A FRESH LOOK AT OLD GRANULOMAS: 16 YEARS OF HOT TUB LUNG

Abstract

SESSION TITLE: Medical Student/Resident Occupational and Environmental Lung Disease SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Hot Tub Lung is a hypersensitivity pneumonitis provoked by contaminated water exposure. Here we present a case of a man with rapid resolution of 16 years of clinical symptoms and functional disability after removal of his hot tub. CASE PRESENTATION: A 56-year-old man presented for a second opinion for progressive exertional limitation and interstitial lung disease. A surgical lung biopsy performed 16 years previously showed interstitial noncaseating granulomatous inflammation with eosinophils and bronchiolitis obliterans with organizing pneumonia - interpreted as suggestive of hypersensitivity pneumonitis or sarcoidosis. He was told he likely had sarcoidosis and was intermittently treated with steroids. He initially required intermittent oxygen therapy and after 5 years progressed to continuous use at 3 liters per minute. Further history obtained when we saw him was pertinent in that he enjoyed regular use of his hot tub at home. A chest CT scan showed diffuse ground glass opacities without evidence of fibrosis. Sputum cultures were positive for Mycobacterium avium complex (MAC), Mycobacterium fortuitum, Mycobacterium mageritense and Nocardia farcinica. Pathology re-review of his lung biopsy suggested Hot Tub Lung as a potential etiology given well-formed granulomas in a peribronchiolar distribution. On subsequent evaluation 3 months after removing his hot tub, a repeat CT scan showed his bilateral ground glass changes had resolved, sputum cultures were negative and he had no need for supplemental oxygen. His FEV1 in 3 months increased from 1.32 liters (33% predicted) to 2.49 liters (60% predicted) - an 89% improvement. On further discussion 7 months after hot tub removal, our patient felt “let out of prison,” was no longer disabled and was preparing to return to work as an electrician. DISCUSSION: Hot Tub Lung is diagnosed by characteristic findings, including persistent respiratory symptoms like cough and dyspnea, diffuse lung infiltrates on imaging, hot tub exposure and isolation of MAC species on respiratory culture, lung biopsy or hot tub water sample. It is characterized as a hypersensitivity pneumonitis rather than an infectious process as avoidance of antigen exposure is often sufficient to resolve symptoms. To our knowledge, this patient’s long duration of exposure is unique in the literature for Hot Tub Lung. Chronic hypersensitivity pneumonitis is often associated with fibrosis which was not seen here. This suggests that Hot Tub Lung can “smolder” over many years without irreversible change taking place. CONCLUSIONS: Hot Tub Lung should be considered when evaluating a granulomatous lung disorder. This case also highlights the importance of fresh clinicopathologic re-evaluation when diagnoses are in doubt. Reference #1: Mukhopadhyay S, Gal AA. Granulomatous Lung Disease: An Approach to the Differential Diagnosis. Arch Pathol Lab Med. 2010;134:667-690. Reference #2: Hanak V, Kalra S, Aksamit TR, Harman TE, Tazelaar HD, Ryu JH. Hot tub lung: Presenting features and clinical course of 21 patients. Respir Med. 2006;100:610-615. Reference #3: Vourlekis JS, Schwarz MI, Cherniack RM, Curran-Everett D, Cool CD, Tuder RM, et al. The Effect of Pulmonary Fibrosis on Survival in Patients with Hypersensitivity Pneumonitis. Am J Med. 2004;16:662-668. DISCLOSURES: No relevant relationships by Derek Hupp, source=Web Response No relevant relationships by Chris Jensen, source=Web Response No relevant relationships by Jeff Wilson, source=Web Response