American Board of Family Medicine (ABFM) Practice Exam

What is the next step when suspecting asthma in a 15-year-old boy with nighttime cough and wheezing?

1. Treat empirically with a short-acting beta-agonist

2. Perform spirometry

3. Order radiologic testing

4. Start an inhaled corticosteroid

The correct answer is: Perform spirometry

The correct approach when you suspect asthma in a 15-year-old boy presenting with nighttime cough and wheezing is to perform spirometry. Spirometry is a key diagnostic tool that measures lung function and helps in assessing airflow obstruction, which is characteristic of asthma. This test allows the clinician to objectively evaluate the degree of airway obstruction, assess the reversibility of bronchoconstriction with bronchodilators, and monitor lung function over time. In the case of asthma, specific findings on spirometry include a reduced forced expiratory volume in one second (FEV1) and a reduced FEV1/FVC ratio, indicating obstructive lung disease. If the results demonstrate reversible airflow obstruction after the administration of a short-acting bronchodilator, it supports the diagnosis of asthma. While starting treatment or referring for imaging might seem reasonable, the important first step in confirming a suspicion of asthma, particularly in a setting with possible confounding conditions, is to establish a diagnosis through objective testing rather than starting treatment before diagnosis or exploring unintended pathways.