Bronchodilator responsiveness following a negative methacholine challenge test.

Asthma is a complex disease of airway inflammation, which results in airway remodeling and hyper-responsiveness.1 Because asthma-related symptoms are not specific to asthma, diagnosis requires objective data from pulmonary function tests (PFT). Bronchodilator responsiveness and airway responsiveness to provocational stimuli (eg, methacholine, dry-gas hyperpnea) help establish the diagnosis of asthma.1 This report describes a patient who had several asthma risk factors and marked responsiveness to inhaled bronchodilators, but no airway responsiveness to methacholine inhalation.