Primary pyogenic psoas abscess in children.

Primary pyogenic psoas abscess, although quite a common condition, particularly in the tropics, is often overlooked as a clinical entity, probably because a psoas abscess has been traditionally associated with tuberculous spondylitis. The abscess is easily diagnosed by ultrasonography (US). Treatment by open drainage and antibiotics effective against Staphylococcus aureus results in complete reversal of symptoms and signs. In our series of 55 cases in the pediatric age group (0-12 years), pain and flexion at the hip were the most frequent clinical features at presentation. US was diagnostic in all cases in which it was performed. All except 1 patient showed complete resolution with extraperitoneal drainage, antibiotics, and skin traction. Although 4% of the cases were associated with suppurative external-iliac lymphadenitis, the remaining ones arose de novo in the psoas sheath, suggesting a primary pyomyositis of the psoas muscle.