Methacholine Challenge Test
asthma, bronchoprovocation testing, diagnosis, bronchoconstriction
Medicine and Health Sciences | Pulmonology | Respiratory Tract Diseases
Asthma has historically been challenging to diagnose due to the non-specific nature of symptoms characteristic of the disease. Bronchoprovocation testing is a useful method to evaluate airway hyperresponsiveness and establish an initial diagnosis. Also, bronchoprovocation testing can be used to quantify the severity of airway dysfunction in patients with asthma. Methacholine challenge testing is the most common form of bronchoprovocation testing, utilizing the longer-acting acetylcholine derivative methacholine to induce bronchoconstriction. Direct bronchial challenge testing, chemically triggering airway smooth muscle receptors. The dose or concentration is escalated in small increments while monitoring airway hyperreactivity, via the resultant decreased forced expiratory volume in one second (FEV1), recording the provocative dose (PD20) or concentration (PC20) resulting in 20% decrease in FEV1 in a positive test. Methacholine is preferable to other pharmacologic bronchoprovocation agents, such as histamine, due to its limited systemic side effects.
Publisher or Conference
Sayeedi I, Widrich J. Methacholine Challenge Test. [Updated 2019 Nov 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK547716/