[Primary pyogenic abscess of the psoas muscle. Apropos of 5 cases].

The authors discuss the diagnostic and therapeutic aspects of primary pyogenic abscess of the psoas muscle based on a series of 5 cases. Five patients between the ages of 15 and 64 years (mean: 38.2 years) were admitted to the urology department between January 1994 and December 1996 with fever, abdominal pain and low back pain, and psoitis in 1 case. The mean delay to consultation was 42 days. Clinical examination revealed a painful mass in the lumbar region and flank in 5 cases. Leukocytosis was detected in 5 patients. Radiological examination demonstrated loss of the lateral border of the psoas in 4 cases. Ultrasonography showed an enlarged psoas muscle in every case with a hypoechoic mass in 2 cases and a heterogeneous mass in the other 3 cases. Computed tomography, performed in 2 patients, confirmed the ultrasound findings in 1 case and excluded the diagnosis of type IV hydatid cyst of the psoas muscle in the other patient. The abscess was evacuated by percutaneous drain in 1 patient requiring a second percutaneous drainage for reconstitution of the abscess. Surgical drainage was performed immediately in 3 patients and after failure of antibiotic treatment in 1 patient. The hospital stay did not exceed 7 days after surgical drainage, but was 25 days after the first percutaneous drainage and 20 days after the second percutaneous drainage. The authors emphasize the multiple advantages and efficacy of surgical drainage of psoas abscess.