Mechanisms of blood flow disorders
The intestine is fed by three main arteries that arise from the aorta, the main one being the superior mesenteric artery. With an embolism, a clot from the heart blocks it suddenly, and symptoms appear instantly. With thrombosis, a clot forms on a plaque, and before the disaster, a person often suffers from pain after eating and weight loss for years. Venous thrombosis develops more slowly, over days, and is more often associated with coagulation disorders. A separate option is non-occlusive ischemia during shock, when the vessels spasm, remaining passable.
- Embolism of the superior mesenteric artery
- Arterial thrombosis on an atherosclerotic plaque
- Mesenteric vein thrombosis
- Non-occlusive ischemia in shock and dehydration
- Aortic dissection with transition to mesenteric vessels
- Compression of blood vessels by tumor or adhesions
Causes and risk factors
The main source of emboli is the heart: atrial fibrillation without anticoagulants, a thrombus in the left ventricle after a heart attack, prosthetic valves. Arterial thrombosis develops against the background of widespread atherosclerosis, in which there are already signs of chronic intestinal ischemia. Venous thrombosis is associated with hereditary and acquired thrombophilias, liver cirrhosis and portal hypertension, cancer, inflammation in the abdominal cavity, recent operations and taking hormonal drugs.
- Atrial fibrillation
- Previous myocardial infarction
- Common atherosclerosis
- Thrombophilia
- Liver cirrhosis and portal hypertension
- Malignant tumors
- Dehydration, shock, heart failure
Symptoms and stages
In the first hours, the pain in the abdomen is very intense, widespread, and cannot be relieved by conventional means, while the abdomen remains soft and there is no muscle tension - this is a discrepancy and should alert you. Vomiting and the urge to defecate are common. Then comes a deceptive period of relative improvement: the nerve endings in the intestinal wall die and the pain subsides. Finally, peritonitis develops: the abdomen swells, becomes hard and sharply painful, and signs of severe intoxication and shock appear.
- Ischemia stage: severe pain with soft abdomen
- Vomiting, loose stools, sometimes with blood
- Stage of imaginary well-being: pain decreases
- Stage of peritonitis: bloating, hard abdomen
- No passing of gas or stool
- Drop in blood pressure, rapid pulse, confusion
Diagnostics
The main method is computed tomography of the abdominal cavity with intravenous contrast in the arterial and venous phases: it shows the location of the blockage, the condition of the intestinal wall and signs of its necrosis. Doppler ultrasound can detect disturbances in blood flow in large vessels, but with intestinal bloating, the information content decreases. The tests are nonspecific: high leukocytosis and increasing lactate indicate severity, but normal readings in the first hours do not exclude the diagnosis. Plain radiography helps to exclude other catastrophes in the abdomen.
- CT angiography of the abdominal cavity - the method of choice
- Ultrasound of abdominal vessels with Doppler
- Complete blood count and leukocytosis
- Lactate and acid-base status
- Coagulogram and D-dimer
- Plain radiography of the abdominal cavity
- ECG to find the source of the embolus
Treatment and prevention
Treatment is carried out only in a hospital. Immediately begin administering anticoagulants, replenish fluid volume, and maintain blood circulation. Further tactics depend on the mechanism: in case of arterial blockage, a blood clot is removed, bypass surgery or intravascular intervention; in case of intestinal necrosis, its resection is performed, sometimes with a second revision every other day. Venous thrombosis without signs of necrosis can be treated conservatively with anticoagulants. After recovery, be sure to look for and eliminate the cause, otherwise the risk of recurrence remains high.
- Immediate hospitalization in a surgical hospital
- Anticoagulant therapy from the time of diagnosis
- Removal of a blood clot or bypass of a vessel
- Resection of dead intestine
- Intravascular methods of restoring blood flow
- Intensive therapy and metabolic correction
- Long-term anticoagulant prophylaxis and treatment of arrhythmia
