Iliopsoas Abscesses: Whose Problem is it? Insights Gained by an Institutional 100-Patient Consecutive Case Series.

Abstract

Iliopsoas abscess (IPA) is a rare but serious condition caused by hematogenous or contiguous spread of infection. Management typically involves broad-spectrum antibiotics, with percutaneous or surgical drainage for larger abscesses. We retrospectively reviewed 113 IPA cases at the Swedish Neuroscience Institute (2015-2024), analyzing demographics, clinical features, imaging, treatment strategies, hospital course, and outcomes. Among 100 patients included, 86 presented with back or flank pain, 45 with abdominal pain, and 35 with lower extremity discomfort. The most common pathogens were Staphylococcus aureus (38%) and Escherichia coli (31%). Mean patient age was 56 years (range: 32-71); 29% had intra-abdominal inflammatory disease, 25% had bacteremia, and 32% were intravenous drug users. Antibiotics alone were successful in 16/21 patients (76%), while 5 (24%) required subsequent CT-guided percutaneous drainage (PCD). Among 72 patients undergoing PCD, 32 (44%) had successful treatment, 12 (17%) required multiple procedures, and 28 (39%) underwent surgery after failed drainage. Primary surgical drainage was performed in 7 patients (7%). Mean hospital stay was 21 days, and overall mortality was 5%, lower than reported rates (5%-15%). First-line treatment for IPA includes antibiotics and PCD, with surgery reserved for complex cases, gas formation, neurological involvement, proximity to vertebrae or spinal hardware, or failure of initial treatment.