Case report: Lemmel syndrome-aggravated by consumption of fatty food.

Introduction and importance: One of the very rare causes of obstructive jaundice, Lemmel's syndrome, is caused due to biliary mechanical compression by a juxtapapillary diverticulum. It is defined as obstructive jaundice due to juxtapapillary diverticulum in the absence of cholelithiasis, periampullary tumours, or other detectable obstacles. It is an extremely rare syndrome; therefore, studies need to be done for proper diagnosis and management. Case presentation: Our patient, a 73-year-old woman, gave a history of recent acute right hypochondriac pain that had subsided the day before. Lab investigations were performed and liver enzymes were found to be significantly raised. An endoscopy followed by an endoscopic ultrasound was performed for further diagnosis, which showed the diverticulum outpouching from the duodenum. MRCP was then performed, which revealed a dilated common bile duct and common hepatic duct, with tapering at the distal end, most likely to be a stricture. Lemmel syndrome was identified based on the clinical presentation and imaging results. A dilated common bile duct, and two large duodenal diverticula with interdiverticular papilla was discovered during the patient's endoscopic ultrasound, which was performed by the gastrointestinal team. Clinical discussion: Duodenal diverticula are the second most common site of diverticula after the colon with an incidence of 1-5% in radiological series. Lemmel's syndrome is a rare cause of obstructive jaundice associated with juxtapapillary diverticulum. With a low incidence rate, only a few cases of Lemmel's syndrome are reported with the first case reported in 1934 by Lemmel. Imaging techniques such as barium meal, EUS, ERCP, or magnetic resonance cholangiopancreatography are used to confirm the diagnosis. Our observations demonstrate that the diverticulum, which is often found on the medial wall of the second half of the duodenum and contains bezoar, compresses the distal common bile duct laterally. Nowadays, ERCP and EUS are used to confirm the diagnosis. Only symptomatic periampullary duodenal diverticulum (PDD) requires conservative or surgical therapy. The first line of treatment for biliopancreatic PDD problems is endoscopic sphincterotomy, which is 95% effective. Conclusion: Lemmel syndrome occurs due to the compression of the common bile duct by a duodenal diverticulum. Imaging, including CT scans, and MRCP are important for the diagnosis of this syndrome. Treatment modalities are not the same for each patient, however.