Pneumocystis carinii pneumonia presenting as asthma: increased bronchial hyperresponsiveness in Pneumocystis carinii pneumonia.

Two male patients presented with clinical and laboratory findings consistent with typical bronchial asthma and subsequently developed Pneumocystis carinii pneumonia (PCP). Only on subsequent questioning did both admit to homosexuality and behavior associated with a high risk of HIV-infection. In order to determine how frequently reversible airway obstruction is seen in patients with PCP, we measured peak expiratory flow rates (PEFR) before and after bronchodilator administration in 37 of these patients. Initial PEFR measurements revealed a significant decrease in PEFR (< 80% predicted) in 84%, with 54% of these exhibiting a significant bronchodilator response (> or = 15% increase). For comparison, peak flow measurements were made in a control group of 31 HIV-infected patients without acute PCP, divided between those with asymptomatic HIV-infection, AIDS-related complex (ARC), and AIDS, (including patients with previous PCP). Only 23% of these individuals had low PEFR, and only 3% exhibited bronchodilator responses. In order to confirm the existence of bronchial hyperreactivity in patients with PCP, another 16 patients with PCP were tested by methacholine bronchial challenge and 50% were found to have positive responses. These findings suggest that both reversible airway obstruction and airway hyperreactivity are found in association with acute PCP and that as a result some patients with PCP may present with symptoms of asthma. It is important for physicians to have a high degree of suspicion to avoid missing a diagnosis of PCP in a patient presenting with apparent asthma.