Diverticular Fistula

A diverticular fistula develops when chronic or recurrent sigmoid inflammation penetrates into an adjacent epithelial structure.

The commonest is colovesical fistula. Colovaginal, colocutaneous and less commonly coloenteric fistulas also occur.

A mature fistula usually represents structural disease and rarely resolves permanently with antibiotics alone.

Presentation depends on the target organ.

Bladder involvement causes pneumaturia, faecaluria and recurrent urinary infection.

Vaginal involvement causes passage of gas or stool vaginally.

Cutaneous disease produces chronic faeculent or purulent drainage from the abdominal wall.

Acute pain and fever suggest associated recurrent diverticulitis or abscess.

CT abdomen and pelvis: define the diseased sigmoid and fistulous relationship and exclude abscess or malignancy.

Colonoscopy should be performed once acute inflammation has settled to exclude colorectal cancer, particularly when a stricture or atypical imaging is present.

Definitive treatment in a fit symptomatic patient is elective resection of the diseased sigmoid colon and restoration of colorectal continuity. Fistula is a strong indication for resection.

Operate after acute sepsis has settled whenever possible because elective surgery permits better tissue planes, lower stoma rates and safer anastomosis.

The adjacent bladder or vagina often requires little or no resection once the inflammatory colon has been separated. Repair a clearly visible substantial defect with healthy tissue.

A primary colorectal anastomosis is appropriate in most elective cases.

Temporary diversion is reserved for high leak risk, major inflammation, poor tissue quality or significant physiological compromise.