Osteomyelitis and pyogenic sacroiliitis: A difficult diagnosis.

Pyogenic sacroiliitis is an uncommon infection often diagnosed late because of poor localization of symptoms and inadequate physical examination. We describe a 12-year-old girl whose osteomyelitis and pyogenic sacroiliitis was initially misdiagnosed and discuss examination, investigation and management of the condition. This case highlights the importance of thorough physical examination and the consideration of septic arthritis in an unusual joint.