in patients undergoing thoracentesis, with rates such as 0.61%,¹ 5%,9 and 4%.¹⁰

The major predictor of postprocedural pneumothorax was the presence of symptoms such as chest pain and dyspnea. No intervention was necessary for most cases of pneumothorax in asymptomatic patients. The more widespread use of procedural ultrasonography may explain some discrepancies between the early^5,6 and more recent studies.^1,8–10

Several studies have demonstrated that postprocedural radiography is unnecessary unless a complication is suspected based on the patient’s symptoms or the need to demonstrate lung re-expansion.^1,4,9,10 Clinical suspicion and the patient’s symptoms are the major predictors of procedure-related pneumothorax requiring treatment with a chest tube. Otherwise, incidentally discovered pneumothorax can usually be observed and managed supportively.

Major causes of pneumothorax in patients undergoing thoracentesis are direct puncture during needle or catheter insertion, the introduction of air through the needle or catheter into the pleural cavity, and the inability of the ipsilateral lung to fully expand after drainage of a large volume of fluid, known as pneumothorax ex vacuo.⁵

Pneumothorax ex vacuo may be seen in patients with medical conditions such as endobronchial obstruction, pleural scarring from long-standing pleural effusion, and lung malignancy, all of which can impair the lung’s ability to expand after removal of a large volume of pleural fluid. It is believed that transient parenchymal pleural fistulae form if the lung cannot expand, causing air leakage into the pleural cavity.^5,8,9 Pleural manometry to monitor changes in pleural pressure and elastance can decrease the rates of pneumothorax ex vacuo in patients with the above risk factors.⁵

WHEN IS RADIOGRAPHY INDICATED AFTER THORACENTESIS?

Current literature suggests that imaging to evaluate for postprocedural complications should be done if there is suspicion of a complication, if thoracentesis required multiple attempts, if the procedure caused aspiration of air, if the patient has advanced lung disease, if the patient is scheduled to undergo thoracic radiation, if the patient is on mechanical ventilation, and after therapeutic thoracentesis if a large volume of fluid is removed.^1–10 Routine chest radiography after thoracentesis is not supported in the literature in the absence of these risk factors.

Some practitioners order chest imaging after therapeutic thoracentesis to assess for residual pleural fluid and for visualization of other abnormalities previously hidden by pleural effusion, rather than simply to exclude postprocedural pneumothorax. Alternatively, postprocedural bedside pleural ultrasonography with recording of images can be done to assess for complications and residual pleural fluid volume without exposing the patient to radiation.¹¹

Needle decompression and chest tube insertion should be considered in patients with tension pneumothorax, large pneumothorax (distance from the chest wall to the visceral pleural line of at least 2 cm), mechanical ventilation, progressing pneumothorax, and symptoms.

KEY POINTS

• Pneumothorax is a rare complication of thoracentesis when performed by a skilled operator using ultrasonographic guidance.
• Mechanisms behind the occurrence of pneumothorax are direct lung puncture, introduction of air into the pleural cavity, and pneumothorax ex vacuo.
• In asymptomatic patients, pneumothorax after thoracentesis rarely requires intervention beyond supportive care and close observation.
• Factors such as multiple thoracentesis attempts, symptoms, clinical suspicion, air aspiration during thoracentesis, presence of previous lung disease, and removal of a large volume of fluid may require postprocedural lung imaging (eg, bedside ultrasonography, radiography).

No. After thoracentesis, chest radiography or another lung imaging study should be done only if pneumothorax is suspected, if thoracentesis requires more than 1 attempt, if the patient is on mechanical ventilation or has pre-existing lung disease, or if a large volume (> 1,500 mL) of fluid is removed. Radiography is also usually not necessary after diagnostic thoracentesis in a patient breathing spontaneously. In most cases, pneumothorax found incidentally after thoracentesis does not require decompression and can be managed supportively.

WHAT ARE THE RISKS OF THORACENTESIS?

Thoracentesis is a minimally invasive procedure usually performed at the bedside that involves insertion of a needle into the pleural cavity for drainage of fluid.¹ Diagnostic thoracentesis should be done in most cases of a new pleural effusion unless the effusion is small and with a clear diagnosis, or in cases of typical heart failure.

Therapeutic thoracentesis, often called large-volume thoracentesis, aims to improve symptoms such as dyspnea attributed to the pleural effusion by removing at least 1 L of pleural fluid. The presence of active respiratory symptoms and suspicion of infected pleural effusion should lead to thoracentesis as soon as possible.

Complications of thoracentesis may be benign, such as pain and anxiety associated with the procedure and external bleeding at the site of needle insertion. Pneumothorax is the most common serious procedural complication and the principal reason to order postprocedural chest radiography.¹ Less common complications include hemothorax, re-expansion pulmonary edema, infection, subdiaphragmatic organ puncture, and procedure-related death. Bleeding complications and hemothorax are rare even in patients with underlying coagulopathy.²

Point-of-care pleural ultrasonography is now considered the standard of care to guide optimal needle location for the procedure and to exclude other conditions that can mimic pleural effusion on chest radiography, such as lung consolidation and atelectasis.³ High proficiency in the use of preprocedural point-of-care ultrasonography reduces the rate of procedural complications, though it does not eliminate the risk entirely.^3,4

Factors associated with higher rates of complications include lack of operator proficiency, poor understanding of the anatomy, poor patient positioning, poor patient cooperation with the procedure, lack of availability of bedside ultrasonography, and drainage of more than 1,500 mL of fluid. Addressing these factors has been shown to decrease the risk of pneumothorax and infection.^1–5

HOW OFTEN DOES PNEUMOTHORAX OCCUR AFTER THORACENTESIS?

Several early studies have examined the incidence of pneumothorax after thoracentesis. Lack of ultrasonography use likely explains a higher incidence of complications in early studies: rates of pneumothorax after thoracentesis without ultrasonographic guidance ranged from 5.2% to 26%.^6,7

Gervais et al⁸ analyzed thoracentesis with ultrasonographic guidance in 434 patients, 92 of whom were intubated, and reported that pneumothorax occurred in 10 patients, of whom 6 were intubated. Two of the intubated patients required chest tubes. Other studies have confirmed the low incidence of pneumothorax in patients undergoing thoracentesis, with rates such as 0.61%,¹ 5%,9 and 4%.¹⁰

The major predictor of postprocedural pneumothorax was the presence of symptoms such as chest pain and dyspnea. No intervention was necessary for most cases of pneumothorax in asymptomatic patients. The more widespread use of procedural ultrasonography may explain some discrepancies between the early^5,6 and more recent studies.^1,8–10

Several studies have demonstrated that postprocedural radiography is unnecessary unless a complication is suspected based on the patient’s symptoms or the need to demonstrate lung re-expansion.^1,4,9,10 Clinical suspicion and the patient’s symptoms are the major predictors of procedure-related pneumothorax requiring treatment with a chest tube. Otherwise, incidentally discovered pneumothorax can usually be observed and managed supportively.

Major causes of pneumothorax in patients undergoing thoracentesis are direct puncture during needle or catheter insertion, the introduction of air through the needle or catheter into the pleural cavity, and the inability of the ipsilateral lung to fully expand after drainage of a large volume of fluid, known as pneumothorax ex vacuo.⁵

Pneumothorax ex vacuo may be seen in patients with medical conditions such as endobronchial obstruction, pleural scarring from long-standing pleural effusion, and lung malignancy, all of which can impair the lung’s ability to expand after removal of a large volume of pleural fluid. It is believed that transient parenchymal pleural fistulae form if the lung cannot expand, causing air leakage into the pleural cavity.^5,8,9 Pleural manometry to monitor changes in pleural pressure and elastance can decrease the rates of pneumothorax ex vacuo in patients with the above risk factors.⁵

WHEN IS RADIOGRAPHY INDICATED AFTER THORACENTESIS?

Current literature suggests that imaging to evaluate for postprocedural complications should be done if there is suspicion of a complication, if thoracentesis required multiple attempts, if the procedure caused aspiration of air, if the patient has advanced lung disease, if the patient is scheduled to undergo thoracic radiation, if the patient is on mechanical ventilation, and after therapeutic thoracentesis if a large volume of fluid is removed.^1–10 Routine chest radiography after thoracentesis is not supported in the literature in the absence of these risk factors.

Some practitioners order chest imaging after therapeutic thoracentesis to assess for residual pleural fluid and for visualization of other abnormalities previously hidden by pleural effusion, rather than simply to exclude postprocedural pneumothorax. Alternatively, postprocedural bedside pleural ultrasonography with recording of images can be done to assess for complications and residual pleural fluid volume without exposing the patient to radiation.¹¹

Needle decompression and chest tube insertion should be considered in patients with tension pneumothorax, large pneumothorax (distance from the chest wall to the visceral pleural line of at least 2 cm), mechanical ventilation, progressing pneumothorax, and symptoms.

KEY POINTS

• Pneumothorax is a rare complication of thoracentesis when performed by a skilled operator using ultrasonographic guidance.
• Mechanisms behind the occurrence of pneumothorax are direct lung puncture, introduction of air into the pleural cavity, and pneumothorax ex vacuo.
• In asymptomatic patients, pneumothorax after thoracentesis rarely requires intervention beyond supportive care and close observation.
• Factors such as multiple thoracentesis attempts, symptoms, clinical suspicion, air aspiration during thoracentesis, presence of previous lung disease, and removal of a large volume of fluid may require postprocedural lung imaging (eg, bedside ultrasonography, radiography).

No. After thoracentesis, chest radiography or another lung imaging study should be done only if pneumothorax is suspected, if thoracentesis requires more than 1 attempt, if the patient is on mechanical ventilation or has pre-existing lung disease, or if a large volume (> 1,500 mL) of fluid is removed. Radiography is also usually not necessary after diagnostic thoracentesis in a patient breathing spontaneously. In most cases, pneumothorax found incidentally after thoracentesis does not require decompression and can be managed supportively.

WHAT ARE THE RISKS OF THORACENTESIS?

Thoracentesis is a minimally invasive procedure usually performed at the bedside that involves insertion of a needle into the pleural cavity for drainage of fluid.¹ Diagnostic thoracentesis should be done in most cases of a new pleural effusion unless the effusion is small and with a clear diagnosis, or in cases of typical heart failure.

Therapeutic thoracentesis, often called large-volume thoracentesis, aims to improve symptoms such as dyspnea attributed to the pleural effusion by removing at least 1 L of pleural fluid. The presence of active respiratory symptoms and suspicion of infected pleural effusion should lead to thoracentesis as soon as possible.

Complications of thoracentesis may be benign, such as pain and anxiety associated with the procedure and external bleeding at the site of needle insertion. Pneumothorax is the most common serious procedural complication and the principal reason to order postprocedural chest radiography.¹ Less common complications include hemothorax, re-expansion pulmonary edema, infection, subdiaphragmatic organ puncture, and procedure-related death. Bleeding complications and hemothorax are rare even in patients with underlying coagulopathy.²

Point-of-care pleural ultrasonography is now considered the standard of care to guide optimal needle location for the procedure and to exclude other conditions that can mimic pleural effusion on chest radiography, such as lung consolidation and atelectasis.³ High proficiency in the use of preprocedural point-of-care ultrasonography reduces the rate of procedural complications, though it does not eliminate the risk entirely.^3,4

Factors associated with higher rates of complications include lack of operator proficiency, poor understanding of the anatomy, poor patient positioning, poor patient cooperation with the procedure, lack of availability of bedside ultrasonography, and drainage of more than 1,500 mL of fluid. Addressing these factors has been shown to decrease the risk of pneumothorax and infection.^1–5

HOW OFTEN DOES PNEUMOTHORAX OCCUR AFTER THORACENTESIS?

Several early studies have examined the incidence of pneumothorax after thoracentesis. Lack of ultrasonography use likely explains a higher incidence of complications in early studies: rates of pneumothorax after thoracentesis without ultrasonographic guidance ranged from 5.2% to 26%.^6,7

Gervais et al⁸ analyzed thoracentesis with ultrasonographic guidance in 434 patients, 92 of whom were intubated, and reported that pneumothorax occurred in 10 patients, of whom 6 were intubated. Two of the intubated patients required chest tubes. Other studies have confirmed the low incidence of pneumothorax in patients undergoing thoracentesis, with rates such as 0.61%,¹ 5%,9 and 4%.¹⁰

The major predictor of postprocedural pneumothorax was the presence of symptoms such as chest pain and dyspnea. No intervention was necessary for most cases of pneumothorax in asymptomatic patients. The more widespread use of procedural ultrasonography may explain some discrepancies between the early^5,6 and more recent studies.^1,8–10

Several studies have demonstrated that postprocedural radiography is unnecessary unless a complication is suspected based on the patient’s symptoms or the need to demonstrate lung re-expansion.^1,4,9,10 Clinical suspicion and the patient’s symptoms are the major predictors of procedure-related pneumothorax requiring treatment with a chest tube. Otherwise, incidentally discovered pneumothorax can usually be observed and managed supportively.

Major causes of pneumothorax in patients undergoing thoracentesis are direct puncture during needle or catheter insertion, the introduction of air through the needle or catheter into the pleural cavity, and the inability of the ipsilateral lung to fully expand after drainage of a large volume of fluid, known as pneumothorax ex vacuo.⁵

Pneumothorax ex vacuo may be seen in patients with medical conditions such as endobronchial obstruction, pleural scarring from long-standing pleural effusion, and lung malignancy, all of which can impair the lung’s ability to expand after removal of a large volume of pleural fluid. It is believed that transient parenchymal pleural fistulae form if the lung cannot expand, causing air leakage into the pleural cavity.^5,8,9 Pleural manometry to monitor changes in pleural pressure and elastance can decrease the rates of pneumothorax ex vacuo in patients with the above risk factors.⁵

WHEN IS RADIOGRAPHY INDICATED AFTER THORACENTESIS?

Current literature suggests that imaging to evaluate for postprocedural complications should be done if there is suspicion of a complication, if thoracentesis required multiple attempts, if the procedure caused aspiration of air, if the patient has advanced lung disease, if the patient is scheduled to undergo thoracic radiation, if the patient is on mechanical ventilation, and after therapeutic thoracentesis if a large volume of fluid is removed.^1–10 Routine chest radiography after thoracentesis is not supported in the literature in the absence of these risk factors.

Some practitioners order chest imaging after therapeutic thoracentesis to assess for residual pleural fluid and for visualization of other abnormalities previously hidden by pleural effusion, rather than simply to exclude postprocedural pneumothorax. Alternatively, postprocedural bedside pleural ultrasonography with recording of images can be done to assess for complications and residual pleural fluid volume without exposing the patient to radiation.¹¹

Needle decompression and chest tube insertion should be considered in patients with tension pneumothorax, large pneumothorax (distance from the chest wall to the visceral pleural line of at least 2 cm), mechanical ventilation, progressing pneumothorax, and symptoms.

KEY POINTS

• Pneumothorax is a rare complication of thoracentesis when performed by a skilled operator using ultrasonographic guidance.
• Mechanisms behind the occurrence of pneumothorax are direct lung puncture, introduction of air into the pleural cavity, and pneumothorax ex vacuo.
• In asymptomatic patients, pneumothorax after thoracentesis rarely requires intervention beyond supportive care and close observation.
• Factors such as multiple thoracentesis attempts, symptoms, clinical suspicion, air aspiration during thoracentesis, presence of previous lung disease, and removal of a large volume of fluid may require postprocedural lung imaging (eg, bedside ultrasonography, radiography).

A 39-year-old woman with a history of human immunodeficiency virus (HIV) and hepatitis B virus infection was brought to the emergency department for evaluation of seizures, which had started a few days earlier. She was born and raised in a state bordering the Ohio River, an area where Histoplasma capsulatum is endemic. She denied any recent travel.

Her vital signs and neurologic examination were normal. Computed tomography of the head showed two areas of increased attenuation anterior to the frontal horns. To better characterize those lesions, magnetic resonance imaging (MRI) with contrast was done, which showed about a dozen 1-cm ring-enhancing lesions in the right cerebellum and both cerebral hemispheres (Figure 1).

Results of a complete blood cell count, metabolic profile, and chest radiography were normal. Her CD4 count was 428/μL (reference range 533–1,674) and 20% (60%–89%); her HIV viral load was 326,000 copies/mL.

She was initially treated empirically with sulfadiazine, pyrimethamine, and leukovorin for possible toxoplasmosis, which is the most common cause of ring-enhancing brain lesions in HIV patients. In the meantime, cerebrospinal fluid, blood, and urine were sent for a detailed workup for fungi, including Histoplasma. Results of the Histoplasma antibody and antigen studies of the serum, urine, and cerebrospinal fluid were positive, while cerebrospinal fluid testing for Toxoplasma by polymerase chain reaction testing was negative. Empirical treatment for toxoplasmosis was stopped and amphotericin B was started to treat disseminated histoplasmosis.

During her hospital course, she underwent brain biopsy via right frontotemporal craniotomy with resection of right frontal lesions. Pathologic study showed partially organizing abscesses with central necrosis (Figure 2), microscopy with Grocott-Gomori methenamine silver stain was positive for budding yeast forms consistent with H capsulatum (Figure 3), and special stain for acid-fast bacilli was negative for mycobacteria. Cultures of the brain biopsy specimen, blood, and cerebrospinal fluid for fungi, acid-fast bacilli, and bacteria did not reveal any growth after 28 days.

The patient was discharged home with instructions to take amphotericin B for a total of 6 weeks and then itraconazole. About 1 year later, she remained free of symptoms, although repeat MRI did not show any significant change in the size or number of histoplasmomas.

She did not comply well with her HIV treatment, and her immune status did not improve, so we decided to continue her itraconazole treatment for more than 1 year.

CEREBRAL HISTOPLASMOMA

The term “histoplasmoma” was introduced by Shapiro et al¹ in 1955, when they first described numerous focal areas of softening, up to 1 cm in diameter, scattered throughout the brain at autopsy in a 41-year-old man who had died of disseminated histoplasmosis. They coined the word to describe these discrete areas of necrosis that might resemble tumors on the basis of their size, location, and capability of causing increased intracranial pressure.

Central nervous system involvement can either be a manifestation of disseminated disease or present as an isolated illness.² It occurs in 5% to 10% of cases of disseminated histoplasmosis.³ Histoplasmosis of the central nervous system can have different manifestations; the most common presentation is chronic meningitis.⁴

Laboratory diagnosis is based on detecting H capsulatum antigen and antibody in the urine, blood, and cerebrospinal fluid. Tissue biopsy (histopathology) as well as cultures of tissue samples or body fluids may also establish the diagnosis.⁴

Toxoplasmosis and primary central nervous system lymphoma are the most common causes of brain ring-enhancing lesions in HIV patients in developed countries, while in the developing world neurocysticercosis and tuberculomas are more common.^5,6 Much less common causes include brain abscesses secondary to bacterial infections (pyogenic abscess),⁷ cryptococcomas,⁸ syphilitic cerebral gummata,⁹ primary brain tumors (gliomas), and metastases.¹⁰

Compared with other forms of the disease, histoplasmosis of the central nervous system has higher rates of treatment failure and relapse, so treatment should be prolonged and aggressive.^2,3 The cure rate with amphotericin B ranges from 33% to 61%, and higher doses produce better response rates.³

Current treatment recommendations are based on 2007 guidelines of the Infectious Diseases Society of America.¹¹ Liposomal amphotericin B is the drug of choice because it achieves higher concentrations in the central nervous system than other drugs and is less toxic. It is given for 4 to 6 weeks, followed by itraconazole for at least 1 year and until the cerebrospinal fluid Histoplasma antigen test is negative and other cerebrospinal fluid abnormalities are resolved.

In patients who have primary disseminated histoplasmosis that includes the central nervous system, itraconazole can be given for more than 1 year or until immune recovery is achieved—or lifelong if necessary.^2,12 Long-term suppressive antifungal therapy also should be considered in patients for whom appropriate initial therapy fails.²

Nephrotoxicity (acute kidney injury, hypokalemia, and hypomagnesemia), infusion-related drug reactions, and rash are among the well-described side effects of amphotericin B. Maintenance of intravascular volume and replacement of electrolytes should be an integral part of the amphotericin B treatment regimen.¹³

TAKE-AWAY POINTS

• Histoplasmomas should be considered in the differential diagnosis of ring-enhancing lesions of the central nervous system, along with toxoplasmosis and primary central nervous system lymphoma. This will allow timely initiation of the diagnostic workup, avoiding unnecessary and potentially risky interventions and delays in starting targeted antifungal therapy.
• There is no single gold standard test for central nervous system histoplasmosis. Rather, the final diagnosis is based on the combination of clinical, laboratory, and radiologic findings.

Acknowledgment: Library research assistance provided by HSHS St. John’s Hospital Health Sciences Library staff.

A 39-year-old woman with a history of human immunodeficiency virus (HIV) and hepatitis B virus infection was brought to the emergency department for evaluation of seizures, which had started a few days earlier. She was born and raised in a state bordering the Ohio River, an area where Histoplasma capsulatum is endemic. She denied any recent travel.

Her vital signs and neurologic examination were normal. Computed tomography of the head showed two areas of increased attenuation anterior to the frontal horns. To better characterize those lesions, magnetic resonance imaging (MRI) with contrast was done, which showed about a dozen 1-cm ring-enhancing lesions in the right cerebellum and both cerebral hemispheres (Figure 1).

Results of a complete blood cell count, metabolic profile, and chest radiography were normal. Her CD4 count was 428/μL (reference range 533–1,674) and 20% (60%–89%); her HIV viral load was 326,000 copies/mL.

She was initially treated empirically with sulfadiazine, pyrimethamine, and leukovorin for possible toxoplasmosis, which is the most common cause of ring-enhancing brain lesions in HIV patients. In the meantime, cerebrospinal fluid, blood, and urine were sent for a detailed workup for fungi, including Histoplasma. Results of the Histoplasma antibody and antigen studies of the serum, urine, and cerebrospinal fluid were positive, while cerebrospinal fluid testing for Toxoplasma by polymerase chain reaction testing was negative. Empirical treatment for toxoplasmosis was stopped and amphotericin B was started to treat disseminated histoplasmosis.

During her hospital course, she underwent brain biopsy via right frontotemporal craniotomy with resection of right frontal lesions. Pathologic study showed partially organizing abscesses with central necrosis (Figure 2), microscopy with Grocott-Gomori methenamine silver stain was positive for budding yeast forms consistent with H capsulatum (Figure 3), and special stain for acid-fast bacilli was negative for mycobacteria. Cultures of the brain biopsy specimen, blood, and cerebrospinal fluid for fungi, acid-fast bacilli, and bacteria did not reveal any growth after 28 days.

The patient was discharged home with instructions to take amphotericin B for a total of 6 weeks and then itraconazole. About 1 year later, she remained free of symptoms, although repeat MRI did not show any significant change in the size or number of histoplasmomas.

She did not comply well with her HIV treatment, and her immune status did not improve, so we decided to continue her itraconazole treatment for more than 1 year.

CEREBRAL HISTOPLASMOMA

The term “histoplasmoma” was introduced by Shapiro et al¹ in 1955, when they first described numerous focal areas of softening, up to 1 cm in diameter, scattered throughout the brain at autopsy in a 41-year-old man who had died of disseminated histoplasmosis. They coined the word to describe these discrete areas of necrosis that might resemble tumors on the basis of their size, location, and capability of causing increased intracranial pressure.

Central nervous system involvement can either be a manifestation of disseminated disease or present as an isolated illness.² It occurs in 5% to 10% of cases of disseminated histoplasmosis.³ Histoplasmosis of the central nervous system can have different manifestations; the most common presentation is chronic meningitis.⁴

Laboratory diagnosis is based on detecting H capsulatum antigen and antibody in the urine, blood, and cerebrospinal fluid. Tissue biopsy (histopathology) as well as cultures of tissue samples or body fluids may also establish the diagnosis.⁴

Toxoplasmosis and primary central nervous system lymphoma are the most common causes of brain ring-enhancing lesions in HIV patients in developed countries, while in the developing world neurocysticercosis and tuberculomas are more common.^5,6 Much less common causes include brain abscesses secondary to bacterial infections (pyogenic abscess),⁷ cryptococcomas,⁸ syphilitic cerebral gummata,⁹ primary brain tumors (gliomas), and metastases.¹⁰

Compared with other forms of the disease, histoplasmosis of the central nervous system has higher rates of treatment failure and relapse, so treatment should be prolonged and aggressive.^2,3 The cure rate with amphotericin B ranges from 33% to 61%, and higher doses produce better response rates.³

Current treatment recommendations are based on 2007 guidelines of the Infectious Diseases Society of America.¹¹ Liposomal amphotericin B is the drug of choice because it achieves higher concentrations in the central nervous system than other drugs and is less toxic. It is given for 4 to 6 weeks, followed by itraconazole for at least 1 year and until the cerebrospinal fluid Histoplasma antigen test is negative and other cerebrospinal fluid abnormalities are resolved.

In patients who have primary disseminated histoplasmosis that includes the central nervous system, itraconazole can be given for more than 1 year or until immune recovery is achieved—or lifelong if necessary.^2,12 Long-term suppressive antifungal therapy also should be considered in patients for whom appropriate initial therapy fails.²

Nephrotoxicity (acute kidney injury, hypokalemia, and hypomagnesemia), infusion-related drug reactions, and rash are among the well-described side effects of amphotericin B. Maintenance of intravascular volume and replacement of electrolytes should be an integral part of the amphotericin B treatment regimen.¹³

TAKE-AWAY POINTS

• Histoplasmomas should be considered in the differential diagnosis of ring-enhancing lesions of the central nervous system, along with toxoplasmosis and primary central nervous system lymphoma. This will allow timely initiation of the diagnostic workup, avoiding unnecessary and potentially risky interventions and delays in starting targeted antifungal therapy.
• There is no single gold standard test for central nervous system histoplasmosis. Rather, the final diagnosis is based on the combination of clinical, laboratory, and radiologic findings.

Acknowledgment: Library research assistance provided by HSHS St. John’s Hospital Health Sciences Library staff.

A 39-year-old woman with a history of human immunodeficiency virus (HIV) and hepatitis B virus infection was brought to the emergency department for evaluation of seizures, which had started a few days earlier. She was born and raised in a state bordering the Ohio River, an area where Histoplasma capsulatum is endemic. She denied any recent travel.

Her vital signs and neurologic examination were normal. Computed tomography of the head showed two areas of increased attenuation anterior to the frontal horns. To better characterize those lesions, magnetic resonance imaging (MRI) with contrast was done, which showed about a dozen 1-cm ring-enhancing lesions in the right cerebellum and both cerebral hemispheres (Figure 1).

Results of a complete blood cell count, metabolic profile, and chest radiography were normal. Her CD4 count was 428/μL (reference range 533–1,674) and 20% (60%–89%); her HIV viral load was 326,000 copies/mL.

She was initially treated empirically with sulfadiazine, pyrimethamine, and leukovorin for possible toxoplasmosis, which is the most common cause of ring-enhancing brain lesions in HIV patients. In the meantime, cerebrospinal fluid, blood, and urine were sent for a detailed workup for fungi, including Histoplasma. Results of the Histoplasma antibody and antigen studies of the serum, urine, and cerebrospinal fluid were positive, while cerebrospinal fluid testing for Toxoplasma by polymerase chain reaction testing was negative. Empirical treatment for toxoplasmosis was stopped and amphotericin B was started to treat disseminated histoplasmosis.

During her hospital course, she underwent brain biopsy via right frontotemporal craniotomy with resection of right frontal lesions. Pathologic study showed partially organizing abscesses with central necrosis (Figure 2), microscopy with Grocott-Gomori methenamine silver stain was positive for budding yeast forms consistent with H capsulatum (Figure 3), and special stain for acid-fast bacilli was negative for mycobacteria. Cultures of the brain biopsy specimen, blood, and cerebrospinal fluid for fungi, acid-fast bacilli, and bacteria did not reveal any growth after 28 days.

The patient was discharged home with instructions to take amphotericin B for a total of 6 weeks and then itraconazole. About 1 year later, she remained free of symptoms, although repeat MRI did not show any significant change in the size or number of histoplasmomas.

She did not comply well with her HIV treatment, and her immune status did not improve, so we decided to continue her itraconazole treatment for more than 1 year.

CEREBRAL HISTOPLASMOMA

The term “histoplasmoma” was introduced by Shapiro et al¹ in 1955, when they first described numerous focal areas of softening, up to 1 cm in diameter, scattered throughout the brain at autopsy in a 41-year-old man who had died of disseminated histoplasmosis. They coined the word to describe these discrete areas of necrosis that might resemble tumors on the basis of their size, location, and capability of causing increased intracranial pressure.

Central nervous system involvement can either be a manifestation of disseminated disease or present as an isolated illness.² It occurs in 5% to 10% of cases of disseminated histoplasmosis.³ Histoplasmosis of the central nervous system can have different manifestations; the most common presentation is chronic meningitis.⁴

Laboratory diagnosis is based on detecting H capsulatum antigen and antibody in the urine, blood, and cerebrospinal fluid. Tissue biopsy (histopathology) as well as cultures of tissue samples or body fluids may also establish the diagnosis.⁴

Toxoplasmosis and primary central nervous system lymphoma are the most common causes of brain ring-enhancing lesions in HIV patients in developed countries, while in the developing world neurocysticercosis and tuberculomas are more common.^5,6 Much less common causes include brain abscesses secondary to bacterial infections (pyogenic abscess),⁷ cryptococcomas,⁸ syphilitic cerebral gummata,⁹ primary brain tumors (gliomas), and metastases.¹⁰

Compared with other forms of the disease, histoplasmosis of the central nervous system has higher rates of treatment failure and relapse, so treatment should be prolonged and aggressive.^2,3 The cure rate with amphotericin B ranges from 33% to 61%, and higher doses produce better response rates.³

Current treatment recommendations are based on 2007 guidelines of the Infectious Diseases Society of America.¹¹ Liposomal amphotericin B is the drug of choice because it achieves higher concentrations in the central nervous system than other drugs and is less toxic. It is given for 4 to 6 weeks, followed by itraconazole for at least 1 year and until the cerebrospinal fluid Histoplasma antigen test is negative and other cerebrospinal fluid abnormalities are resolved.

In patients who have primary disseminated histoplasmosis that includes the central nervous system, itraconazole can be given for more than 1 year or until immune recovery is achieved—or lifelong if necessary.^2,12 Long-term suppressive antifungal therapy also should be considered in patients for whom appropriate initial therapy fails.²

Nephrotoxicity (acute kidney injury, hypokalemia, and hypomagnesemia), infusion-related drug reactions, and rash are among the well-described side effects of amphotericin B. Maintenance of intravascular volume and replacement of electrolytes should be an integral part of the amphotericin B treatment regimen.¹³

TAKE-AWAY POINTS

• Histoplasmomas should be considered in the differential diagnosis of ring-enhancing lesions of the central nervous system, along with toxoplasmosis and primary central nervous system lymphoma. This will allow timely initiation of the diagnostic workup, avoiding unnecessary and potentially risky interventions and delays in starting targeted antifungal therapy.
• There is no single gold standard test for central nervous system histoplasmosis. Rather, the final diagnosis is based on the combination of clinical, laboratory, and radiologic findings.

Acknowledgment: Library research assistance provided by HSHS St. John’s Hospital Health Sciences Library staff.

To the Editor: We read the IM Board Review article by Hanouneh et al in the February issue of the Journal with great interest.¹ The authors described an interesting case of a young woman presenting with what initially seemed to be jaundice of acute onset, with rapid progression to acute encephalopathy and worsening liver failure. The patient was eventually diagnosed with fulminant Wilson disease and, thankfully, underwent successful liver transplant. We thank the authors for their in-depth review of the common causes of acute liver failure, the general approach to management, and the tailored treatment of Wilson disease in such settings.

However, we believe that several aspects merit further attention. First, on initial presentation and investigation, it would have been important to consider cholestatic hepatobiliary pathologic processes (eg, choledocholithiasis, cholangitis, primary biliary cirrhosis, primary sclerosing cholangitis), given the characteristic liver panel results.

Second, the authors rightly pointed out that hemolytic anemia is common in patients with acute liver failure secondary to Wilson disease. However, it is important to keep in mind that additional testing should include Coombs testing (typically negative in Wilson disease) and examination of the peripheral smear to exclude other etiologies, since such conditions as thrombotic thrombocytopenic purpura may present with multiorgan failure as well.²

Third, the authors report that Kayser-Fleischer rings are pathognomonic for Wilson disease. However, many reports in peer-reviewed medical journals suggest that this may not be the case and the overall clinical picture should be
considered.³

Fourth, while the authors focus their attention on liver transplant, several other treatments deserve mentioning. We agree that liver transplant is considered the only lifesaving treatment. But in certain situations, molecular absorbent recirculation systems and hemodialysis may provide temporary support while awaiting transportation to a liver transplant center or actual liver transplant.⁴

To the Editor: We read the IM Board Review article by Hanouneh et al in the February issue of the Journal with great interest.¹ The authors described an interesting case of a young woman presenting with what initially seemed to be jaundice of acute onset, with rapid progression to acute encephalopathy and worsening liver failure. The patient was eventually diagnosed with fulminant Wilson disease and, thankfully, underwent successful liver transplant. We thank the authors for their in-depth review of the common causes of acute liver failure, the general approach to management, and the tailored treatment of Wilson disease in such settings.

However, we believe that several aspects merit further attention. First, on initial presentation and investigation, it would have been important to consider cholestatic hepatobiliary pathologic processes (eg, choledocholithiasis, cholangitis, primary biliary cirrhosis, primary sclerosing cholangitis), given the characteristic liver panel results.

Second, the authors rightly pointed out that hemolytic anemia is common in patients with acute liver failure secondary to Wilson disease. However, it is important to keep in mind that additional testing should include Coombs testing (typically negative in Wilson disease) and examination of the peripheral smear to exclude other etiologies, since such conditions as thrombotic thrombocytopenic purpura may present with multiorgan failure as well.²

Third, the authors report that Kayser-Fleischer rings are pathognomonic for Wilson disease. However, many reports in peer-reviewed medical journals suggest that this may not be the case and the overall clinical picture should be
considered.³

Fourth, while the authors focus their attention on liver transplant, several other treatments deserve mentioning. We agree that liver transplant is considered the only lifesaving treatment. But in certain situations, molecular absorbent recirculation systems and hemodialysis may provide temporary support while awaiting transportation to a liver transplant center or actual liver transplant.⁴

To the Editor: We read the IM Board Review article by Hanouneh et al in the February issue of the Journal with great interest.¹ The authors described an interesting case of a young woman presenting with what initially seemed to be jaundice of acute onset, with rapid progression to acute encephalopathy and worsening liver failure. The patient was eventually diagnosed with fulminant Wilson disease and, thankfully, underwent successful liver transplant. We thank the authors for their in-depth review of the common causes of acute liver failure, the general approach to management, and the tailored treatment of Wilson disease in such settings.

However, we believe that several aspects merit further attention. First, on initial presentation and investigation, it would have been important to consider cholestatic hepatobiliary pathologic processes (eg, choledocholithiasis, cholangitis, primary biliary cirrhosis, primary sclerosing cholangitis), given the characteristic liver panel results.

Second, the authors rightly pointed out that hemolytic anemia is common in patients with acute liver failure secondary to Wilson disease. However, it is important to keep in mind that additional testing should include Coombs testing (typically negative in Wilson disease) and examination of the peripheral smear to exclude other etiologies, since such conditions as thrombotic thrombocytopenic purpura may present with multiorgan failure as well.²

Third, the authors report that Kayser-Fleischer rings are pathognomonic for Wilson disease. However, many reports in peer-reviewed medical journals suggest that this may not be the case and the overall clinical picture should be
considered.³

Fourth, while the authors focus their attention on liver transplant, several other treatments deserve mentioning. We agree that liver transplant is considered the only lifesaving treatment. But in certain situations, molecular absorbent recirculation systems and hemodialysis may provide temporary support while awaiting transportation to a liver transplant center or actual liver transplant.⁴