Abscesses are caused by the leakage of intestinal content through a tract into the peritoneal cavity. The infection is walled off by surrounding tissue, unlike free perforation, which causes generalized peritonitis. Extension of this tract through adjacent viscera or through the abdominal wall to the skin results in a fistula. The typical clinical presentation is fever and abdominal pain often with tenderness and abdominal mass.
Leukocytosis is the most common laboratory abnormality.
CT scan, barium enema, and ultrasonography are useful in the diagnosis of abdominal mass. Broad-spectrum antibiotic treatment and drainage are indicated. Simple drainage of an abscess may not provide adequate therapy because of persistent communication between the abscess cavity and intestinal lumen. In such circumstances, drainage may result in formation of an enterocutaneous fistula. Percutaneous drainage is usually carried out first under ultrasound or CT guidance.