Occlusion of the inferior mesenteric artery leads to ischaemia of the left colon particularly when blood flow in the superior mesentric artery is also reduced.
The patient presents with colicky lower abdominal pain, nausea, vomitting and diarrhoea with the passage of blood and mucus. On examination there is tenderness and guarding on the left side of the abdomen and particularly in the left illiac fossa. Bowel sounds are usually present. In some patients the episode is transient; in others there may be persistent bleeding and pain suggesting progression to stricture formation. About 10% of patients progress to shock with generalised abdominal pain indicative of peritonitis secondary to gangrene.
Investigation
Several investigations are helpful. Leucocytosis is common. Sigmoidoscopy usually shows abnormal rectal mucosa but blood may be seen descending from above. A plain radiograph of the abdomen shows 'thumb printing' at the splenic flexure and descending colon which are indentations of the bowel wall from sub mucosal haemorrhage and oedema.
A double-contrast barium enema usually demonstrates the characteristic distribution of maximal involvement at the splenic flexure and sigmoid colon. The mucosal features are 'thumb printing' and ulceration. Stricture develops in up to 50% of patients and is demonstrated by a barium enema repeated after 2-3 weeks.
Management
Most cases resolve with conservative management. Surgery is necessary when there are sign's of peritonitis or when symptomatic stricture develops.
The patient presents with colicky lower abdominal pain, nausea, vomitting and diarrhoea with the passage of blood and mucus. On examination there is tenderness and guarding on the left side of the abdomen and particularly in the left illiac fossa. Bowel sounds are usually present. In some patients the episode is transient; in others there may be persistent bleeding and pain suggesting progression to stricture formation. About 10% of patients progress to shock with generalised abdominal pain indicative of peritonitis secondary to gangrene.
Investigation
Several investigations are helpful. Leucocytosis is common. Sigmoidoscopy usually shows abnormal rectal mucosa but blood may be seen descending from above. A plain radiograph of the abdomen shows 'thumb printing' at the splenic flexure and descending colon which are indentations of the bowel wall from sub mucosal haemorrhage and oedema.
A double-contrast barium enema usually demonstrates the characteristic distribution of maximal involvement at the splenic flexure and sigmoid colon. The mucosal features are 'thumb printing' and ulceration. Stricture develops in up to 50% of patients and is demonstrated by a barium enema repeated after 2-3 weeks.
Management
Most cases resolve with conservative management. Surgery is necessary when there are sign's of peritonitis or when symptomatic stricture develops.
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