Recurrent Acute Pancreatitis Following Roux-en-Y Gastric Bypass (RYGB): The Afferent Loop Syndrome

Abstract

Introduction: Creation of a surgical gastrojejunostomy leaves a segment of small intestine (usually containing duodendum and proximal jejunum) proximal to the anastomosis called the afferent loop. Mechanical obstruction of the proximal limb leads to afferent loop syndrome. In this case, we describe a case of acute pancreatitis caused by afferent loop syndrome. Case Report: A 75-year-old male presented to the emergency department with nausea, vomiting, and abdominal pain. Past medical history was significant for gastroparesis, for which he underwent subtotal gastrectomy with a roux-en-Y gastric bypass (RYGB) in 2011. Since gastric bypass, the patient experienced 3 episodes of acute pancreatitis, all requiring inpatient management. On initial evaluation, his abdomen was tender and distended with a palpable right-sided abdominal mass. Laboratory evaluation showed lipase >6000 U/L, ALT 566 U/L, AST 738 U/L, total bilirubin 1.4 mg/dL, direct bilirubin 1 mg/dL, alkaline phosphatase 95 U/L, white blood cell count 13.4 k/uL. CT abdomen/pelvis with IV and oral contrast showed homogenous enhancement of pancreas with diffuse peripancreatic fat stranding. There was marked dilatation of the biliopancreatic duodenal limb up to 10 cm with transition in the distal duodenum (see image). He was diagnosed with afferent loop syndrome and “secondary” acute pancreatitis due to mechanical pressure-obstruction of the major papilla. The patient subsequently underwent exploratory laparotomy with lysis of adhesions, and duodenojejunostomy. Following this, the patient improved symptomatically with normalization in lipase and transaminases. No other cause of acute pancreatitis was identified. There have been no further episodes of acute pancreatitis at follow-up (4 months post-op). Discussion: Acute pancreatitis due to afferent loop syndrome is rare following RYGB. However, prompt diagnosis is crucial since relief from mechanical obstruction by surgery facilitates resolution of acute pancreatitis and is thus the treatment of choice.Figure 1