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| Ischemic Colitis |
| Etiology •Ischemic colitis is caused by hypoxemia to the terminal vascular distribution of the intestines |
| Pathogenesis •Ischemic colitis occurs in a setting of underlying vascular compromise due to arteriosclerosis or chronic hypertension. •In the mesenteric blood flow there is a preferential shunting of blood from the superficial intestinal mucosa to the deeper mucosa •This shunting of oxygenated blood leaves the superficial mucosa at risk to ischemic damage whenever there is a decrease in vascular perfusion such as occurs during heart failure, shock, sepsis, etc. particularly when superimposed on a circulation already compromised by underlying vascular disease. •This causes focal lesions in contrast to large vessel compromise which leads to segmental infarction •Focal ischemia occurs preferentially where collateral circulation is poorest, accounting for its infrequency in the small intestine and its preference for the splenic flexure of the colon, |
| Epidemiology •Ischemic colitis is a disease of older people •It has an equal male/female distribution •There is a strong association with arteriosclerosis and hypertension •It can occur in younger individuals, primarily associated with an underlying vasculopathy |
| General Gross Description •Lesions are seen in descending order of frequency in the splenic flexure, descending and transverse colon •Mild lesions will show mucosal reddening, hemorrhage and mild edema. More severe lesions will show evidence of ulceration with the depth depending on the severity of the vascular insult •Severe lesion in the healing phase can show evidence of stricture formation |
| General Microscopic Description •Mild lesions show dilated capillaries, hemorrhage, superficial epithelial necrosis and variable neutrophils •In the healing phase evidence of epithelial regeneration and variable fibroplasia are seen •Severe ischemic insults can result in full thickness mucosal necrosis making the lesion difficult to distinguish from other necrotizing colitides •These cases will have significant ulceration and can have significant amounts of scarring as repair takes place |
| Clinical Correlation •Ischemic colitis presents with the sudden onset of bleeding and abdominal pain usually in a patient over 50yrs. with a background of arteriosclerosis, hypertension or diabetes •The most common problem in differential diagnosis is with inflammatory bowel disease, active phase. •Colonic biopsy is usually needed to establish the diagnosis. •Therapy is primarily medical, aimed at restoring adequate circulation. Surgery is restricted to cases of perforation or stricture |
| References •Gastrointestinal Pathology, Fenoglio-Preiser, CM, et al, Raven Press, New York 1989 pp 639-643 |
| Ischemic Colitis |
| Synopsis by: Martin Nadel, M.D. (T67000M40600)[358] |
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