- METHACHOLINE INHALATION CHALLENGE: This test is one of the most widely utilized bronchial challenges and is performed to determine if a patient will react with asthma symptoms when challenged. The test is painless and consists of a series of breathing treatments and blowing tests.
The patient will inhale small amounts of a medication mist called methacholine. Each inhalation treatment is followed by a brief physical exam (listening to the lungs) and a blowing test (also called spirometry). If asthma symptoms are seen during this challenge, then the diagnosis of asthma is confirmed. If asthma symptoms are seen, these symptoms will be treated and reversed immediately. Although the goal of the test is to demonstrate asthma, the symptoms seen are usually very mild and do not persist and are not dangerous. This test will show airway hyperresponsiveness which is one of the hallmark features of asthma. Methacholine challenge testing may also be an appropriate way to evaluate the possibility of occupational asthma. Finally, the methacholine challenge may be a test that is required of someone wanting to enter a branch of the armed forces but has a history of lower respiratory symptoms such as cough, wheezing, or shortness of breath.