Pyomyositis in a 5-year-old child.

We present a case of pyomyositis in an otherwise healthy 5-year-old child that underscores the potential for serious, life-threatening complications. Pyomyositis of the gluteal, psoas, and iliacus muscles was associated with osteomyelitis, septic arthritis, a large inferior vena cava thrombus, septic pulmonary emboli, and eventual pneumonia. Primary pyomyositis is a purulent infection of striated muscle thought to be caused by seeding from a transient bacteremia. The focal infection typically forms an abscess that generally responds to intravenous antibiotics and occasionally requires adjunctive computed tomography-guided aspiration and drainage. This localized infectious process rarely produces further sequelae unless treatment is delayed. Pyomyositis is rare in healthy individuals and requires a high clinical suspicion in patients who present with fever, leukocytosis, and localized pain.