PRIMARY PSOAS ABSCESS - A REVIEW OF 16 CASES

Objective. Most psoas abscesses are secondary. The objective of this s tudy was to report on the clinical features, diagnosis and treatment o f primary psoas abscess. Methods. We retrospectively studied 16 cases seen over a ten-year period (1987-1997) and compared our findings to p ublished data. Results. There were 14 men and two women, with a mean a ge of 6 years (range, 17-57 years), The right side was affected in nin e cases, the left side in six, and both sides in one. Fever, pain and psoas spasm were the presenting symptoms. Laboratory tests for inflamm ation were positive; four patients had a high neutrophil count. Ultras onography demonstrated a fluid collection in the psoas in 13 patients. A computed tomography scan was done in 14 patients and showed either a fluid collection (n = 11) or a presuppurative abscess (n = 3). Magne tic resonance imaging was not used. The organism was recovered in nine patients and was a Staphylococcus aureus in seven, an Escherichia col i in one and a Pseudomonas aeruginosa in one. The Brucella agglutinati on test was strongly positive in two patients. Findings were negative from investigations done to look for a cause (discitis, urinary tract infection, Crohn's disease, ulcerative colitis, malignancy or infectio n in the vicinity of the psoas muscle). All patients received antimicr obial therapy. Drainage was percutaneous in six patients and surgical in ten, The outcome was favorable in every case.