Obstructive airway disease caused by Moraxella catarrhalis after renal transplantation

We report a case of severe acute obstructive airway disease 2 months after renal transplantation in a 16-year-old patient with Biedl-Bardet syndrome w ho was transplanted for end-stage renal failure secondary to cystic kidney disease. Symptoms of severe obstructive airway disease developed 2 months a fter transplantation under immunosuppression with prednisone, azathioprine, and tacrolimus. The patient did not develop signs of infection; progressiv e shortness of breath remained the only symptom for several weeks. After ex tensive diagnostic evaluation bronchoalveolar lavage revealed Moraxella cat arrhalis as the single infectious agent. After 3 weeks of appropriate antib iotic therapy, symptoms of obstructive airway disease were completely relie ved. This atypical presentation of Moraxella infection in an immunocompromi sed host represents a rare complication of renal transplantation, especiall y in young patients. Special aspects such as frequency, diagnosis, differen tial diagnosis, and management of this rare complication of renal transplan tation in a pediatric patient are discussed.