Teaching Case

A 50-year-old female patient presented to the emergency department with sudden onset epigastric pain and vomiting. The patient revealed tenderness and localized peritonitis in the epigastric region. Laboratory results included moderate leukocytosis and a C-reactive protein of 9.6 mg/dL.

The patient was admitted to the general surgical service with suspected perforated peptic ulcer and underwent a plain abdominal radiograph, which was unremarkable.
Subsequently, a CT of the abdomen with intravenous and oral contrast agents was performed, revealing a saccular outpouching in the medial aspect of the second portion of the duodenum (Fig. 1), surrounded by fluid and a small amount of extra-luminal air (Fig. 2). Associated thickening of the wall of the second and third duodenal portions was noticed. There was no evidence of oral contrast extravasation. Additionally, mild biliary duct dilation was observed (Fig. 1). Multiplanar reformations allowed to better depict the diverticulum location and its neck (Fig. 3).

An emergency surgical exploration revealed a perforated diverticulum of the second portion of the duodenum, with significant retroperitoneal phlegmon. She underwent a diverticulectomy, pyloric exclusion, gastrojejunostomy and a jejunostomy tube was placed.
The pathology report revealed a duodenal diverticulum demonstrating perforation with acute inflammation (diverticulitis).

The duodenum is the second most common location of intestinal diverticula, following the colon [1]. Although common, most duodenal diverticula are asymptomatic and incidentally found during routine imaging [1].
Perforation of a duodenal diverticulum is a rare complication, but also the most serious one, with mortality of up to 13% [2]. It usually develops as a result of diverticulitis [3]. Other causes include iatrogenic perforation and erosion due to foreign bodies or enterolith [3].
Clinical signs and symptoms are nonspecific, often resulting in delayed diagnosis [4]. Most often, acute onset of epigastric pain, nausea and vomiting are observed [1]. Inflammatory parameters are usually elevated. The clinical diagnosis requires a high index of suspicion [3].

Since duodenal diverticulum perforation occurs mostly in the retroperitoneal space, plain abdominal radiogram generally does not demonstrate presence of free air [5]. Ultrasound is also rarely informative.
Computed tomography (CT) is the most useful method to establish the diagnosis. It can identify the diverticulum and demonstrate wall thickening, adjacent fat stranding, periduodenal abscess and extra-luminal air [3, 5]. Coronal and sagittal reformatted images may be useful in identifying the diverticulum neck.
Most of duodenal diverticula (75%) are located within 2 cm of the ampulla of Vater, which is the reason why they may be associated with biliary and pancreatic duct obstruction, with consequent cholestasis and duct dilatation [1, 4].

The standard treatment for perforated diverticula is surgical intervention [2, 3]. If significant duodenal or retroperitoneal inflammation is present, more complex procedures, besides diverticulectomy, might be required [2]. Non-operative management can be an alternative to surgery in selected patients [2].