Primary subacute haematogenous osteomyelitis in children.

Between 1990 and 1998 we saw 21 children with primary subacute haematogenous osteomyelitis. Pain, swelling and a limp had been present for two to 12 weeks with little functional impairment. Laboratory tests were non-contributory. The lesions were classified radiologically into metaphyseal, diaphyseal, epiphyseal and vertebral. There were 24 sites involved, with most (20) being in the tibia; 17 lesions were in the diaphysis, five in the metaphysis and two in the epiphysis. The diagnosis was confirmed histologically in all cases. Staphylococcus aureus was cultured in six patients. Healing occurred in all patients after treatment with antibiotics for six weeks and radiological improvement was seen after three to six months. Subacute osteomyelitis develops as a result of increased host resistance and decreased bacterial virulence. The radiological features can mimic various benign or malignant bone tumours and non-pyogenic infections. Histological confirmation is necessary to avoid a delay in diagnosis.