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:''This article concerns ischemia of the small bowel. See ischemic colitis for ischemia of the large bowel'' Mesenteric ischemia, also known as mesenteric vascular disease, is a medical condition in which injury of the small intestine occurs due to not enough blood supply. It can come on suddenly, known as acute mesenteric ischemia, or gradually, known as chronic mesenteric ischemia.〔 Acute disease often presents with sudden severe pain. Symptoms may come on more slowly in those with acute on chronic disease.〔 Signs and symptoms of chronic disease include abdominal pain after eating, unintentional weight loss, vomiting, and being afraid of eating.〔〔 Risk factors include atrial fibrillation, heart failure, chronic renal failure, being prone to forming blood clots, and previous myocardial infarction.〔 There are four mechanisms by which poor blood flow occurs: a blood clot from elsewhere getting lodged in an artery, a new blood clot forming in an artery, a blood clot forming in the mesenteric vein, and insufficient blood flow due to low blood pressure or spasms of arteries.〔 Chronic disease is a risk factor for acute disease. The best method of diagnosis is angiography, with computer tomography (CT) being used when that is not available.〔 Treatment of acute ischemia may include stenting or medications to break down the clot provided at the site of obstruction by interventional radiology.〔 Open surgery may also be used to remove or bypass the obstruction and may be required to remove any intestines that may have died.〔 If not rapidly treated outcomes are often poor.〔 Among those affected even with treatment the risk of death is 70% to 90%. In those with chronic disease bypass surgery is the treatment of choice.〔 Those who have thrombosis of the vein may be treated with anticoagulation such as heparin and warfarin, with surgery used if they do not improve.〔 Acute mesenteric ischemia affects about five per hundred thousand people per year in the developed world. Chronic mesenteric ischemia affects about one per hundred thousand people. Most people affected are over 60 years old.〔 Rates are about equal in males and females of the same age.〔 Mesenteric ischemia was first described in 1895.〔 ==Signs and symptoms== Three progressive phases of ischemic colitis have been described: *A ''hyper active'' stage occurs first, in which the primary symptoms are severe abdominal pain and the passage of bloody stools. Many patients get better and do not progress beyond this phase. *A ''paralytic'' phase can follow if ischemia continues; in this phase, the abdominal pain becomes more widespread, the belly becomes more tender to the touch, and bowel motility decreases, resulting in abdominal bloating, no further bloody stools, and absent bowel sounds on exam. *Finally, a ''shock'' phase can develop as fluids start to leak through the damaged colon lining. This can result in shock and metabolic acidosis with dehydration, low blood pressure, rapid heart rate, and confusion. Patients who progress to this phase are often critically ill and require intensive care. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「mesenteric ischemia」の詳細全文を読む スポンサード リンク
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