Abstract Introduction E-cigarette use has risen dramatically in the past decade, accompanied by recognition of e-cigarette or vaping-use associated lung injury (EVALI). Although increasingly reported, the pathophysiology of EVALI remains poorly defined, and its clinical presentation and diagnostic evaluation are often nonspecific. Clinicians should maintain a high index of suspicion given its varied manifestations. We describe a young patient with EVALI complicated by histopathologic evidence of secondary pulmonary alveolar proteinosis (PAP), progressing to severe hypoxemic respiratory failure that ultimately required bilateral lung transplantation. Case Presentation A 28-year-old man with a nine-year history of vaping nicotine and THC-containing hash oil presented with chronic hypoxemic respiratory failure requiring BiPAP. One year earlier, he developed digital clubbing, followed by progressive cough and exertional dyspnea. Initial chest CT showed diffuse centrilobular ground-glass opacities without septal thickening, thought to represent hypersensitivity pneumonitis. Despite vaping cessation several months prior to presentation, his symptoms progressed rapidly, and he required high-flow supplemental oxygen (Fi02 80% at 50 L/min) within weeks of admission. Bronchoscopy with bronchoalveolar lavage and biopsy demonstrated focal organizing pneumonia, pigmented foamy macrophages, and eosinophilic acellular debris within alveoli, consistent with pulmonary alveolar proteinosis (PAP). Cultures and cytology were negative for infection or malignancy. Autoimmune serologies were unrevealing, and no alternative exposures were identified. Due to worsening hypoxemic respiratory failure and lack of response to vaping cessation, steroids, and nebulized sargramostim (recombinant human granulocyte-macrophage colony-stimulating factor), he underwent bilateral lung transplantation. Whole lung lavage was considered but not pursued due to concern for further deterioration. Explant pathology showed interstitial fibrosis with a nonspecific interstitial pneumonia pattern and extensive PAP-like reaction with cholesterol clefts and small airway injury. Discussion EVALI encompasses a broad spectrum of radiographic and histopathologic findings, but secondary pulmonary alveolar proteinosis (PAP) is rarely reported. Diagnostic criteria include e-cigarette use within 90 days and pulmonary infiltrates or ground-glass opacities, with exclusion of malignant, autoimmune, and infectious causes. Although most often associated with ground-glass opacities and organizing pneumonia with diffuse alveolar damage, the pathology of EVALI is variable and poorly understood, further complicated by heterogeneity in vaping exposures. This case highlights PAP as a potential manifestation of EVALI, raising the possibility that impaired alveolar macrophage function and surfactant clearance contribute to hypoxemia in severe disease. Clinicians should maintain a high index of suspicion for EVALI and be aware of its diverse histopathologic spectrum. Continued research is needed to clarify underlying mechanisms and guide management. This abstract is funded by: None
Wexler et al. (Fri,) studied this question.