Thoracic Society Criteria Research Articles

Nontubercular Mycobacterial Pulmonary Infection in Immunocompetent Men

Nontubercular mycobacteria (NTM) are increasingly recognized to cause lung disease in immunocompetent patients. We studied the occurrence of pulmonary infection due to NTM in immunocompetent men. We retrospectively analyzed all sputum mycobacterial cultures at our institution over a 5-year period. Charts were reviewed to identify patients who met the American Thoracic Society's criteria for mycobacterial pulmonary infection. From the 7,380 sputum mycobacterial cultures obtained, 46 male patients had NTM identified. Forty-two patients were immunocompetent. Five of these patients were found to have NTM--2 with Mycobacterium kansasii, 2 with Mycobacterium avium-intracellulare, and 1 with Mycobacterium gordonae. All 5 patients responded to antimycobacterial therapy. Twelve percent of our population of immunocompetent men from whom NTM were isolated from sputum were infected. This study should alert the clinician that NTM cause treatable pulmonary disease in immunocompetent men.

Methacholine Challenge Test

Methacholine challenge has been proposed as a diagnostic test in situations where clinical asthma is suspected but reversible airway obstruction cannot be demonstrated spirometrically. Methacholine challenge was used in 14 patients with suspected asthma and five normal controls. Eight individuals (six patients and two controls) had a reduction in the forced expiratory volume at 1 s (FEV1) of 20% or more with 100 inhalation units (IUs) of methacholine; seven additional individuals (six patients and one control) met one or more of the American Thoracic Society's criteria for a positive bronchoprovocation test; and four individuals (two patients and two controls) were not sensitive to methacholine by any criteria. The diagnosis of asthma can be excluded if methacholine does not induce reversible obstruction. However, provocation of reversible obstruction with methacholine is not specific for asthma. More stringent criteria, such as reduction of FEV1 by 20% by 20 IUs of methacholine, would be less sensitive but more specific for asthma.