Pyogenic Infection of the Sacroiliac Joint Complicated by Iliacus Abscess in a Paediatric Patient

Pyogenic sacroiliitis is a rare disease entity, comprising only 1% to 2% of cases of osteomyelitis and septic arthritis. Clinical symptoms and signs are usually non-specific and may result in delayed diagnosis. This report is of a 15-year-old girl with pyogenic sacroiliitis and iliacus abscess without any predisposing factors. Various imaging modalities, including computed tomography and magnetic resonance imaging, were performed. The diagnosis was confirmed by magnetic resonance imaging and the patient was treated successfully. This patient illustrates the importance of high clinical alertness and the use of magnetic resonance imaging for confirming the diagnosis.