Mesenteric Vascular Occlusion, Acute

• • Severe, diffuse abdominal pain

  • Gross or occult intestinal bleeding

  • Minimal physical findings

  • Radiographic findings of vascular occlusion

  • Operative findings of ischemic bowel

Epidemiology

• • Predominantly a disease of the elderly

  • Tissue injury is caused by both ischemia itself as well as reperfusion

  • Mesenteric arterial emboli (50%): Commonly originate from mural thrombus in an infarcted LV or clot in a fibrillating LA

  • Thrombosis of a mesenteric artery (25%): The end result of atherosclerotic stenosis; often a history of intestinal angina

  • Rare causes of acute arterial occlusion include:

  • -Dissecting aortic aneurysm

    -Connective tissue disorders

    -Cocaine ingestion

  • Thrombosis of mesenteric veins (5%): Associated with portal hypertension, abdominal sepsis, hypercoagulable states, or trauma

  • Nonocclusive mesenteric ischemia accounts for the remaining 20% of cases of mesenteric ischemia

Symptoms and Signs

• • Severe, poorly localized abdominal pain that is often out of proportion to physical findings

  • Nausea and vomiting

  • Diarrhea

  • Shock

  • GI bleeding

  • Abdominal distention

  • Abdominal tenderness

  • Peritonitis

Laboratory Findings

• • Leukocytosis

  • Serum amylase is elevated

  • Significant base deficits

  • Increased serum phosphate

  • Anemia

  • Increased serum lactate

  • Antithrombin III deficiency and other abnormalities of coagulation should be sought in cases of venous thrombosis

Imaging Findings

• • Abdominal x-ray:

  • -Nonspecific

    -Absence of intestinal gas

    -Diffuse distention with air-fluid levels

  • Specific findings occur late

  • -Intramural gas

    -Gas in the portal venous system

  • GI contrast radiography: Thumbprinting and disordered motility

  • CT scan

  • -Diffuse distention with air-fluid levels

    -Intestinal wall thickening

    -Intramural gas

    -Gas in the portal venous system

  • Mesenteric arteriography: The gold standard showing disrupted intestinal arterial blood flow or absence of a venous phase

• • Survival depends on diagnosis and operative treatment within 12 hours after onset of symptoms

  • In the early stages, there is a striking paucity of abdominal findings

  • Pain out of proportion to the objective findings is a hallmark of mesenteric vascular occlusion

  • Later in the disease course, abdominal distention and tenderness occur

  • Shock and generalized peritonitis eventually develop

  • Causes of hypercoagulability should be sought postoperatively in cases of venous thrombosis

Rule Out

• • Acute pancreatitis

  • Strangulation obstruction

  • Nonocclusive intestinal ischemia

• • CBC

  • Serum electrolytes

  • Serum amylase

  • Serum lactate

  • ABG measurements

  • Abdominal x-ray

  • CT scan

  • Arteriography

  • Hypercoagulable studies (venous thrombosis)

When to Admit

• • All cases

Surgery

• • Resection of all involved gut; revascularization of proximal stenosis indicated to salvage viable bowel; thrombectomy usually unsuccessful

  • Role of angioplasty and stenting combined with operation depends upon the precise vascular lesions

Indications

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