Key points

• Acute ischaemic colitis can be due to occlusive or non-occlusive causes

• A high index of suspicion should be present in elderly patients presenting with sudden abdominal pain and bloody diarrhoea

• Computed tomography (CT) scan may show a ‘halo sign’ and also rule out other abnormalities

• D-Lactate is more specific for intestinal ischaemia than L-Lactate

• Angiography and lysis may be considered in early cases with no sign of peritonitis

• In case of bowel resection primary anastomosis is best avoided and a re-look laparotomy recommended

• Postaneurysm repair colitis can be prevented by selective reimplantaion of the inferior mesenteric artery (IMA) in high risk cases

Introduction

Ischaemic colitis is the result of an event that leads to a reduction in colonic blood flow sufficient to cause ischaemia or infarction of the colonic wall but not sufficient to produce full thickness infarction and perforation.

The term ischaemic colitis was first introduced by Marston et al. in 1966. It is commonly due to acute thrombosis or embolism of the superior mesenteric artery (SMA) or IMA, causing compromise of the colonic blood supply or due to hypotension causing hypo­perfusion and ischaemia.

The term is often used for cases where full thickness infarction is present acutely but this usage is incorrect – not all ischaemic colons have ischaemic colitis, although the two may coexist if the involvement is patchy.

Pathophysiology

The following causes predispose the colon to ischaemia more readily than the small bowel:

1. The colon differs from the small bowel in having no villi and therefore no countercurrent mechanism.

2. […]