A 28-year-old man comes to the clinic due to a nonproductive cough and chest tightness for the past 3 months. The cough is most prominent in the early morning when he jogs but also occurs at night. He has had no recent nasal symptoms, fever, malaise, or weight loss. He stopped smoking 3 years ago but had smoked half a pack a day for 5 years. He lives with his wife and 2 children and exercises regularly. He works as a technician for an air conditioning-repair company in Philadelphia. Temperature is 36.7 C (98.1 F), blood pressure is 130/80 mm Hg, pulse is 84/min, and respirations are 14/min. Oxygen saturation is 97% on room air. BMI is 26 kg/m². There is no jugular venous distension and no pharyngeal erythema or exudates. No wheezes or rhonchi are heard in either lung. During the examination, coughing was induced when the patient was asked to do a forced expiration. Cardiac examination reveals normal heart sounds. The abdomen is soft and nontender; no masses are felt. There is no peripheral edema. What is the cause of this patient's persistent cough?

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Quizplus · Accepted Answer

Explanation: This patient's cough is most likely due to asthma. Although most patients are diagnosed during childhood, this disease can present at any age. Patients typically have intermittent wheezing and shortness of breath; however, a subset of patients instead has a chronic nonproductive cough as the predominant symptom, a condition termed cough-variant asthma. The cough is typically triggered by exercise (especially in cold temperatures) or forced expiration and commonly occurs at night. Accompanying chest tightness is often present. Allergens (eg, dust mites, mold) are also common triggers; this patient's work in air conditioning repair likely leads to frequent allergen exposure. Wheezing and rhonchi are typically absent on physical examination in patients with cough-variant asthma. The diagnosis is typically made by a combination of clinical presentation and pulmonary function testing that demonstrates inducible airway obstruction (eg, positive methacholine challenge). Treatment is essentially the same as for classic asthma and takes into account symptom severity to determine the appropriate level of initial therapy. In some patients with cough that is refractory to bronchodilators and inhaled corticosteroids, leukotriene receptor antagonists (eg, montelukast) have shown efficacy. (Choices B and E) Gastroesophageal reflux disease (GERD) and upper airway cough syndrome (UACS) (postnasal drip) are 2 of the most common causes of chronic cough. However, patients with GERD typically have accompanying symptoms of reflux and heartburn following meals. In patients with UACS, accompanying rhinorrhea is expected, and oropharyngeal cobblestoning is often present on examination. (Choice C) Laryngeal nodules can result from chronic irritation of the vocal cords (eg, from smoking). Patients typically have hoarseness rather than cough and chest tightness. (Choice D) Tracheomalacia describes weakness of the walls of the trachea leading to expiratory airway collapse. Patients often have coughing and shortness of breath as well as stridor on physical examination. Chest tightness is not typical. Educational objective: Cough-variant asthma presents with a chronic nonproductive cough that is typically worse at night and triggered by exercise, forced expiration, and allergen exposure. The diagnosis can be challenging as these patients typically lack classic asthma symptoms (eg, wheezing, shortness of breath) and physical examination is often largely unremarkable, even during periods of active symptoms. References: Causes of chronic cough in non-smoking patients. (http://www.ncbi.nlm.nih.gov/pubmed/26285610)

A 28-Year-Old Man Comes to the Clinic Due to a Nonproductive