Colostomy for Bowel Diversion in Aggressive Diverticulitis With Colovesical and Colocutaneous Fistulae: A Case Report.

Fistulizing diverticulitis is an uncommon and aggressive manifestation of diverticular disease. Most patients develop a single fistula; multiple synchronous fistulae are less commonly reported. We present a case of a 55-year-old man with a history of anorectal fistula repair who presented with recurrent abdominal pain, urinary symptoms, and weight loss. Imaging revealed complicated sigmoid diverticulitis with multiple fistulae involving the bladder, rectum, and abdominal wall. Initial management included abscess drainage and a diverting transverse loop colostomy, which successfully controlled sepsis and halted fistula output. After clinical optimization, the patient underwent open sigmoid resection, colovesical fistula takedown, and bladder repair, followed by colostomy reversal. At follow-up, he remained asymptomatic with normal bowel function. This case highlights an unusual presentation of complicated diverticulitis and demonstrates the effectiveness of a staged approach using transverse loop colostomy prior to definitive resection.