MIRA3006 Lecture Notes - Lecture 2: Colorectal Cancer, Coeliac Disease, Fecal Impaction
5 Aug 2018
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Document Summary
Usually the majority of cancers starts from pre-existing polyps that tend to be: Apple-core constricting lesions (annular carcinoma), tumor masses, nodal involvement, and metastases may be visualised. Xray and ct shows area of colon absence of contrast, stricture. Aneurysmal dilatation is based upon destruction of the bowel wall and the myenteric nerve. Thick walled infiltrating mass with aneurysmal dilatation without obstruction plexus. Several causes: mass, volvulus, invagination, fb, diverticulitis, parasites, fecal impaction, gallstone ileus. Ct is very useful in diagnosing high-grade obstruction (can be strangulation, 10%) but in low- grade small-bowel obstruction, 90%, ct is less accurate. Ct enteroclysis with positive enteral contrast material is better. High-grade obstruction with closed loop usually presents a radial array of dilated small bowel loops with the mesenteric vessels converging to a central point this is almost always due to a small bowel volvulus. In upright position is possible to observe a straight horizontal line between fluid and air.
