ABSTRACT
Introduction: Hypersensitivity pneumonitis is an interstitial lung disease caused by lymphocytic response to inhalant exposures such as molds or avian excreta. Given its complexity and variation in presentation, the diagnosis of hypersensitivity pneumonitis requires obtaining a detailed exposure history and thorough workup. Case Description: A 17-year-old previously healthy female without asthma history developed cough, fever, and shortness of breath. A week later, she was intubated for acute respiratory failure. Her initial imaging revealed pneumomediastinum and pneumopericardium with ground glass opacities. The etiology of her respiratory failure remained unclear. Infectious workup, including multiple COVID tests, was negative. Given that she cares for horses, a hypersensitivity pneumonitis panel was done and revealed elevated aspergillus fumigatus IgG level >200 mcg/mL and total IgE of 571 kU/L. BAL showed elevated neutrophil count and lung biopsy was not obtained. She was extubated after a week and subsequently revealed that she vapes marijuana. This introduced e-cigarette and vaping associated lung injury (EVALI) as another etiology for her presentation. She ultimately completed an extended course of steroids and was discharged on supplemental oxygen. Discussion: Our patient presented with acute respiratory failure and negative infectious workup. Initial social history revealed frequent exposure to horse barns, leading to a diagnosis of hypersensitivity pneumonitis. However, it was subsequently revealed that she vaped, which introduced EVALI as another possibility. While her final diagnosis remains nebulous, this case highlights the importance of maintaining a broad differential during assessment of acute respiratory failure and the critical role that astute history taking plays in the diagnostic process. [Formula presented]