Extensive pyogenic myositis of the hip in an immuno-competent patient

Pyogenic myositis is a primary subacute deep bacterial infection of the skeletal muscle. It is a rare condition that is usually regarded as a tropical disease being common in parts of Africa and the South Pacific. It has been reported in patients of all ages but is predominantly a condition afflicting children and young adults. The development of pyogenic myositis is thought to arise from a transient bacteraemia associated with risk factors such as recent trauma and immunocompromise. Pyogenic myositis is associated with serious complications if not treated promptly. These include septic arthritis, lung and brain abscess formation, pericarditis, endocarditis, septicaemia and death. Long-term sequelae such as osteomyelitis, muscle-scarring and residual muscle weakness can be prevented by early diagnosis and treatment of this condition. Three stages in the pathogenesis of pyogenic myositis have been proposed by Bickels et al. In the first stage, patients present with a low grade fever, general malaise and muscle ache. As the inflammatory process is sealed within enveloping muscle fascia, the presence of local signs of inflammation may be absent, with only systemic signs of infection/inflammation present. In stage 2, muscle abscess formation is seen, associated with local and systemic signs of infection/inflammation. If pyogenic myositis is subsequently not treated, patients may progress to stage 3, where they develop septicaemia and require urgent intervention. We report a case of spontaneous extensive pyogenic myositis of the hip musculature in an immuno-competent patient with no identifiable risk or triggering factors.