Asian Journal of Case Reports in Surgery

Afferent loop syndrome is an uncommon but potentially life-threatening complication of upper gastrointestinal reconstructive surgery and is a rare cause of severe acute pancreatitis after one-anastomosis gastric bypass. This case report describes a 43-year-old man with previous one-anastomosis gastric bypass who presented approximately 24 hours after symptom onset with severe epigastric and mesogastric pain, nausea, vomiting, reduced oral intake, and an incarcerated post-incisional hernia. Computed tomography showed a strangulated proximal jejunal loop with marked dilatation of the remnant stomach, duodenum, and proximal jejunum, without radiological evidence of pancreatitis. Emergency exploratory laparotomy was performed two hours after admission, and bowel viability recovered after reduction. During the first postoperative day, the patient developed persistent abdominal pain, oliguria, tachycardia, progressive metabolic acidosis, acute kidney injury, severe systemic inflammation, and clinical deterioration. Re-exploration revealed abundant serohaemorrhagic peritoneal fluid, extensive retroperitoneal inflammatory changes around the pancreas, and markedly elevated peritoneal amylase and lipase levels, supporting severe acute pancreatitis secondary to afferent loop syndrome. Despite surgical decompression, negative-pressure temporary abdominal closure, vasopressor support, mechanical ventilation, and intensive multidisciplinary management, the patient developed refractory shock and multi-organ failure and died approximately 39 hours after admission. This case emphasises the need to consider biliopancreatic limb obstruction in patients with altered upper gastrointestinal anatomy who present with bowel obstruction or unexplained metabolic deterioration.