Colocutaneous Fistula

A colocutaneous fistula is an abnormal communication between colon and skin.

It may follow abdominal surgery, percutaneous drainage of a diverticular abscess, Crohn disease, malignancy, trauma or spontaneous perforated diverticular disease.

The fistula can provide effective external drainage of an infected colonic process while leaving the diseased bowel unresolved.

Patients develop persistent purulent, faeculent or gaseous discharge from an abdominal wound or previous drain site.

Output from colonic fistulas is often lower than proximal small bowel fistulas, so severe fluid depletion is less common.

Persistent fever, pain or increasing discharge suggests an associated undrained collection or continuing distal obstruction.

CT abdomen and pelvis with enteric and IV contrast where appropriate: define the diseased bowel, fistulous tract, collections and distal obstruction.

Colonoscopy after acute inflammation settles is important when malignancy or Crohn disease has not been excluded.

Control sepsis first.

Drain associated collections, protect surrounding skin and correct nutritional deficits.

Antibiotics are used for active infection, not simply because a mature fistula remains open.

A fistula caused by diverticular disease usually requires elective sigmoid resection with removal of the diseased fistula bearing bowel once inflammation has settled.

Do not simply excise or close the external tract while leaving the pathological colon in place.

Primary colorectal anastomosis is appropriate when sepsis has resolved and tissue quality is satisfactory.

Urgent surgery is required for generalised peritonitis, uncontrolled sepsis, distal obstruction or another failure of source control.