Primary pyomyositis in children

Pyomyositis (PM) is defined as a primary pyogenic infection of the striated skeletal muscle; although it has many dystrophic musculoskeletal complications, it is always misdiagnosed by many orthopedic surgeons.

PM is rare in temperate climates and usually considered to be a tropical disease, until recent times, after globalization, it is possible to occur in the subtropical climate as in our country.

In the present series, the results of 15 children patients with primary pyomyositis have been reviewed. In five out of them, conservative treatment protocol alone which has been by intravenous and oral antibiotics therapy was effective. The remaining ten patients with confirmed abscess formation needed invasive procedures which have been percutaneous US-guided drainage in two patients and an open surgical drainage in the remaining 8 patients.

Conservative treatment was successful in five cases with marked improvement within 3 days, but in the other ten patients who needed surgical treatment, all were effectively treated except three out of them who were complicated as follows; elbow stiffness in one case, hip joint septic arthritis with epiphysitis in the second case and osteomyelitis of the lower femoral end with knee joint septic arthritis in last one.

Both clinical picture and laboratory investigation of PM are not specific and resembled many other differential diagnoses so the proper imaging study is of valuable importance needs to be accurately identified and treated to avoid its delayed complications.

In children complaining of joint pain or muscle aches and septic-appearing, pyomyositis should be considered in the differential diagnosis. MRI is the most valuable tool for diagnosis of PM. Early diagnosis, the use of appropriate antibiotic therapy and complete drainage of the purulent material are important factors for successful treatment that leads to complete resolution of PM.

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