Unforeseen consequence of colovesical fistula in diverticulitis presenting as septic cellulitis: A case report

BACKGROUND: Colovesical fistula (CVF) is an uncommon but serious complication most often linked to diverticular disease of the colon. Its diagnosis can be at times challenging as the symptoms are nonspecific, and timely intervention is crucial to avoid morbidity. CASE SUMMARY: A 65-year-old Indian male was admitted with right lower limb cellulitis and was in septic shock. Despite initial management, he remained oliguric with persistent loose stools. On post-fasciotomy day 4, fecaluria was noted, prompting suspicion of a bowel-urinary tract fistula. Microscopic urine examination confirmed fecal matter. A computed tomography urogram with cystogram revealed a CVF at the sigmoid colon, likely secondary to diverticulitis. Baseline carcinoembryonic antigen levels were normal. An exploratory laparotomy was performed, which revealed dense adhesions between the sigmoid colon and bladder were noted, and the findings were consistent with diverticulitis though no discrete diverticulum was separately visualized. The fistulous tract was excised (frozen section was negative for malignancy), a two-layer bladder repair was performed, and the affected sigmoid colon segment was resected using a Hartmann's procedure. Multiple bladder washes were also done. Postoperatively, the patient recovered well, with resolution of oliguria and diarrhea. He was discharged on postoperative day 8. Histopathology confirmed diverticulitis without malignancy. A successful stoma reversal occurred 2 months later, and he remained symptom-free at the 6-month follow-up. CONCLUSION: CVF should be considered in cases of persistent urinary symptoms or fecaluria, particularly in patients with risk factors such as older age and diverticular disease, even in regions with low incidence of colonic diverticula. Early diagnosis using imaging modalities and prompt surgical management are key to favorable outcomes.