Teaching Case

Melena and anemia in an elderly male patient.

Single episode of melena, and anemia, in an 82 year old male. Small bowel meal performed as other investigations did not demonstrate the source of the bleeding.

Diverticula in the small bowel are rarer than in the large bowel or duodenum. In most cases they are seen in patients of 40 years or older, with a male predominance. They are seven times commoner in the jejunum than in the ileum. Usually they are acquired false diverticula, due to herniation of the mucosa and submucosa through weaker areas of the musculature, usually where the mesenteric vessels enter the bowel wall. For this reason they are located in the mesenteric border of the small bowel. They are usually asymptomatic, but in 40% of cases can cause non-specific symptoms, such as sense of abdominal heaviness, flatus and abdominal discomfort. They rarely cause complications (occurring in 10% of all patients), as they commonly have a large neck, and their content is almost always liquid (they rarely contain food debris.), and these factors prevent obstruction. Complications include perforation, hemorrhage and malabsorption due to subsequent infection. Diverticulosis can be recognized on the small bowel examination, either through a small bowel meal or enema, with the former examination giving the better results in their visualization. Erect films, with or without barium, will show fluid levels within the diverticula and may simulate small bowel obstruction, except for the fact that there tend to be numerous short fluid levels all of similar length and that no dilated bowel is seen on the supine film. The diverticula themselves are commonly seen as round, oval or flask-shaped structures protruding from the mesenteric border of the small bowel. The most reliable method of diagnosis is to demonstrate mucosa leading into the neck of individual diverticula. The differential diagnosis includes large small bowel ulcers, or necrotic excavating lesions of tumors. If no inflammation is present, the mucosal folds next to the diverticula are normal and their wall is thin and regular. If the diagnosis is not confirmed by a small bowel meal or enema, US or CT may allow to visualize the diverticulum together with the thickening of the diverticular wall and the infiltration through the peridiverticular mesenteric fat and enlarged mesenteric lymphnodes may be seen. If the diverticular lumen is occluded, only the mesenteric abnormalities listed above are seen, and in this case the differential diagnosis is mesenteric or epiploic inflammation. Occasionally, accurate localization of the diverticula may be important because, if they are confined to one loop or short segment of jejunum, resection with cure may be possible and in selected cases intubation of the lower jejunum or ileum may be useful by showing segments of bowel affected by diverticulosis. However, since these patients are usually elderly and their symptoms can be controlled by antibiotics and iron replacement therapy, this localization is not required in most cases.