methacholine challenge test


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methacholine challenge test

a test that involves the inhalation of increasing concentrations of methacholine, a potent bronchoconstrictor, in patients with possible bronchial hyperreactivity; usually performed when a diagnosis of asthma or bronchospastic lung disease is not clinically obvious.

methacholine challenge test

(mĕth″ă-kō′lĭn)
A test for airway hyperresponsiveness, e.g., asthma or occupational asthma, in which a person is given various dilutions of the drug methacholine hydrochloride to inhale, after which spirometric measurements are taken. Decreases in the forced expiratory volume in the first second of expiration of 20% or more or decreases in specific conductance of 35% or more are indicative of airway hyper-responsiveness.
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We found that the repeatability of IOS parameters at all frequencies was comparable to that when using spirometry for the methacholine challenge test and that reactance had better repeatability than resistance.
Looking beyond acute therapy, a methacholine challenge test is an option, although many physicians might opt instead to simply treat the child empirically for asthma, Dr.
Useful diagnostic studies included an ECG showing signs of cor pulmonale, pre- and post-bronchodilator evidence of reversible airway obstruction (greater than 10% change), decreased [FEV.sub.1], a positive (10% decrease in [FEV.sub.1] methacholine challenge test, and asthmatic symptoms associated with eosinophilia in blood or sputum.
A methacholine challenge test was not performed because of the coexisting paroxysmal atrial fibrillation.
A methacholine challenge test was performed and was equivocal [the cumulative dose of methacholine (in milligrams) that causes a 20% fall in [FEV.sub.1] = 25 mg/mL methacholine].