INTRODUCTION:Mycobacterium chelonae is a relatively rare Mycobacterium other then tuberculosis [MOTT]. We report the first case of Mycobacterium chelonae in a non-immunocompromised female diagnosed with hot tub lung.
CASE PRESENTATION:A 36-year-old, non smoking Caucasian female was admitted to the hospital with a complaint of dyspnea, nonproductive cough, and decreased exercise tolerance. She denied any recent travel. She did have a pet hamster. She denied any occupational or non occupational exposures to anyone ill. Until this illness, the patient was active, exercised regularly and enjoyed relaxing in her home spa. At the time of admission, the patient had a temperature of 99.2 degrees F, respirations of 22, HR of 89, blood pressure of 110/72, saturating 95% on room air. On physical exam the patient was a well-developed, well-nourished female, with bilateral expiratory wheezes. The patient’s Chest X-ray was normal. However, High - Resolution Chest CT scan was grossly abnormal, showing numerous areas of air trapping bilaterally with centrolobular nodular opacities and ground-glass in a patchy distribution. A hypersensitivity pneumonitis panel was normal as were antigens to Cryptococcus and Histoplasmosis. Antibodies to Coccidiomycosis, Coxiella burnetti, and Chlamydia were negative. CMV and EBV PCR, Tularemia agglutinin and Aspergillus CF were also negative. HIV and PPD tests were non-reactive. Bronchoscopy with BAL and transbronchial biopsies was performed and suggested lipoid pneumonia or hypersensitivity pneumonitis. The biopsy also showed a few multinucleated histiocytes, a feature seen in HP. Stains for PCP and malignant cells were negative. Video assisted thoracic surgical wedge resections from the right middle and lower lobes were performed. The pathology demonstrated findings consistent with extrinsic allergic alveolitis or hypersensitivity pneumonitis, which included non-necrotizing epithelioid granulomas. In addition, Mycobacterium chelonae grew from piece of tissue cultured. The patient was treated with avoidance of the hot tub. In addition the patient was treated with a 3 month course of antibiotics and steroids. The patient improved dramatically and is presently asymptomatic.
DISCUSSIONS:Hot Tub Lung was first described by Kahana and colleagues in a case report in 1997. The description of this disorder has been limited to several case reports published since that time. Diagnostic criteria for hot tub lung has been outlined in past papers and include persistence of respiratory symptoms, diffuse lung infiltrates on chest radiography or computed tomography, Mycobacterium isolated from respiratory secretions, hot tub water sample or lung tissue biopsy, no other identifiable cause for the illness, and most importantly exposure to hot tub prior to onset of illness. This case meets all the criteria above; however is unique in that Mycobacterium chelonae grew from the lung biopsy. Furthermore, the findings on lung tissue biopsy in a past case series demonstrates non-necrotizing granulomas in eighteen of twenty-one cases of hot tub lung, also a finding found on our biopsy. Treatment in this case was successful and analogous to other reports in the literature of hot tub lung.
CONCLUSION:A literature review revealed only twenty-one prior case reports of hot tub lung. This is the first case in which Mycobacterium chelonae has been the pathogen involved. There is a continued debate as to whether hot tub lung represents an infectious or hypersensitivity phenomenon related to MAC organisms. This case provides further evidence that Hot Tub lung could have an infectious component and is not entirely limited to Mycobacterium avium complex (MAC).
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