Pyomyositis in Babies Presenting with Painful Hip: Clinical and Radiographic Course of Two Cases

Abstract

Two cases of pyomyositis in babies, one in the ilio-psoas muscle, the other in the quadriceps, are reported. The presenting sign was a painful hip in both, suggesting osteomyelitis of the proximal femur or arthritis. Pyomyositis is unusual in western countries and in healthy, well-nourished children, but these cases suggest considering this pathology in the differential diagnosis of a painful hip in babies.

In the first case an upper respiratory tract infection was followed by haematogenous spread to the ilio-psoas muscle; in the second an injection of vaccine in the quadriceps played a determinant role. The latter case was complicated by secondary osteomyelitis; a metaphyseal radiolucent band just below the growth plate appeared in the early stage together with metaphyseal osteopenia and was interpreted as a consequence of altered blood flow in the metaphysis, not specific osteomyelitis, but indicative of some disturbance of the growth plate-metaphyseal complex.