Internal Hernia in the Retroantral Space Complicated by Acute Strangulated Small Bowel Necrosis: A Case Report of a Rare Postprandial Exercise-Induced Condition in an Adolescent

Background Congenital mesenteric hernia, a rare etiology of acute abdomen with an overall incidence of less than 1%, often requires intraoperative confirmation. This article reports a unique case of mesenteric hernia—retroantral space internal hernia—in an adolescent triggered by postprandial strenuous exercise and treated at the Emergency Surgery Department of Union Hospital, Tongji Medical College, Huazhong University of Science and Technology. Case Presentation A 17-year-old male presented with acute abdominal pain and distension following vigorous postprandial exercise. CT revealed an abnormal duodenal course. Emergency laparoscopic exploration confirmed herniation of 40 cm of ileum through the retroantral space into the right upper abdomen, with clockwise torsion leading to closed-loop strangulated necrosis. Approximately 1000 mL of bloody ascites was observed. Conversion to laparotomy enabled resection of the necrotic bowel. The remaining terminal ileum measured only 6 cm. To preserve ileocecal valve function, a side-to-side intestinal anastomosis was performed after informed consent was obtained. Postoperatively, the pelvic drainage tube remained clear without signs of anastomotic leakage, and the patient was discharged on day 7. Conclusion Emergency physicians should maintain a high suspicion for acute incarceration and bowel necrosis caused by mesenteric hernias in patients with acute abdomen. Although long-term risks require further validation, side-to-side anastomosis under critical ileocecal preservation may serve as a salvage strategy in high-risk anatomical scenarios.