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A 45-year-woman was admitted through emergency medical services with sudden severe upper abdominal pain in the epigastrium with radiation to the back. The pain in the upper abdomen was associated with recurrent bouts of bilious vomiting. She denied any other gastrointestinal symptoms. She had similar episodes of pain 6 months earlier and was diagnosed with acute pancreatitis (AP) in another institution and managed conservatively. She was clinically stable with tenderness in the epigastrium. Her laboratory parameters were normal except for raised amylase (950 U/L) and lipase (1250 U/L). Ultrasound of the abdomen revealed a bulky oedematous pancreas with minimal free fluid. There were no gall stones and the common bile duct was normal. A working diagnosis of mild AP was made as there was no evidence of organ failure. She was managed in the intensive care unit for 48 hours with intravenous fluids, enteral nutrition and later moved to a ward. Her lipid profile, liver function tests, serum creatinine, serum calcium, serum parathyroid hormone levels and serum IgG 4 levels were normal. Post recovery, magnetic resonance cholangiopancreatography (MRCP) was performed to further investigate the aetiology of the pancreatitis and this revealed a duct arising from the ventral aspect of the main pancreatic duct descending down initially and then ascending upwards forming a loop in a reverse S shape that then opened into the minor papilla (figure 1), which was suggestive of ansa pancreatica. The patient was managed conservatively and discharged.
During embryogenesis due to obliteration of dorsal pancreatic duct at the confluence with the ventral duct, the proximal portion of the dorsal duct communicates with the inferior aspect of the ventral duct, forming a new accessory duct which courses in a reverse ‘S’ character, terminating in the minor papilla1 (figure 2). In ansa pancreatica the drainage through the minor papilla is inadequate due to its oblique communication with the main duct, leading to recurrent AP.1
Hayashi et al in a retrospective analysis demonstrated ansa pancreatica as a predisposing factor for the onset of recurrent AP. The frequency of ansa pancreatica was highest in patients with alcoholic pancreatitis.2 The exact link between alcohol consumption and ansa pancreatica leading to recurrent AP is unknown. To conclude, MRCP is an important tool to identify and define this rare congenital pancreatic ductal anomaly.
Magnetic resonance cholangiopancreatography (MRCP) is a non-invasive method to obtain a pancreatogram, helping to identify various pancreatic ductal anomalies.
MRCP is an important investigation which should be included in evaluation of idiopathic recurrent acute pancreatitis.
The typical reverse S-shaped accessory pancreatic duct draining in the minor papilla on imaging is classical of ansa pancreatica.
Contributors VG wrote the manuscript. PG edited the image and drew a figure explaining the anomaly. NP provided the image and helped in finalising the manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
Patient consent for publication Obtained.
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