Tropical pyomyositis of the hip short external rotators associated with elevated intra compartmental pressure.

Two boys with the clinical and radiographic picture of acute tropical pyomyositis of the short external rotators of the hip were treated surgically followed by parenteral antibiotics (Figure 1). Intraoperatively, no pus was found. Histopathology specimens from 1 patient demonstrated small foci of degenerative changes and necrosis without evidence of infection (Figure 2). Prior to decompressing the muscle in the second patient, intramuscular pressure was measured and found to be significantly elevated. Surgical decompression was performed and both patients fully recovered after a course of intravenous antibiotics. Tropical pyomyositis' clinical presentation is often insidious with a variable course accounting for its frequent missed or late diagnosis. Often the illness progresses through three stages - invasive, suppurative, and late. Patients progress from a diffuse muscle inflammation to abscess formation and sepsis. Staphylococcus aureus is responsible for the infection in >75% of the cases. The quadriceps, iliopsoas, and gluteal muscles are most commonly affected. Multiple reports addressed the optimal treatment of tropical pyomyositis. Traditionally, surgical treatment was advocated. However, there are reports of successful nonsurgical or minimally invasive treatment. Based on our experience, it is suggested that the sequence of events in the development of tropical pyomyositis is an initial insult such as vigorous exercise, leading to elevated compartment pressure, resulting in a compartment syndrome. If simultaneous bactermia occurs, the vulnerable muscle is seeded with the infectious organism and abscess formation follows. That may explain other authors' findings that early aspiration, combined with antibiotic treatment, may be sufficient to decompress the muscle, prevent abscess formation and result in full recovery.