Small Intestine MCQs

Proximal small intestine fistulas will have high output → so metabolic and electrolyte complications are more common with proximal fistula The maximum malnutrition is caused by duodenal fistulas. Although gastric and duodenal fistulas receive almost the same food and enzymes, duodenum receives extra bile from gallbladder and pancreatic enzymes from pancreas hence duodenal fistula are more notorious for nutritional complications. Fistulas which are difficult to heal: F - foreign body in tract R - radiotherapy I - inflammatory bowel disease E - epithelialised tract N - neoplasia D - distal obstruction S - short fistulous tract ( Principles of management of enterocutaneous fistula (SNAP) S - elimination of Sepsis and skin protection N - Nutrition - a period of parenteral nutrition may well be required. A - Anatomical assessment P - definitive Planned surgery

If the jejunum is resected, the ileum can assume all the required absorptive functions, but resection of the terminal ileum will result in a diminished bile salt pool, vitamin B12 deficiency and may lead to deficiency of the fat-soluble vitamins A, D, E and K. The ileum also plays an important role in water absorption, possibly because the tightness of the intercellular junctions supports a concentration gradient across its lumen. Significant ileal resection therefore commonly results in very troublesome diarrhea. The small intestine plays an important role in the metabolism of plasma lipoproteins, as it is the main site of synthesis of high-density, low-density and very low-density lipoproteins (HDL, LDL, VLDL).

In the gastrointestinal tract, especially the small intestine, they secrete excess 5-HT , which is rapidly metabolized by the liver. In the presence of liver metastases, NET metastases secrete 5-HT into the IVC, avoiding hepatic first-pass metabolism and leading to symptoms of 5-HT excess, known as carcinoid syndrome . The cardinal features are sweating, flushing, bronchospasm and restrictive cardiomyopathy secondary to fibrotic right heart valvular disease (Hedinger syndrome ).

Features of obstruction In high small bowel obstruction, vomiting occurs early, is profuse and causes rapid dehydration. Distension is minimal with little evidence of dilated small bowel loops on abdominal radiography In low small bowel obstruction, pain is predominant with central distension. Vomiting is delayed. Multiple dilated small bowel loops are seen on radiography In large bowel obstruction, distension is early and pronounced. Pain is less severe and vomiting and dehydration are later features. The colon proximal to the obstruction is distended on abdominal radiography. The small bowel will be dilated if the ileocaecal valve is incompetent. Reference : Bailey & Love's short practice of surgery, chapter: 78, Edition: 28th, Pg: 1381

The length of the small bowel varies from 300 to 850 cm between the duodenojejunal (DJ) flexure to the ileocaecal valve . It is notoriously difficult to establish the length of the small intestine, and estimates gathered at surgery, at postmortem and during radiological investigations may vary widely, even in the same individual. In addition, there is considerable inter-individual variability and the small intestine has been said to be longer in men. Reference : Bailey & Love's short practice of surgery, chapter: 74, Edition: 28th, Pg: 1306

Carcinoid tumours These neuroendocrine tumours occur throughout the gastrointestinal tract, most commonly in the appendix, ileum and rectum in decreasing order of frequency. Appendicular carcinoid tumours are commonly noted as an incidental finding at appendicectomy, and are said to occur in approximately 2% of appendices removed surgically. The tumour arises from Kulchitsky cells at the base of intestinal crypts (of Lieberkuhn). Carcinoid tumours can produce a number of vasoactive peptides, most commonly 5-hydroxytryptamine (serotonin), but also histamine, prostaglandins and kallikrein. Plasma markers of tumour bulk, such as chromogranin A concentrations, may be useful markers of disease recurrence, as well as of prognostic value. CARCINOID TUMOR OF THE SMALL INTESTINE Reference : Bailey & Love's short practice of surgery, chapter: 74, Edition: 28th, Pg: 1310

Crohn Disease Crohn disease is a chronic, transmural inflammatory disease of the gastrointestinal tract for which the definitive cause is unknown, although a combination of genetic and environmental factors has been implicated. Crohn disease can involve any part of the alimentary tract from the mouth to the anus but most commonly affects the small intestine and colon. The most common clinical manifestations are abdominal pain, diarrhoea, and weight loss. Crohn disease can be complicated by intestinal obstruction or localized perforation with fistula formation. Medical and surgical treatments are palliative; however, operative therapy can provide effective symptomatic relief for patients with complications from Crohn disease and produces a reasonable long-term benefit. Reference : Sabiston textbook of Surgery, chapter: 50, Edition: 21 st , Pg: 1258

Crohn Disease Crohn disease is a chronic, transmural inflammatory disease of the gastrointestinal tract for which the definitive cause is unknown, although a combination of genetic and environmental factors has been implicated. Crohn disease can involve any part of the alimentary tract from the mouth to the anus but most commonly affects the small intestine and colon. The most common clinical manifestations are abdominal pain, diarrhoea, and weight loss. Crohn disease can be complicated by intestinal obstruction or localized perforation with fistula formation. Medical and surgical treatments are palliative; however, operative therapy can provide effective symptomatic relief for patients with complications from Crohn disease and produces a reasonable long-term benefit. Reference : Sabiston textbook of Surgery, chapter: 50, Edition: 21 st , Pg: 1258