[Tropical pyomyositis simulating septic arthritis in AIDS patients. Two cases]

Tropical pyomyositis (TP) is an acute bacterial infection of skeletal muscles characterized by rapid formation of abscesses. Since the beginning of the AIDS epidemic, interest in TP has increased because of its rising incidence in association with HIV infection and of the problems that it poses for differential diagnosis. Occurrence of TP is a criterion for classification of HIV infected patients in WHO disease stage III. The purpose of this report is to describe two HIV-infected patients who presented TP simulating septic arthritis of the hip and knee respectively. Medical imaging was particularly useful in establishing accurate topographic diagnosis and needle drainage in decreasing the duration of hospitalization and avoiding the need for surgical debridement. Needle puncture must be guided by ultrasound or scan imaging.