EP 182 A Rare Cause of Closed-Loop Obstruction: Caecal Volvulus within a Petersen’s Hernia following Gastric Bypass

Keywords

Caecal volvulus, Petersen’s hernia, Gastric bypass, Closed-loop obstruction, Internal hernia, Acute abdomen

Background

Internal herniation through Petersen’s defect is a recognised late complication of Roux-en-Y gastric bypass, usually involving small bowel loops. Caecal volvulus within a Petersen’s hernia is extremely rare, with few cases reported. Such presentations pose diagnostic and operative challenges due to altered post-bypass anatomy and atypical imaging features.

Case Presentation

A 41-year-old woman presented with sudden-onset severe abdominal pain, vomiting, and absolute constipation. She had a history of Roux-en-Y gastric bypass and cholecystectomy. Examination revealed a distended, rigid abdomen with peritonism and elevated inflammatory markers. CT imaging demonstrated a markedly dilated, gas- and fluid-filled ahaustral caecum (maximum diameter 9.4 cm) displaced into the left upper quadrant with twisting of the mesentery, engorged vessels, and features of closed-loop obstruction.

Emergency laparotomy revealed a grossly distended caecum twisted clockwise on its mesentery within a large Petersen’s defect. The terminal ileum was uninvolved. Moderate pelvic pus was present without perforation. The remaining colon was viable. A right hemicolectomy with stapled ileocolic anastomosis and closure of the Petersen’s defect was performed.

Discussion and Conclusion

Caecal volvulus within a Petersen’s hernia is an exceptionally rare but life-threatening cause of intestinal obstruction. Post-bariatric anatomical distortion may obscure diagnosis. Awareness of this entity, detailed CT interpretation, and prompt operative management with mesenteric defect closure are critical to prevent ischemia and improve outcomes in post-gastric bypass patients presenting with acute abdomen.