Osteomyelitis of the sacrum as the initial manifestation of Crohn's disease.

A 17-year-old boy had low back pain for four months prior to the development of sacral osteomyelitis, which led to the initial diagnosis of Crohn's disease. Musculoskeletal problems occur in about one-third of the patients with Crohn's disease. Only a few patients with osteomyelitis complicating Crohn's disease have been reported. This case is rare because he had had no gastrointestinal symptoms. This patient illustrates the point that musculoskeletal signs and symptoms, including osteomyelitis, may prove to be a manifestation of gastrointestinal tract disease.