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 who was transplanted for end-stage renal failure secondary to cystic kidney disease. Symptoms of severe obstructive airway disease developed 2 months after transplantation under immunosuppression with prednisone, azathioprine, and tacrolimus. The patient did not develop signs of infection; progressive shortness of breath remained the only symptom for several weeks. After extensive diagnostic evaluation, bronchoalveolar lavage revealed Moraxella catarrhalis as the single infectious agent. After 3 weeks of appropriate antibiotic therapy, symptoms of obstructive airway disease were completely relieved. This atypical presentation of Moraxella infection in an immunocompromised host represents a rare complication of renal transplantation, especially in young patients. Special aspects such as frequency, diagnosis, differential diagnosis, and management of this rare complication of renal transplantation in a pediatric patient are discussed.