Ischaemia of the colon due to interruption of its blood supply.
In most cases the underlying cause is thrombosis of the inferior mesenteric artery, embolisation of mural thrombus in atrial fibrillation, or non-occlusive infarction.
In around half the ischaemia is transient with damage confined to the mucosa and submucosa. The splenic flexure is most often affected due to the territories of the arteries supplying the bowel. If the blood supply is not restored, ischaemia progresses to gangrenous ischaemic colitis. The presentation and treatment is as for acute intestinal failure.
The patient presents with lower abdominal pain, nausea, vomiting and bloody diarrhoea. There is lower abdominal tenderness and guarding in the lower abdomen.
There is ischaemic loss of mucosa, ulceration and later healing with oedema and inflammatory infiltrate.
Ischaemic strictures may result from scarring at the splenic flexure or sigmoid colon. These are confirmed on barium studies and require resection.
A barium enema can be used to show oedema or mucosal sloughing. Bleeding into the bowel wall produces a thumb print appearance. Mesenteric angiography will demonstrate the stenosis or occlusion.
The condition generally is selflimiting within a few days with uncomplicated cases managed conservatively.