A duodenal diverticulum refers to a pouch-like protrusion formed by a portion of the intestinal wall extending outward from the lumen. Its diameter can range from a few millimeters to several centimeters, most commonly occurring in the descending portion of the duodenum. Diverticula may be solitary or multiple. Approximately 75% of these diverticula are located within 2 cm of the duodenal papilla, often referred to as periampullary diverticula. The prevalence of duodenal diverticula increases with age, with detection rates of around 6% through upper gastrointestinal barium studies and autopsy findings ranging from 10% to 20%.
Pathology
The majority of duodenal diverticula arise from congenital defects in the muscular layer of the local duodenal wall. The diverticular wall is primarily composed of mucosa, submucosa, and connective tissue, with minimal muscular components, and is classified as a primary or false diverticulum. In the region near the duodenal papilla, where blood vessels, bile ducts, and pancreatic ducts penetrate the intestinal wall, the muscular layer is thinner, which, along with increased intraluminal pressure, may lead to the outward protrusion of mucosa, forming a diverticulum. A type of diverticulum known as secondary or true diverticulum, which is rare in clinical practice, arises when the entire intestinal wall forms the diverticulum due to inflammation, adhesions, or scar-induced traction on the duodenal wall.
When the neck of the diverticulum is narrow, food entering the diverticulum may not pass easily, potentially forming enteroliths. Poor drainage and bacterial overgrowth may lead to diverticulitis, ulceration, bleeding, or even perforation. Patients with periampullary diverticula often experience a higher incidence of biliary stones, which may also compress the common bile duct and pancreatic duct, triggering episodes of cholangitis or pancreatitis.
Clinical Manifestations
The vast majority of duodenal diverticula are asymptomatic, with clinical symptoms occurring in only about 5% of patients. Symptoms may include upper abdominal pain, nausea, belching, and postprandial exacerbation of discomfort. In cases of diverticulitis, pain may occur in the midepigastric or umbilical region, radiating to the right upper abdomen or back, along with nausea, fever, and elevated white blood cell count. Physical examination may reveal upper abdominal tenderness. Perforation of a diverticulum in the descending portion of the duodenum into the retroperitoneal space may result in severe retroperitoneal infections. Diverticula near the papilla may be complicated by biliary infections, cholelithiasis, obstructive jaundice, or pancreatitis, presenting with corresponding symptoms.
Diagnosis
Most duodenal diverticula lack specific symptoms, making diagnosis challenging based solely on clinical presentation. Fiberoptic duodenoscopy has a relatively high diagnostic rate, providing accurate assessment of the location and size of the diverticula. Ultrasound and CT imaging may detect duodenal diverticula in the pancreas, as they often contain gas, fluid, or food debris. However, they may sometimes be misdiagnosed as pancreatic pseudocysts or abscesses.
Treatment
Asymptomatic diverticula do not require treatment. In cases where symptoms are confirmed to be caused by diverticula, treatments such as dietary modification, anti-inflammatory medications, acid suppression, and antispasmodic therapies may be applied. Surgical indications for duodenal diverticula should be carefully considered and include perforation with peritonitis, massive bleeding, foreign body formation within the diverticulum, diverticulum-induced cholangitis or pancreatitis, and cases in which symptoms persist despite medical therapy.
Common surgical procedures include diverticulectomy. For smaller diverticula, invagination and suture may be performed. In cases where periampullary or multiple diverticula make resection difficult, gastrointestinal bypass surgeries, such as Billroth II partial gastrectomy with exclusion of the duodenum, may be considered.