[Pyomyositis in children: not only a tropical disease]

Pyomyositis is an acute bacterial infection of skeletal striated muscle typical of tropical countries but infrequent in our environment. The present review aims to describe the clinical characteristics, epidemiology, etiology, diagnosis and outcome of patients with pyomyositis in our hospital.

The medical records of patients diagnosed with pyomyositis in our hospital from 2002 to 2005 were reviewed. Epidemiological, clinical, and microbiological data as well as the diagnostic tests and treatment strategies used were gathered and a descriptive analysis was performed.

There were seven patients (five boys and two girls). The mean age of the patients was 8.6 years. Five patients (70%) presented during the 6 warmer months. There were four secondary cases (one HIV infection, three musculoskeletal injuries). The most frequent sites were the psoas-iliac region and thigh. The main symptoms at presentation were pain and fever. The most common diagnostic imaging modality was ultrasound examination, although magnetic resonance imaging had the highest diagnostic yield (sensitivity of 100% versus 33% for ultrasound). The most prevalent microorganism in our series was Staphylococcus aureus (found in three out of seven patients). Only two abscesses were surgically drained and the remainder were treated with antibiotics alone, first intravenously (mean of 17 days) and then orally (mean of 26 days). None of our patients developed sequelae.

Pyomyositis should be included in the differential diagnosis in children with fever, pain and/or functional impotence, even though this entity is infrequent in our environment. The most sensitive diagnostic test is magnetic resonance imaging. With early diagnosis and correct treatment, outcome is good.