Mycobacterium intracellulare pulmonary infection in an immunosuppressed child with Crohnʼs Disease

Abstract

A 14-year-old boy was diagnosed with Crohn's disease two years ago and has had several exacerbations which were treated with azathioprine and mesalazine. Despite he didn't show any respiratory symptoms or weight loss, plain radiographs and computed tomography scans of his chest revealed small centrilobular nodules and bronchiectasis involving the right middle and lower lobe. Bronchoscopic examination of the airways did not reveal any endobronchial lesions. Empirical anti-tuberculosis medication was started but immediately discontinued inevitably because the patient complained of severe nausea and vomiting. Soon after, sputum APB culture in liquid media identified Mycobacterium intracellulare infection. The sputum culture samples had a positive result by rpoB-PCR and negative for IS6110-PCR, which were considered to be non-Mycobacterium tuberculosis. All other cultures including AFB were negative in his bronchial washing. Six weeks after ceasing his current medication, azathioprine, chest high resolution CT demonstrated markedly decreased and minimal residual bronchiectatic lesions in the previous site. At that time, the patient's Crohn's disease was aggravated with concurrent trans-abdominal fistula and he underwent incision, drainage, and fistulectomy. He was injected with monoclonal antibody of TNF-alpha with close monitoring of his chest radiograph. After 6 months, there was almost complete resolution of his chest radiograph without treatment of Mycobacterium intracellulae. And also clinical remission of Crohn's disease was measured by a decrease in the Pediatric Crohn's Disease Activity Index. We experienced a case of Mycobacterium intracellulare pulmonary infection in an immunosuppressed child with Crohn's disease who was recovered without anti-tuberculosis medication.