Pelvic osteomyelitis: Three unusual cases with predominantly abdominal symptoms.

Abstract

Paediatric osteomyelitis involves the pelvis in less than 10% of cases.1 Children usually present with a fever and limp or inability to weight bear.2 Isolated abdominal symptoms are uncommon, accounting for 5% of pelvic osteomyelitis presentations.3 We report three cases of paediatric osteomyelitis seen within a 6-month period with predominantly abdominal symptoms, presenting a diagnostic challenge. A 15-year-old boy presented with right iliac fossa pain and tenderness and mild fever. White cell count (WCC) was 21 × 109/L and C-reactive protein (CRP) 22 mg/L. Following observation overnight and inconclusive ultrasound scan (USS), open appendicectomy was performed, revealing a mildly inflamed appendix. He was discharged on post-operative day 1, re-presenting the following day with severe leg pain and difficulty weight bearing. Magnetic resonance imaging (MRI) was consistent with osteomyelitis of the right inferior pubic ramus. An 11-year-old girl presented with 3-day history of fever, vomiting and left iliac fossa and suprapubic pain and tenderness. WCC was 7.6 × 109/L and CRP 213 mg/L. Abdominal and pelvic X-rays were unremarkable. USS showed bladder wall thickening and inflammatory changes in the pre-vesical space. MRI was consistent with osteomyelitis of the left inferior pubic ramus (Fig. 1). A 2-year-old boy presented with 3-day history of constipation and irritability. An enema was administered with initial symptomatic improvement. A fever and limp developed in the emergency department. Lower limb examination was normal. X-ray and USS were unremarkable. WCC was 10.1 × 109/L and CRP 100 mg/L. Whole body bone scan was consistent with right posterior iliac osteomyelitis. All three children recovered fully with antibiotic treatment. Paediatric pelvic osteomyelitis is a rare entity and an initial presentation without limb symptoms is exceedingly uncommon.1-3 As abdominal symptoms may precede limb symptoms in certain cases, the diagnosis should be considered when abdominal or other pelvic pathology is not apparent. MRI is the investigation of choice for pelvic osteomyelitis.2