Why does the intestine lack blood?
The large intestine is supplied with blood from the branches of the mesenteric arteries, and some of its sections are located on the border of two basins, where the blood flow is especially vulnerable. If the pressure drops, the heart works weaker, or the vessel is narrowed by an atherosclerotic plaque, these areas are the first to suffer. The mucous membrane, the most oxygen-demanding layer, is primarily affected. With a short-term decrease in blood flow, the changes are reversible; with a long-term decrease, the damage covers the entire thickness of the wall, which threatens perforation and peritonitis.
- Border zones of blood supply are most vulnerable
- The mucous membrane suffers before other layers
- Short-term ischemia is reversible
- Prolonged ischemia leads to necrosis and perforation
- Thrombus and embolus more often cause ischemia of the small intestine
Causes and risk factors
Most often, there is no specific blockage of the vessel: blood flow is reduced due to general reasons - a drop in pressure due to dehydration, blood loss, sepsis, heart failure or severe arrhythmia. Atherosclerosis and diabetes play a role. Triggers may include surgery on the aorta and heart, hemodialysis, intense marathon running, taking certain medications, including diuretics, vasoconstrictors, hormonal contraceptives, as well as constipation with severe straining.
- Age over 60 years
- Atherosclerosis, hypertension, diabetes mellitus
- Heart failure and arrhythmia
- Dehydration and pressure drop
- Surgeries on the aorta and heart
- Some medications
- Conditions with increased blood clotting
Symptoms
The disease begins suddenly with cramping pain, often in the left half of the abdomen, less often around the navel. Almost immediately there is a persistent urge to defecate. During the first 24 hours, blood is added to the stool - usually small, dark or bright red, mixed with stool or mucus. In mild cases, the abdomen is soft and painful when pressed in the projection of the affected area. Massive bleeding, as a rule, does not occur; if there is a lot of blood, they look for another source.
- Sudden cramping pain in the abdomen, usually on the left
- Urgent urge to defecate
- Blood in the stool on the first day
- Diarrhea, sometimes with mucus
- Moderate pain on palpation
- Nausea and lack of appetite
Diagnostics
The optimal first method is computed tomography of the abdomen with contrast: it shows thickening of the intestinal wall, its extent, the condition of the vessels and signs of complications, and also excludes other acute diseases. Colonoscopy is performed after the condition has stabilized, usually in the first two days: swelling, submucosal hemorrhages and ulcers with a clear boundary of healthy tissue are visible, a biopsy is taken. Laboratory assessments include inflammation, lactate levels, electrolytes, and renal function. Doppler ultrasound helps assess blood flow in large vessels.
- Computed tomography of the abdomen with contrast
- Colonoscopy with biopsy after stabilization
- Complete blood count and C-reactive protein
- Lactate, electrolytes, kidney parameters
- Dopplerography of abdominal vessels
- ECG and heart examination to find the cause
Treatment and prevention
In mild cases, treatment is supportive: temporary refusal to eat and feeding through an IV, fluid replacement, pain relief, and withdrawal of medications that impair blood flow. Antibiotics are prescribed according to indications. Most patients recover within a few days and symptoms disappear completely. Emergency surgery is needed for wall necrosis, perforation, peritonitis and continued deterioration. In the future, the main thing is to treat the cause: control blood pressure, arrhythmia, cholesterol and glucose levels, prevent dehydration, and stop smoking. All medications are prescribed by a doctor.
- Temporary fasting and intravenous support
- Replenish fluids and electrolytes
- Stopping medications that reduce blood flow
- Antibiotics according to indications
- Emergency surgery for necrosis and perforation
- Control of blood pressure, arrhythmia, cholesterol and glucose
- Stop smoking and drink enough