Ischaemic Colitis

Condition

Caused by thrombosis in an atherosclerotic superior mesenteric artery, or from emboli (e.g. from AF) — necrosis of the bowel soon follows. Inferior mesenteric artery ischaemia can also develop, which is less severe and has better survival.

Demographics: elderly patients; cardiovascular disease risk factors; atrial fibrillation.

Murtagh’s triad: anxiety and prostration + intense central abdominal pain + profuse vomiting ± bloody diarrhoea suggests mesenteric artery occlusion.

History

Abdominal pain gradually becoming severe; patients may develop a “fear of eating” (severe pain 15–30 minutes after food); profuse vomiting; watery diarrhoea, which later becomes bloody in only about a third of cases; confusion.

Examination

Tenderness, rigidity; absent bowel sounds (a late sign); shock; tachycardia.

Investigations

Not particularly useful in the outpatient setting. CRP may be raised. X-ray shows “thumb-printing” from bowel wall oedema. CT angiography (CTA) is the preferred initial imaging investigation for suspected acute mesenteric ischaemia. Catheter angiography is reserved for a high suspicion of acute mesenteric ischaemia with a negative CTA, or for suspected non-occlusive mesenteric ischaemia. In patients with peritonitis, the diagnosis is made by abdominal exploration.

Management

Early surgery is necessary for survival (within hours). May require resection of large segments of necrotic bowel.