Ischaemic Colitis is the inflammation and injury of the colon due to insufficient blood supply primarily affecting the transverse and descending segments, especially near the splenic flexure.

The condition involves the marginal branches of the middle colic (from the superior mesenteric artery) and left colic (from the inferior mesenteric artery) arteries.

‘Watershed’ areas like the splenic flexure, where the blood supply from the superior and inferior mesenteric arteries overlaps, are particularly vulnerable.

Blood flow can be impaired by:

– Colonic distension (due to obstruction or pseudo-obstruction)

– Venous occlusion

An x-ray may reveal ‘thumbprinting’ due to mucosal oedema or haemorrhage.

Management is generally supportive, but surgery may be required if complications such as generalized peritonitis, perforation, or ongoing haemorrhage occur.

Causes of Ischaemic Colitis:

• Acute Arterial Occlusion: Sudden blockage of colonic arteries

• Chronic Mesenteric Ischaemia: Gradual reduction in blood flow to the colon

• Vasculitis: Inflammation of blood vessels affecting blood supply

• Hypoperfusion during Systemic Hypotension: Reduced blood flow due to low blood pressure

• Vasoconstrictive Medications: Drugs that cause blood vessel constriction

• Blood Flow Impairment: Colonic distension and venous occlusion

Predisposing Factors:

• Age: Increasing age

• Atrial Fibrillation: Especially for mesenteric ischaemia

• Causes of Emboli: Endocarditis, malignancy

• Cardiovascular Disease Risk Factors: Smoking, hypertension, diabetes

• Cocaine Use: Seen in younger patients with ischaemic colitis

General Risk Factors:
• Age: More common in older individuals
• Cardiovascular Disease: Underlying heart conditions
• Hypotension: Low blood pressure
• Vasoconstrictive Medications: Drugs causing blood vessel constriction

Lifestyle Risk Factors:
• Smoking: Tobacco use
• Long-Distance Running: Intense physical activity

Medical History Factors:
• Abdominal Surgery: History of previous surgeries
• Thrombosis: Blood clot formation
• Embolism: Movement of clots causing blockages
• Decreased Cardiac Output or Arrhythmias: Heart function abnormalities

Contributing Conditions:
• Shock: Conditions like sepsis, hemorrhage, or low blood volume
• Trauma: Physical injuries
• Strangulated Hernia or Volvulus: Intestinal obstructions
• Vasculitis: Inflammation of blood vessels (e.g., systemic lupus erythematosus, polyarteritis nodosa, sickle cell disease)

Coagulation Disorders:
• Blood Clotting Disorders: Protein C and S deficiency, Activated protein C resistance, Antithrombin III deficiency

Medical Procedures:
• Colonoscopy or Barium Enema: Medical interventions

Other Causes/Risk Factors:
• Idiopathic: Unknown causes
• Drugs: Digitalis, cocaine, vasopressin, psychotropic agents, immunosuppressive agents
• Surgery: Cardiac bypass, aortic dissection

• Reduced blood flow to the colon leads to tissue hypoxia and ischaemia
• Results in mucosal and submucosal haemorrhage, inflammation, and ulceration

• Infectious colitis

• Inflammatory bowel disease (Crohn’s disease, Ulcerative colitis)

• Diverticulitis

• Colorectal carcinoma

• Ischaemic colitis accounts for 50-60% of all cases of colonic ischaemia
• More common in individuals over 60 years old

Abdominal pain, often sudden and severe, particularly in the left iliac fossa; rectal bleeding; diarrhea; and nausea.

Symptoms typically have a rapid onset (within hours) and worsen with systemic instability. This differentiates it from inflammatory or infective colitis.

Marked tenderness in the left iliac fossa; peritonitis may indicate full thickness ischemia or perforation.

Nonspecific symptoms resembling ‘acute abdomen’, including acute-onset abdominal pain, nausea, vomiting, and later symptoms like loose stools with dark blood.

Potential associations with contraceptive use, cocaine or methamphetamine abuse, pseudoephedrine use, sickle cell disease, and inherited coagulopathies.

Abdominal pain disproportionate to physical findings, rectal bleeding, diarrhea, fever, and elevated white blood cell count with lactic acidosis in blood tests.

Blood tests are used to assess inflammation and rule out other potential causes. The presence of metabolic acidosis may also serve as a diagnostic clue.

Colonoscopy may show:
– Blue, swollen mucosa
– Lack of contact bleeding
– Sparing of the rectum

A plain abdominal X-ray may show:
– Abnormal segment outlined with gas
– Nonspecific findings in the first 12-18 hours after onset

Early phase findings include a “thumbprinting” appearance, which may persist for several days.

Subsequent changes can include:
– Mucosal return to normal or progression to ulceration
– Appearance resembling segmental ulcerative colitis or Crohn’s disease

Outcomes may include:
– Spontaneous resolution
– Progression to intestinal narrowing
– Sacculation of the antimesenteric border

Additional imaging modalities include:
– CT Scan (preferred for diagnosing bowel ischaemia)
– MRI Scan
– Angiography

Nonspecific findings are common in the first 12-18 hours after onset, making early diagnosis challenging.

• Bowel rest
• Intravenous fluids
• Pain management

• Transient cases: Resolve with alleviation of hypoperfusion and broad-spectrum antibiotics
• Severe cases: Require hospitalization and may need surgical intervention if complications arise

Surgical care is indicated when there is:
– No improvement within 24-48 hours
– Signs of severe disease such as increasing abdominal tenderness, fever, or bleeding
– Evidence of bowel infarction or perforation, warranting urgent laparotomy

• Mild cases: Typically resolve without significant issues
• Severe cases: Risk of bowel necrosis, perforation, sepsis, and higher mortality

Prognosis is influenced by:
– Location and extent of the disease
– Coexisting conditions
– The necessity for emergency surgery

The mortality rate is approximately 22%.

• Generally good with appropriate management
• Severe cases with complications have a higher mortality rate

• Colonic necrosis
• Perforation
• Stricture formation
• Persistent bleeding