A 34-year-old man comes to the office due to shortness of breath. He reports an episodic cough and chest tightness for the past 4 months. The patient was recently on a 2-week vacation in Arizona and reports that he had no symptoms during the trip but that they restarted when he returned home. He has no prior medical conditions and takes no medications. The patient smoked marijuana in his early 20s for several years but does not use tobacco or alcohol. He started working at a chemical manufacturing factory 7 months ago and has had no sick contacts. Temperature is 36.7 C (98 F), blood pressure is 120/80 mm Hg, pulse is 76/min, and respirations are 18/min. On physical examination, expiration is mildly prolonged and there are scattered wheezes. Office spirometry shows an FEV1/FVC of 82%, and chest radiography reveals no abnormalities. Which of the following features is most likely involved in the pathogenesis of this patient's condition?

Question

A 34-year-old man comes to the office due to shortness of breath.  He reports an episodic cough and chest tightness for the past 4 months.  The patient was recently on a 2-week vacation in Arizona and reports that he had no symptoms during the trip but that they restarted when he returned home.  He has no prior medical conditions and takes no medications.  The patient smoked marijuana in his early 20s for several years but does not use tobacco or alcohol.  He started working at a chemical manufacturing factory 7 months ago and has had no sick contacts.  Temperature is 36.7 C (98 F), blood pressure is 120/80 mm Hg, pulse is 76/min, and respirations are 18/min.  On physical examination, expiration is mildly prolonged and there are scattered wheezes.  Office spirometry shows an FEV1/FVC of 82%, and chest radiography reveals no abnormalities.  Which of the following features is most likely involved in the pathogenesis of this patient's condition?

Quizplus · Accepted Answer

This patient with dyspnea, cough, and intermittent chest tightness likely has asthma. The correlation of symptom onset after starting a new job and relief while traveling is suggestive of occupational asthma (OA), which accounts for up to 25% of adult-onset asthma. OA is characterized by airway inflammation, bronchial hyperreactivity, and a variable airflow obstruction triggered by a workplace exposure. Like other forms of asthma, patients may have normal chest imaging and pulmonary function tests between exacerbations. Inciting factors in OA can be categorized as immunologic or nonimmunologic: Immunologic: Similar to atopic asthma, exposure to workplace aero-allergens induces a Th2-mediated reaction, which stimulates IgE formation and eosinophilic activation. There is often a latent period before symptoms develop during which the patient is sensitized to an allergen. Common causes include cereals, latex, and chemicals (eg, formaldehyde, amines, dyes). Nonimmunologic: Exposure to aero-irritants induces denudation of the airway mucosa, resulting in persistent airway inflammation, loss of epithelial relaxation factors, and mast cell degranulation. This typically occurs after large accidental exposures (eg, chemical spill), and symptom onset is sudden and severe. Common causes include chlorine and ammonia. (Choice B) Coccidioidomycosis is endemic to the southwestern United States. In addition to cough and chest pain, patients commonly have fever, arthralgia, and skin manifestations, and imaging often demonstrates hilar adenopathy. This patient developed symptoms prior to his travel to Arizona. (Choice C) Alpha-1 antitrypsin deficiency is an inherited disorder that causes panacinar emphysema. Patients present with dyspnea, cough, and wheezing; however, imaging typically reveals basilar bullous changes and spirometry shows an obstructive pattern. (Choice D) BMPR2 gene mutations cause idiopathic pulmonary hypertension; symptoms include progressive dyspnea and fatigue. However, cough, wheezing, and the resolution of symptoms while traveling is unexpected. In addition, imaging often reveals enlarged pulmonary arteries. (Choice E) Eosinophilic granulomatosis with polyangiitis (Churg-Strauss) is a vasculitis of small- or medium-sized arteries characterized by asthma and rhinitis. However, imaging typically demonstrates patchy infiltrates, and symptoms would not be expected to resolve while traveling. Educational objective: Occupational asthma is characterized by airway inflammation, bronchial hyperreactivity, and a variable airflow obstruction triggered by workplace exposure. Exposure can be immunologic (atopic), due to exposure to a workplace aeroallergen causing a Th2-mediated IgE formation, or nonimmunologic, due to exposure to workplace irritants that lead to denudation of the bronchial mucosa.

A 34-Year-Old Man Comes to the Office Due to Shortness