[Ischemic disorders of the large intestinal wall. Ischemic colitis and rectitis secondary to intrinsic vascular...

Ischaemic diseases of the large intestinal wall is a characteristic syndrome caused by vascular insufficiency of varying degrees. The ischaemia results from haemodynamic disturbances and often arises in spite of the patency of the vessels. The mucosa of the intestine is the tissue layer that is most vulnerable to ischaemia. Ischaemia of the colon occurs in the presence of a microbial flora that is often highly pathogenic, and hence the lesions rapidly become infected. For this reason the inflammatory features of the disease tend to conceal its vascular origin and ischaemic colitis has often been confused with other infectious, inflammatory, ulcero-haemorrhagic disorders of the large intestine. Although the syndrome may occur in any patient, it is much more common in elderly subjects with a history of arteriesclerosis and cardiac disease. Two main varieties can be identified, depending on the extent of the vascular insufficiency. In the first, the lesion may heal spontaneously or evolve towards fibrous strictures of the colonic wall; in the second, gangrenous necrosis of the colon or rectum may develope, the clinical picture of which has more in common with an "acute abdomen' than with ulcerative disease of the colon.