Objective: To analyze the characteristics of abscesses of the psoas muscle and assess the differences between pyogenic and tuberculous abscesses.
Methods: Retrospective descriptive study of all patients with psoas abscess in our hospital over the period 1994 to 2004.
Results: Fourteen patients were studied (10 males), with a mean age of 42 years. Half of them had had an underlying disease. The most frequent clinical manifestations were abdominal pain (64%), fever (57%), and back pain (43%). All the abscesses were secondary. In 7 patients the origin was gastrointestinal, in 6 osteoarticular, and 1 was related with infection of an aortobifemoral bypass. Computed tomography was the diagnostic imaging method in all patients. Culture of drainage specimens was positive in 92% of patients undergoing this procedure. Causal microorganisms included Mycobacterium tuberculosis (5), Streptococcus intermedius (4), Staphylococcus aureus (3), Escherichia coli (3) and Bacteroides fragilis (2). Tuberculous abscesses originated in spondylitis and the clinical presentation was longer prior to diagnosis. Drainage was performed in 12 patients (8 percutaneous and 4 surgical). Mean duration of antimicrobial therapy was 4 weeks. The infection resolved in all patients.
Conclusions: Psoas abscess commonly had a gastrointestinal and osteoarticular origin. We underscore the high percentage of tuberculous etiology, which had a more insidious clinical and analytical presentation and was usually secondary to spondylitis. Prolonged antimicrobial treatment associated with drainage was effective therapy.