Teaching Case

A previously healthy 75-year-old male patient was admitted to the emergency department with a history of 11 hours duration of acute abdominal pain and a fever of 38,5 °C. Physical examination revealed abdominal tenderness, especially on the lower left abdomen. Besides minor leukocytosis (11,1x10^9/L), blood levels were normal

An emergency contrast CT scan of the abdomen in the portal venous phase was performed due to suspicion of acute colonic diverticulitis.  

The CT showed an approximately 9 x 8 cm duodenal diverticulum originating from the descending part of the duodenum, in close relation to the papilla of vater (fig. 1). Signs of inflammation and perforation of the diverticulum were shown with stranding and air accumulation around it. Furthermore, there was retroperitoneal free air accumulating around the right kidney (fig. 2) but no stranding. Dilatation of the common bile duct and the pancreatic duct (“double duct sign”), as well as intrahepatic bile stasis, was shown (fig. 3).

There were no stones in the common bile duct or other obstructive tumors. Findings were coherent with inflammation and perforation of the duodenal diverticulum causing obstructive jaundice and the diagnosis of Lemmel syndrome was made.

Background

Duodenal diverticula are saccular outpouchings of the duodenal mucosa. After colonic diverticula, the second most common localization of intestinal diverticula is the duodenal diverticula with a prevalence of up to 22% [1]. Duodenal diverticula can be classified as congenital or acquired. More common are acquired diverticula, consisting of extraluminal outpouching of only mucosa and submucosa due to weakness of the muscularis and the serosa with aging [1-2]. 

Duodenal diverticula are mostly asymptomatic. Therefore, the diagnosis is often made as an incidental finding in endoscopy or radiologic imaging, such as ultrasound, CT imaging, or MRCP. The considered gold standard method is endoscopy [3]. Complications are rare and include ulcerations, bleeding, perforation, and pancreaticobiliary obstruction [2].

Obstructive biliary stasis without the presence of gallstones or tumors is also known as Lemmel syndrome. The most common cause of Lemmel syndrome is a periampullary duodenal diverticula within 2-3 cm of the ampulla of vater [3]. Obstructive biliary stasis can develop either with external compression from the periampullary diverticula to the bile duct and ampulla of vater or due to chronic inflammation leading to fibrosis and eventually stricture of the ampulla. 

Perforation of duodenal diverticula is rare. The triggering factor is often food retention and diverticulitis leading to ischaemia. Other causes are enterolithiasis, ulceration, trauma or iatrogenic perforation [1, 4]. 

Clinical perspective

Patients with Lemmel syndrome may present with elevated bilirubin and liver enzymes, abdominal pain and fever, which often requires CT imaging to differentiate between the clinical diagnoses. 

In case of perforation, patients may present with nonspecific symptoms such as upper abdominal pain and vomiting [1, 4]. 

Imaging perspective

To make the diagnosis of Lemmel syndrome, imaging will reveal a focal outpouching of the duodenum in close relation to the common bile duct, causing obstructive biliary stasis with “double duct sign” and intrahepatic bile stasis.

In the case of perforation, retroperitoneal air accumulation is often seen, due to the common location of duodenal diverticula in the descending and horizontal part of the duodenum (2nd and 3^rd sections) [1].

Outcome

With Lemmel syndrome, the treatment depends on the patient’s clinic and can vary between conservative and radical surgical interventions [2]. In case of perforation, acute surgical treatment may be required.

Take Home Message/ Teaching Points

Duodenal diverticula rarely trigger clinical symptoms but can become symptomatic with inflammation or perforation. Furthermore, Lemmel Syndrome must be considered in patients with biliary stasis, to avoid overdiagnosis of malignancy.

Written informed patient consent for publication has been obtained.