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Related Subjects: |Metabolic acidosis |Aspirin or Salicylates toxicity |Ethylene glycol toxicity |Renal Tubular Acidosis |Lactic acidosis

Ischaemic colitis usually resolves but carefully observe as can progress to gangrene and peritonitis or stricture formation. The condition is commonly seen in older patients in their sixties to seventies.

About

• Ischaemia of the colon due to impaired blood supply
• Inflammation and superficial injury to full thickness necrosis.
• Colon supplied by superior (SMA) and inferior mesenteric arteries (IMA)
• Watershed area is splenic flexure

Aetiology

• Thrombosis/Embolism/Vasculitis/Spasm/Low flow
• Atrial fibrillation, Atherosclerosis e.g. atheroma in IMA
• Mucosal ischaemia, inflamed, necrotic and ulceration and perforation
• Splenic flexure commonly affected at the watershed between SMA and IMA
• Complication of aortic aneurysm surgery.

Bloody bowel movements, abdominal pain, and raised WCC and lactate in an older patient

Clinical

• Crampy abdominal pain, vomiting, diarrhoea (may be bloody)
• Abdominal distension, fever, tachycardia
• Gut claudication in more subacute or chronic cases
• Recurrent gastroenteritis picture in more subacute or chronic cases
• Localised peritonism on exam

Complications

• Sepsis, Peritonism, Perforation, Toxic megacolon
• Late: Stricture formation usually at splenic flexure of the colon

Investigations

• FBC: High WCC High CRP High Lactate, LDH, CK may be seen
• ABG : metabolic acidosis + lactate
• AXR : a nonspecific gas pattern or ileus. As the disease progresses, submucosal haemorrhage or oedema can result in focal mural thickening, often described as “thumbprinting." Perforation and pneumatosis are consistent with severe injury to the colon.
• Stool culture if diarrhoea and diagnostic uncertainty
• Barium enema in subacute presentations - thumb printing due to submucosal swelling
• CXR - air under diaphragm if perforation
• CT scan may show thickened colonic wall, intramural air. Pneumatosis or portal venous gas, when seen, are a late finding and suggest bowel infarction
• Colonoscopy without bowel preparation is the diagnostic test of choice to evaluate the degree of ischaemia. Colonoscopy remains the most sensitive and specific study available for the diagnosis of ischaemic colitis because it allows for detection of mucosal changes by directly visualizing the mucosa.

Management

• Fluid and general resuscitation ABC. Consider starting UFH.
• Broad Spectrum Antibiotics. NG tube and suction if nil orally
• Many settle conservatively
• Surgery is laparotomy and resection and exteriorisation of affected bowel ends.
• Primary anastomosis is contraindicated. Mortality is high.