Sudden disruption of blood flow to the intestines primarily involving the mesenteric vessels.

Caused by a blood clot (thrombus) or a blocked artery (embolism).

Results in intestinal damage, tissue necrosis, and life-threatening complications due to inadequate blood supply.

Urgent medical intervention is required to prevent serious complications and improve outcomes.

Arterial Embolism (50%), Arterial Thrombosis (25%), Non-Occlusive Disease (20%), Venous Thrombosis (<10%).

Cardiac conditions such as atrial fibrillation, post-MI mural thrombosis, and prosthetic heart valves. Abdominal/thoracic aneurysms.

Atherosclerosis is the primary risk factor.

Low flow states like recent cardiac surgery, cardiac or renal failure. Hypovolaemic or cardiogenic shock.

Hypercoagulable states (more common in younger patients), malignancy, inflammatory conditions (e.g. pancreatitis, diverticulitis), trauma.

• Advanced age
• Cardiovascular disease (e.g. atherosclerosis)
• Atrial fibrillation
• Hypercoagulable states
• History of thrombosis or blood clotting disorders
• Recent abdominal surgery
• Aortic dissection or aneurysm
• Decreased cardiac output (e.g. myocardial infarction, heart failure).

• Atherosclerosis-promoting factors:
– Smoking
– Hypertension
– Diabetes mellitus
– Hyperlipidaemia.

• Sudden reduction in blood flow to the intestines leading to tissue hypoxia and ischemia.

• Blockage of mesenteric vessels (arterial or venous) reduces oxygen and nutrient delivery to intestinal tissues.

• Tissue damage
• Potential for tissue necrosis if blood flow is not promptly restored.

• To prevent intestinal damage, tissue death, and life-threatening complications due to insufficient blood supply.

• Extent of blood flow disruption
• Duration of the ischemic event.

Differential Diagnoses:
• Abdominal aortic aneurysm
• Appendicitis
• Biliary disease
• Chronic mesenteric ischaemia
• Cholecystitis
• Diverticulitis
• Ectopic pregnancy
• Gastrointestinal perforation
• Intestinal obstruction
• Myocardial infarction
• Pancreatitis
• Pneumonia or pneumothorax
• Testicular torsion

Chronic Ischaemia Differential:
• Acute mesenteric ischaemia
• Dyspepsia
• Gastric cancer
• Chronic pancreatitis
• Chronic pyelonephritis

Approximately 1 in 100,000 population per year.

More common in individuals over 50 years of age, especially those over 60.

It accounts for 0.09-0.2% of all hospital admissions.

Very low incidence (<1 in 1,000 hospital admissions for abdominal pain), predominantly affecting females aged 50-70, often coexisting with other atherosclerotic conditions.

– Severe abdominal pain that is disproportionate to physical findings
– Sudden onset of pain
– Tenderness on examination
– Nausea and vomiting
– Signs of systemic illness: tachycardia, hypotension

Pain is typically acute, severe, and generalized, often described as diffuse and constant, with nausea and vomiting in about 75% of cases.

– Moderate-to-severe colicky or constant pain, poorly localized
– Early stages: minimal or no tenderness, no signs of peritonitis
– Later stages: peritonism with rebound guarding and tenderness
– May reveal underlying conditions such as atrial fibrillation

– Moderate-to-severe colicky or constant pain
– History of weight loss, postprandial pain (intestinal angina), and fear of eating
– Often associated with cardiovascular disease

– Vague abdominal tenderness
– Abdominal bruit
– Signs of generalized cardiovascular disease
– Nonspecific symptoms: nausea, vomiting, bowel irregularity

• Arterial Blood Gas (ABG): Raised lactate and metabolic acidosis.
• Full Blood Count (FBC): Raised haemoglobin (Hb) due to plasma loss and increased white cell count (WCC).
• Urea and Electrolytes (U&Es): Monitor kidney function, especially when using IV contrast for imaging.
• Liver Function Tests (LFTs): Raised AST and ALT indicate a poor prognosis.
• Clotting profile: Important for patients on anticoagulants.
• Amylase: To exclude acute pancreatitis, which may also be elevated in mesenteric ischaemia.
• Group and Screen (G&S): Prepare for potential blood transfusion during surgery.

• CT Angiography: Gold standard for diagnosis, offering high accuracy in detecting mesenteric ischaemia.
• Abdominal X-ray (AXR): May reveal small bowel obstruction, ileus, or thickened bowel walls in later stages.
• Erect Chest X-ray (CXR): Utilised when bowel perforation is suspected.
• Ultrasound and MRI: Useful in specific cases, particularly to avoid radiation exposure.
• ECG: Identifies atrial fibrillation or signs of cardiac-related emboli.
• Echocardiogram: Assesses for embolic sources or valvular pathology.
• Intraoperative fluorescein: Highlights ischaemic bowel regions during surgery.

• Early diagnosis using CT Angiography is essential to lower mortality.
• While there are no specific lab tests, raised WCC and metabolic acidosis are common indicators.
• Imaging, particularly CT Angiography, may show bowel abnormalities, unusual gas patterns, and signs of infarction.
• Ultrasound, MRI, ECG, and echocardiogram provide additional diagnostic insights in specific cases.

• FBC, LFTs, and U&Es: Assess for malnutrition or dehydration.
• CXR: Exclude pneumonia as a differential diagnosis.
• Arteriography: Gold standard for identifying arterial blockages or stenosis.
• Mesenteric duplex ultrasonography: Non-invasive assessment of arterial blood flow, though less effective in obese patients.
• Cardiac scanning: To exclude comorbid cardiac conditions.

Treatment Goals: Restore blood flow and address underlying causes
Initial Medical Interventions:
• Resuscitation with IV fluids and oxygen
• Nasogastric tube placement
• Intravenous broad-spectrum antibiotics
• Intravenous unfractionated heparin (if not contraindicated)

Surgical Interventions:
• Prompt laparotomy for overt peritonitis
• Surgical goals: Re-establish blood supply, resect non-viable bowel, preserve viable bowel
Endovascular Procedures: Considered for partial arterial occlusion

Long-Term Management: Lifelong anticoagulant or antiplatelet therapy may be required
Outcomes: High mortality rate (50-80%); survivors may develop short gut syndrome

Emergency Management:
• IV fluids, broad-spectrum antibiotics, and LMWH
• Urgent exploratory laparotomy to remove necrotic bowel
Complications: Life-threatening complications include septic peritonitis, multi-organ failure, and potential short gut syndrome

Conservative Management: Smoking cessation and antiplatelet therapy
Prognosis: Five-year mortality of 40%, often due to myocardial infarction or cardiovascular death

Indication: Open or endovascular revascularisation is recommended
Prognosis: Untreated symptomatic CMI is associated with a five-year mortality rate approaching 100%

Nutrition Assessment: Important due to frequent malnourishment; may require total parenteral nutrition pre- and postoperatively

Considerations: Anatomy and the pre-operative condition of the patient

Complication: Renal failure is a common postoperative complication

• Duration of ischemia
• Extent of intestinal damage
• Presence of complications (e.g. bowel perforation, peritonitis)
• Timeliness of intervention.

• Missed diagnosis: Mortality rate can reach 90%
• Even with treatment, mortality remains 50-90%.

• Significant disability post-surgery.

• Poor quality of life
• Fear of abdominal pain leading to significant weight loss
• Malnutrition causing metabolic and endocrine issues like osteoporosis and easy bruising.

• Bowel infarction: Tissue death due to inadequate blood supply
• Peritonitis: Inflammation of the abdominal lining due to bacterial translocation
• Sepsis: Systemic infection from bacterial spread
• Bowel perforation: Rupture of the intestinal wall
• Multiple organ failure: Progressive dysfunction of multiple organ systems.

• Significantly increase morbidity and mortality if not promptly managed.