Intestinal ischemia is caused by the decreased or ceased blood supply to the intestines caused by the disturbance of blood circulation. Acute mesenteric ischemia occurs when the blood supply to the intestines is suddenly interrupted. Chronic ischemia develops when the blood flow in the intestines is constantly disturbed.
- Acute mesenteric ischemia:
- Non-oclusive mesenteric ischemia;
- Embolism of the superior mesenteric artery;
- Thrombosis of the superior mesenteric artery;
- Local segmental ischemia;
- Thrombosis of mesenteric veins;
- Chronic mesenteric ischemia
Acute mesenteric ischemia
Causes and risk factors
About 45-50% of cases are caused by the embolism of the superior mesenteric artery. The thrombi arise from the heart due to the atrial fibrillation, mitral valve disorders, infectious endocarditis, myocardial infarction, heart aneurysm, artificial valves of the heart and many others. Sometimes emboli occur during intraarterial procedures.
Thrombosis of the mesenteric arteries in 25% of cases are the cause of visceral ischemia that develops due to atherosclerotic lesion of the arteries.
Nonoclusive ischemia (20% of cases) is associated with the constriction of the branches of the aorta. This is the result of myocardial infarction, hypotensia (when the systolic arterial pressure is lower than 70 mmHg) and hypovolemia, dehydration and heart failure. Rarely the mesenterial ischemia is the result of the thrombosis of the intestinal veins.
The disease develops in three stages. Primarily occurs ischemia, later – infarction of the bowels and peritonitis.
The leading symptom of the disease is the abdominal pain. The pain is very intense, sharp and occurs acutely, it involves the whole abdomen. The skin is pale, sometimes livid (when the heart failure is present), heart rate is decreased, the blood pressure increases. The abdomen is distended. Affected person experiences nausea, vomiting, diarrhea, rectal bleeding and bloody stools. He/she may scream from pain, although during the palpation of the abdominal wall it appears soft with no guarding or rebound.
Bowel infarction is associated with the reduction of the pain’s intensity. The pain is usually localized in the area of the lesion. The behavior of the person changes – he/she is anxious and loses sleep.
Peritonitis is characterized by the increase of the pain. Sometimes delirium follows. There is no defecation and urine production is decreased or even ceased.
Every affected person should be carefully examined. Blood test, biochemical examination,urine test, abdomianal X-ray, Doppler ultrasound and CT are performed. Angiography is the best option to evaluate the diagnosis.
In most cases urgent surgery is required. The amount of the surgical intervention is defined by the stage of the disease, localization and the length of the lesion, condition of the person. Resection of the part of the bowel may be vital. Percutaneous angioplasty and operative revascularization are the options for the treatment.
Antibiotics, intravenous fluids, electrolyte management, and trombolytic therapy are administered.
[See also: Atherosclerotic Cardiovascular Disease]
Chronic mesenteric ischemia (intestinal angina)
In 80% of cases, chronic visceral ischemia is caused by atherosclerosis, another causes include aortoartheriitis, arterial aneurysms, collagenosis, neoplasms, periarterial and peritoneal fibrosis. All of these diseases lead to the restriction of the blood flow in the supplemental arteries.
Chronic mesenteric ischemia is common among the elderly (60-70 years) and usually affects females.
Affected person experience a dull pain in the area of the navel that spreads to the back. This pain is also called “angina abdominalis”. The abdomen is tender. It occurs 15-30 minutes after the eating and lasts for 1-3 hours. Some persons refuse from eating or eat in small portions (so-called fear of eating). Unintended weight loss, constipation or diarrhea may follow. The sensation of fullness in epigasric region, abdominal distension, flatulation are also present.
Angiography and CT are performed to identify the cause of the disorder.
The treatment of chronic mesenteric ischemia includes:
- Dietary restrictions;
- Vasodilatators: beta-blockers, calcium channel blockers, nitroglycerin;
- Symptomatic therapy;
- Hypolipidemic drugs.
In some cases, surgery is required. Stent implantation, resection of the artery, thrombendartherectomy, grafts implication may be performed. The aim of the surgery is to eliminate the cause of the restriction.