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Mesenteric Ischemia

Mesenteric ischemia is classified as acute mesenteric ischemia (AMI) chronic mesenteric ischemia (CMI). AMI is subdivided into occlusive and nonocclusive mesenteric ischemia. Occlusive mesenteric ischemia results from either thrombotic or embolic arterial or Approximately 80% of cases of AMI are occlusive in etiology, with arterial emboli or thromboses in 65% of

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Mesenteric Arterial Embolism

The median age of patients presenting with mesenteric arterial embolism is 70 years. The overwhelming majority of emboli lodge in the superior mesenteric artery (SMA).

Emboli originating in the left atrium or ventricle are the most common cause of SMA embolism. Risk factors include advanced age, coronary artery disease, cardiac valvular disease, history of dysrhythmias, atrial fibrillation, post-myocardial infarction mural thrombi, history of thromboembolic events, aortic surgery, aortography, coronary angiography, and aortic dissection.

The disorder usually presents as sudden onset of severe poorly localized periumbilical pain, associated with nausea, vomiting, and frequent bowel movements. Pain is usually out of proportion to the physical findings may be the only presenting symptom.

The abdomen may be soft with only mild tenderness. Absent bowel sounds, abdominal distension or guarding are indicative of severe disease.

Blood in the rectum is present in 16% of patients, and occult blood is present in 25% of patients. Peritoneal signs develop when the ischemic process becomes transmural.

Mesenteric Arterial Thrombosis

Thrombosis usually occurs in the area of atherosclerotic narrowing in the proximal SMA. The proximal jejunum through the distal transverse colon becomes ischemic.

SMA thrombosis usually occurs in patients with chronic, severe, visceral atherosclerosis; a history of abdominal pain after meals is present in 20-50% of patients. Patients are often elderly with coronary artery disease, severe peripheral vascular disease, or hypertension.

SMA thrombosis presents with gradual onset of abdominal pain and distension. A history of postprandial abdominal pain and weight loss is present in half of cases. Pain is usually out of proportion to the physical findings, and nausea and vomiting are common.

Signs of peripheral vascular disease, such as carotid, femoral or abdominal bruits, or decreased peripheral pulses are frequent. Abdominal distension, absent bowel sounds, guarding, rebound and localized tenderness, and rigidity indicate

Diagnostic Evaluation of Acute Mesenteric Ischemia

Leukocyte count is elevated in most cases of mesenteric ischemia. Leukocyte counts of 10-15,000/mm3 are present in 25% of cases, 15-30,000 in 50%, and 25% of patients have values >30,000.

In patients with SMA emboli, 42% have a metabolic acidosis. The serum amylase is elevated in half of Mesenteric Ischemia, Infarction, bowel ischemia, bowel infarction patients up to twice the normal values.

Emergency Treatment

Stabilization and Initial Management2. Patients without peritoneal signs with minor emboli, who achieve pain relief with vasodilator infusion, may be managed nonoperatively with repeated angiograms. Postoperative anticoagulation is recommended for all patients.

Acute Mesenteric Infarction With Thrombosis

Acute mesenteric ischemia secondary to thrombosis is treated initially with a papaverine infusion started at angiography. Patients without peritoneal signs with minor thrombi may mesenteric ischemia, infarction, bowel ischemia, bowel infarction be treated with papaverine only. Patients with major thrombi with good collateral vasculature, without peritoneal signs, may be observed in the hospital without a papaverine infusion. Patients with peritoneal signs and documented thrombosis require mesenteric ischemia, infarction, bowel ischemia, bowel infarction laparotomy.

Endarterectomy, Mesenteric Ischemia, Infarction, bowel ischemia, bowel infarction thrombectomy and mesenteric revascularization with aortomesenteric bypass grafting are the most common methods of treatment. '