Distal duodenum

In all species, the small intestine is the main site for simultaneous hydrolysis of fats, proteins, and carbohydrates by selective enzymes and absorption of the resulting nutrients. It consists of three sequential sections duodenum, jejunum and ileum, each with villi and mucosal linings. During the process, the pH of the digesta is raised from that of the stomach, to near neutrality over the length of the small intestine. In swine, the pH profile is as follows stomach, 2.4 proximal duodenum, 6.1 distal duodenum, 6.8 proximal jejunum, 7.4 distal jejunum, 7.4 and ileum, 7.5. In sheep, the profile is abomasum, 2.0 proximal duodenum, 2.5 distal duodenum, 3.5 proximal jejunum, 3.6 distal jejunum, 4.7 and ileum, 8.0 (48). Several types of contractive and peristaltic actions mix and move the digesta down the intestine. The lower pH at the proximal duodenum of ruminants plays a critical part in fatty acid reabsorption. Hydrolysis of triacylglycerols by pancreatic lipase... 

Such, J., Guardiola, J.V., de Juan, J., Casellas, JA., Pascual, S., Apmi-cio, J.R., Sola-Vera, J., Perez-Mateo, M. Ultrastructural characteristics of distal duodenum mucosa in patients with cirrhosis. Eur. J. Gastroenterol. Hepatol. 2002 14 371-376... 

There were no differences in the incidence of middle and distal duodenum lesions (14). Esophageal ulceration with bleeding was reported in an elderly woman with esophageal dysmotility (SEDA-17, 112). Esophageal symptoms and esophageal ulcers were reported with naproxen sodium tablets (as opposed to capsules) for over-the-counter use (SEDA-22, 111). Naproxen did not cause reflux and had no significant effect on motility in healthy subjects (15). 

Fig. 1.11a,b. Midgut volvulus in a 7-day-old girl with bilious vomiting. Upper gastrointestinal series. Anteroposterior (a) and lateral projections (b). The distal duodenum courses anteriorly and tapers to a beaked obstruction (arrow). No contrast is observed beyond the obstruction, but there is distal air indicating a recent complete obstruction... 

Orally administered peppermint oil was used in a randomized trial in 430 patients undergoing a double-contrast barium meal examination, without other antispasmodics. A reduction in spasms of the esophagus, lower stomach, and duodenal bulb was found, along with an inhibition of barium flow to the distal duodenum and an improvement of diagnostic quality (Shigeaki et al., 2006). 

Gastrinoma-induced ulcers have the same features as others but may be observed in the more distal duodenum. 

These include ulcers in the distal duodenum, the presence of a double pyloric canal (Fig. 5.8b,c), or multiple recurrent anastomotic ulcers. Other findings include a non-dilated non-obstructed stomach filled with diluted barium due to hypersecretion, dilatation of the duodenum and proximal small bowel, sluggish gastric peristalsis, and thickening of gastric and duodenal folds (Berg and Wolfe 1991 Hirschowitz 1997). 

The radiological findings of Crohn s disease of the distal duodenum are similar to those of the rest of the small bowel and terminal ileum, with skip lesions, cobble stoning, asymmetry, and in the more advanced stage of the disease, strictures causing eccentric narrowing. Other features of Crohn s disease such as sinuses, fistulas, sacculations, and inflammatory pseudopolyps are uncommon in the duodenum (Fielding et al. 1970 Levine 1987 Hizawa etal. 1994). 

Fig. 5.13a,b. Eosinophilic gastroenteritis a Note thickening and straightening of the folds of the descending duodenum together with jejunal involvement, b More prominent involvement of the distal duodenum and jejunum (different patient)... 

Fig. 5. 21a,b. Brunner s gland adenoma a CECT shows an intussusception in the distal duodenum, b Barium follow-through performed later shows a large filling defect arising from the first part of the duodenum which at operation was confirmed as being due to a Brunner s gland adenoma... 

The arterial supply to the stomach and upper duodenum is from the coeliac axis. The superior mesenteric artery supplies the mid and distal duodenum. The coeliac axis arises from the aorta anteriorly at the... 

The superior mesenteric artery (SMA) has its origin approximately 1 cm inferior to the coeliac axis on the anterior aspect of the aorta. Its inferior pancreaticoduodenal branches anastomose with the superior pancreaticoduodenal artery to supply the mid and distal duodenum. 

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