A Case Report of Iliopsoas Abscess Secondary to Small Bowel Fistula

Abstract

Iliopsoas abscesses (IPAs) are rare infections in the musculature that can be difficult to diagnose due to nonspecific presentations. These abscesses are most commonly caused by either the hematogenous spread of a separate infectious source in the body or secondary to Crohn's disease and are typically treated with antibiotic therapy and percutaneous drainage. For cases complicated by bowel disease, multiloculated psoas abscess, or gas-forming organisms, surgical drainage may be indicated. We present the case of an 81-year-old female with a history of colon cancer status post-cecum resection who presented with back pain, thigh pain, and constipation. Computerized tomography imaging showed concurrent small bowel obstruction and a right IPA extending down to the right thigh. Laparoscopic exploration revealed a small bowel fistulization to the right iliopsoas as the source of infection. Resection of the small bowel and surgical incision and drainage of the abscess were necessary for her treatment. The patient was discharged with vacuum-assisted closure of her wound after a hospital course complicated with chronic diarrhea. Bowel fistulization should be considered a potential cause of IPAs in patients with a complicated gastrointestinal history.

Keywords: atypical back pain; fistulization; iliopsoas abscess; incision and drainage of abscess; small bowel obstruction.

Figure 1. CT of the abdomen without contrast showing air, fluid, and abnormal thickening of the right iliopsoas musculature extending down to the right thigh, concerning for abscess.

Figure 2. CT of the abdomen without contrast showing dilatation of the small bowel loops due to small bowel obstruction.

Figure 3. CT of the right lower extremity without contrast showing inflammatory changes with soft-tissue air tracking from the right iliopsoas musculature to the right mid-quadriceps musculature. No drainable, well-defined fluid collection was identified.