SELECTED ARTICLES FROM THE RECENT LITERATURE 2005

11/28/05

Hot tub lung syndrome- clinical and pathologic characteristics

Summary
Background - "Hot tub lung" (HTL) is an emerging disorder associated with exposure to certain microorganisms contaminating hot tub water, particularly Mycobacterium avium complex (Mac).

Findings - Hanak et al of the Mayo Clinic in Rochester, MN retrospectively reviewed 21 cases diagnosed with HTL over a 7 year period. All patients had repeated, ongoing exposures to hot tubs. The most common presenting symptoms were cough and dyspnea with hypo oxemia in 48% of the patients. High resolution chest CT exams showed diffuse centrilobular nodules and/or ground glass opacities. Mac was isolated from hot tub water, respiratory secretions and/or lung tissue in all cases. Lung biopsies showed bronchiolocentric granulomatous inflammation. With avoidance of hot tubs, improvement occurred in all cases. Corticosterid therapy was also given in 62% of cases but anti-mycobacterial therapy was used in only one patient. The authors postulated that this pulmonary disorder was a form of hypersensitivity pneumonitis to Mac that should improve with avoidance of hot tubs. Anti-mycobacterial therapy was not necessary.

Reference
Respir Med 2005; Sept 26 E pub

Editor's Comments
I have reviewed this interest case series description because asthma, along with sarcoid and bronchitis, were diagnoses initially considered in these cases before the association with hot tub exposure was recognized. It would have been of considerable interest if the authors described results of any attempt to detect immuno responses to Mac in these patients (vs controls) and whether Mac antigens were present in the lung granulomas.

 

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