Acute ischaemia: Mesenteric Flashcards Preview

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Flashcards in Acute ischaemia: Mesenteric Deck (17)
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Define acute mesenteric ischaemia

Sudden inadequate blood flow through the mesenteric vessels ➔ ischaemia and gangrene of the bowel wall.


Which age group does acute mesenteric ischaemia tend to occur in?

Aged over 50


Categorise the four primary causes of acute mesenteric ischaemia

  • Non-occlusive mesenteric ischaemia (NOMI) - 20%
  • Acute mesenteric arterial embolism (AMAE) - 50%
  • Acute mesenteric arterial thrombosis (AMAT) - 25%
  • Mesenteric venous thrombosis (MVT) - <10%


Name two secondary causes of acute mesenteric ischaemia

  • Mechanical obstruction
  • Tumour compression
  • Post-angiograph thrombosis


Give two causes of acute mesenteric arterial embolism

  • Cardiac emboli: post-MI; AF; mitral stenosis; endocarditis
  • Ruptured proximal atheromatous plaque
  • Dislodged atheromatous plaque (iatrogenic)


Which vessel is most commonly involved in acute mesenteric arterial embolism?

Superior mesenteric artery (SMA)


Name three causes of acute mesenteric arterial thrombosis

  • Atherosclerosis
  • Aortic aneurysm
  • Aortic dissection
  • Arteritis
  • Decreased cardiac output
  • Dehydration


How does acute mesenteric ischaemia differ between embolic and thrombotic causes?

Embolic events tend to occur in arterial branches ➔ limited ischaemia

Thrombosis typically occurs at the vessel origin ➔ extensive ischaemia


Name two causes of non-occlusive mesenteric ischaemia

  • Hypotension (CHF, MI, sepsis etc.)
  • Vasopressor drugs
  • Ergotamines (migraine Tx)
  • Cocaine
  • Digitalis (foxglove)


Name two causes of mesenteric venous thrombosis

  • Hypercoagulability
  • Tumour: venous compression; hypercoagulability
  • Infection
  • Portal hypertension due to cirrhosis
  • Venous trauma


Describe the presentation of acute mesenteric ischaemia

  • Moderate-severe colicky or constant diffuse pain
    • Disproportionate to physical examination findings
    • Especially post-prandial
  • NaV (75%)
  • Anorexia - avoidance of postprandial pain
  • Obstipation (complete severe constipation)
  • Early: minimal or no tenderness, no signs of peritonitis
  • Later: peritonism, may be a palpable mass


What additional clinical features develop as the bowel becomes gangrenous?

  • Rectal bleeding
  • Sepsis


Name three potential investigations for acute mesenteric ischaemia

  • CT angiography
  • FBC and ABG: sepsis; metabolic acidosis
  • Clotting
  • G+S
  • AXR: exclude other causes
  • Erect CXR: assess bowel perforation
  • Multidetector CT: if SMA occlusion suspected
  • ECG: AF or MI
  • Echo: embolic source; valvular pathology


Name three differential diagnoses for acute mesenteric ischaemia

  • Acute abdomen (cholecystitis, appendicitis, pancreatitis etc.)
  • Abdominal aortic aneurysm
  • Ectopic pregnancy
  • MI
  • Testicular torsion
  • Sepsis: multiorgan failure


Outline the initial management of acute mesenteric ischaemia

  • Fluid and oxygen resuscitation
  • Senior support and early ITU input
  • NG tube
  • Broad spectrum IV antibiotics
  • IV heparin


Outline the definitive management of acute mesenteric ischaemia

  • Laparotomy if overt peritonitis
  • Revascularisation if possible
    • Otherwise, resect all non-viable regions
  • Preserve all viable bowel


Describe the prognosis of acute mesenteric ischaemia

Give two complications

Poor prognosis

  • Missed diagnosis: 90% mortality
  • Treated: 50-80% mortality
  • Extensive bowel surgery has potential of lifetime disability

Complications: bowel necrosis; perforation; short gut syndrome (malabsorption)