DUODENUM / SMALL BOWEL (Robbins pp 802)

There are a range of things that can go wrong in the small bowel and they can be categorised into the following:

1. Congenital: atresia, stenosis, duplication, intussusception (one intestinal segment occurs within another), Meckel’s diverticulum (failure of involution of the vitelline duct, which connects the gut to the yolk sac).

2. Inflammatory:

   1. Enterocolitis: This is considered in Micro lectures.

3. Malabsorption syndromes

   1. Coeliac disease: This is malabsorption in the presence of gluten (i.e.: alcohol soluble protein component of wheat). I.e.: gluten acts as the “antigen”

      1. Aetiology / Pathogenesis: Gluten is exposed to small intestinal mucosa ≫ sensitised cytotoxic T cells accumulate in epithelium + sensitised T helper cells accumulate in lamina propria ≫cytokines are released ≫ these damage the enterocytes ≫ absorptive capability lost ≫ malabsorption. When gluten is removed ≫ malabsorption does not occur.

   2. Tropical Sprue: Malabsorption occurs after a gastrointestinal infection. E coli and Haemophilus have been implicated.

   3. Whipple’s disease: Malabsorption symptoms caused by Tropheryma whippelii. Microscopically, you can see distended macrophages in lamina propria with PAS positive granules and rod-shaped bacilli in them.

4. Tumours

Category: Pathology Notes