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NEW ORLEANS – Kyle I. Happel, MD, said at the annual meeting of the American College of Physicians.
“Asthma is a disease whose symptoms are caused by variable airflow obstruction. It varies throughout the day, usually, and certainly by the week or by the month. I want you to think about the variability of a patient’s disease symptoms in forming your index of suspicion for this disease,” urged Dr. Happel, of the section of pulmonary, critical care, and allergy/immunology at Louisiana State University Medical Center in New Orleans.
These phenomena occur often. In a Canadian multicenter study of more than 700 patients with a history of physician-diagnosed asthma within the past 5 years, current asthma was ruled out in fully 33% of them on the basis of no deterioration of asthma symptoms, no evidence of reversible airway obstruction, and no bronchial hyperresponsiveness after all asthma drugs were tapered off (JAMA. 2017 Jan 17;317[3]:269-79).
Wheezing is the most specific symptom of asthma, although it is not, in fact, terribly specific. In descending order, the next most specific symptoms are breathlessness, chest tightness, and cough.
The top seven diseases that mimic asthma symptoms are chronic obstructive pulmonary disease, rhinosinusitis, heart failure with preserved or reduced ejection fraction, gastroesophageal reflux disease, angina, anxiety, and vocal cord dysfunction syndrome.
Strike two for an asthma diagnosis is a patient’s report that albuterol doesn’t improve the symptoms. That definitely raises questions about the diagnosis.
“Most asthmatics get symptomatic relief from their disease,” Dr. Happel observed.
And, if there is no indication in the patient’s chart that the asthma diagnosis was based upon demonstration of airflow obstruction on spirometry, the diagnosis is thrown further into doubt. In the recent Canadian study, patients who didn’t undergo pulmonary function testing (PFT) to establish airflow limitation at their time of diagnosis were significantly less likely to have current asthma.
“I would strongly suggest everyone with the diagnosis of asthma get spirometry with bronchodilator testing,” Dr. Happel said. “Good-quality PFTs are critical in forming a solid diagnosis of asthma.”
In a patient who has symptoms consistent with asthma, a 200-cc and 12% or more improvement in forced expiratory volume in 1 second (FEV1) in response to bronchodilator challenge is supportive of the diagnosis. However, absence of reversible airway obstruction doesn’t exclude the possibility of asthma.
In the setting of low to-moderate clinical suspicion of asthma plus no demonstrable obstruction on spirometry, Dr. Happel recommends moving on to bronchial hyperreactivity testing via a methacholine challenge.
“The beauty of a methacholine challenge is that is has a high negative predictive value to help exclude the diagnosis of asthma, particularly in people who are having symptoms suggestive of asthma,” Dr. Happel explained. “If it takes more than 8 mg/mL of methacholine to elicit a 20% or greater decrease in FEV1, it’s probably something else. It’s not a particularly specific test, though; you can get false positives from a methacholine challenge.”
NEW ORLEANS – Kyle I. Happel, MD, said at the annual meeting of the American College of Physicians.
“Asthma is a disease whose symptoms are caused by variable airflow obstruction. It varies throughout the day, usually, and certainly by the week or by the month. I want you to think about the variability of a patient’s disease symptoms in forming your index of suspicion for this disease,” urged Dr. Happel, of the section of pulmonary, critical care, and allergy/immunology at Louisiana State University Medical Center in New Orleans.
These phenomena occur often. In a Canadian multicenter study of more than 700 patients with a history of physician-diagnosed asthma within the past 5 years, current asthma was ruled out in fully 33% of them on the basis of no deterioration of asthma symptoms, no evidence of reversible airway obstruction, and no bronchial hyperresponsiveness after all asthma drugs were tapered off (JAMA. 2017 Jan 17;317[3]:269-79).
Wheezing is the most specific symptom of asthma, although it is not, in fact, terribly specific. In descending order, the next most specific symptoms are breathlessness, chest tightness, and cough.
The top seven diseases that mimic asthma symptoms are chronic obstructive pulmonary disease, rhinosinusitis, heart failure with preserved or reduced ejection fraction, gastroesophageal reflux disease, angina, anxiety, and vocal cord dysfunction syndrome.
Strike two for an asthma diagnosis is a patient’s report that albuterol doesn’t improve the symptoms. That definitely raises questions about the diagnosis.
“Most asthmatics get symptomatic relief from their disease,” Dr. Happel observed.
And, if there is no indication in the patient’s chart that the asthma diagnosis was based upon demonstration of airflow obstruction on spirometry, the diagnosis is thrown further into doubt. In the recent Canadian study, patients who didn’t undergo pulmonary function testing (PFT) to establish airflow limitation at their time of diagnosis were significantly less likely to have current asthma.
“I would strongly suggest everyone with the diagnosis of asthma get spirometry with bronchodilator testing,” Dr. Happel said. “Good-quality PFTs are critical in forming a solid diagnosis of asthma.”
In a patient who has symptoms consistent with asthma, a 200-cc and 12% or more improvement in forced expiratory volume in 1 second (FEV1) in response to bronchodilator challenge is supportive of the diagnosis. However, absence of reversible airway obstruction doesn’t exclude the possibility of asthma.
In the setting of low to-moderate clinical suspicion of asthma plus no demonstrable obstruction on spirometry, Dr. Happel recommends moving on to bronchial hyperreactivity testing via a methacholine challenge.
“The beauty of a methacholine challenge is that is has a high negative predictive value to help exclude the diagnosis of asthma, particularly in people who are having symptoms suggestive of asthma,” Dr. Happel explained. “If it takes more than 8 mg/mL of methacholine to elicit a 20% or greater decrease in FEV1, it’s probably something else. It’s not a particularly specific test, though; you can get false positives from a methacholine challenge.”
NEW ORLEANS – Kyle I. Happel, MD, said at the annual meeting of the American College of Physicians.
“Asthma is a disease whose symptoms are caused by variable airflow obstruction. It varies throughout the day, usually, and certainly by the week or by the month. I want you to think about the variability of a patient’s disease symptoms in forming your index of suspicion for this disease,” urged Dr. Happel, of the section of pulmonary, critical care, and allergy/immunology at Louisiana State University Medical Center in New Orleans.
These phenomena occur often. In a Canadian multicenter study of more than 700 patients with a history of physician-diagnosed asthma within the past 5 years, current asthma was ruled out in fully 33% of them on the basis of no deterioration of asthma symptoms, no evidence of reversible airway obstruction, and no bronchial hyperresponsiveness after all asthma drugs were tapered off (JAMA. 2017 Jan 17;317[3]:269-79).
Wheezing is the most specific symptom of asthma, although it is not, in fact, terribly specific. In descending order, the next most specific symptoms are breathlessness, chest tightness, and cough.
The top seven diseases that mimic asthma symptoms are chronic obstructive pulmonary disease, rhinosinusitis, heart failure with preserved or reduced ejection fraction, gastroesophageal reflux disease, angina, anxiety, and vocal cord dysfunction syndrome.
Strike two for an asthma diagnosis is a patient’s report that albuterol doesn’t improve the symptoms. That definitely raises questions about the diagnosis.
“Most asthmatics get symptomatic relief from their disease,” Dr. Happel observed.
And, if there is no indication in the patient’s chart that the asthma diagnosis was based upon demonstration of airflow obstruction on spirometry, the diagnosis is thrown further into doubt. In the recent Canadian study, patients who didn’t undergo pulmonary function testing (PFT) to establish airflow limitation at their time of diagnosis were significantly less likely to have current asthma.
“I would strongly suggest everyone with the diagnosis of asthma get spirometry with bronchodilator testing,” Dr. Happel said. “Good-quality PFTs are critical in forming a solid diagnosis of asthma.”
In a patient who has symptoms consistent with asthma, a 200-cc and 12% or more improvement in forced expiratory volume in 1 second (FEV1) in response to bronchodilator challenge is supportive of the diagnosis. However, absence of reversible airway obstruction doesn’t exclude the possibility of asthma.
In the setting of low to-moderate clinical suspicion of asthma plus no demonstrable obstruction on spirometry, Dr. Happel recommends moving on to bronchial hyperreactivity testing via a methacholine challenge.
“The beauty of a methacholine challenge is that is has a high negative predictive value to help exclude the diagnosis of asthma, particularly in people who are having symptoms suggestive of asthma,” Dr. Happel explained. “If it takes more than 8 mg/mL of methacholine to elicit a 20% or greater decrease in FEV1, it’s probably something else. It’s not a particularly specific test, though; you can get false positives from a methacholine challenge.”
REPORTING FROM ACP INTERNAL MEDICINE