Intestinal ischemia

Intestinal Ischaemia is a term used to describe a variety of disorders caused by inadequate blood flow because of a blood vessel blockage. Venous blockages may occur but arterial blockages are more common. Three arteries that are predominantly affected are celiac artery, superior mesenteric artery and inferior mesenteric artery. It can affect both small and/or large intestine.

Types of Intestinal Ischemia

Depending upon the duration and location of the disease, it can be divided into:

  • Acute or chronic
    1. Acute intestinal ischemia
    2. Chronic intestinal ischemia
  • Small intestine or large intestine
  • Occlusive or non-occlusive
  • Arterial or venous occlusion

Causes

  • Hernia: when a part of the intestine protrudes through the lower abdominal wall, most commonly into the inguinal canal (in the groin) This condition is more common in males.

  • Adhesions: These refer to the formation of scar tissue between the small or large intestine and inner lining of abdominal wall and organs in the abdominal cavity. Blood flow is obstructed due to the formation of these adhesions causing intestinal ischemia.

  • Embolus: It is composed of clotted blood cells that dislodges itself and moves in the bloodstream and can cause obstruction of the arteries, usually superior mesenteric artery. This is the most common cause of acute intestinal ischemia and can occur due to congestive heart failure or a cardiac arrhythmia (irregular heartbeat).

  • Atherosclerosis: It involves formation of an atheroma which forms due to fatty deposits in the blood vessels. It can slow down or block the blood flow depending on its size. This is seen in patients with chronic intestinal ischemia.

  • Venous thrombosis: It occurs due to formation of a thrombus or blood clot in the veins. This is less common as compared to arterial obstruction and is known to occur in patients with liver disease, cancer or clotting disorders.

  • Hypotension: Low blood pressure due to shock, heart failure or chronic renal disease may cause slow down of blood flow. This condition in presence of arterial insufficiency exaggerates the impaired blood flow and can cause an acute attack of intestinal ischemia.

  • Malignancy: Tumours which cause venous or arterial compression

Signs & Symptoms

Symptoms of the disease can be divided on its occurrence: acute or chronic

Acute Intestinal Ischemia

  • Sudden severe abdominal pain
  • Frequent and forceful bowel movements
  • Passage of bloody stools
  • Abdominal tenderness
  • Nausea
  • Vomiting
  • Fever
  • Fatigue
  • Mental confusion

Chronic Intestinal Ischemia

  • Abdominal pain usually after eating that ranges from mild to severe, lasting from one to three hours
  • Fear of eating or change in eating habits due to abdominal pain
  • Diarrhea
  • Nausea
  • Vomiting
  • Bloating
  • Blood tinged stools

Risk factors

  • Age: Adults over the age of 60 years are most commonly affected.
  • High cholesterol diet: Predispose to fatty deposits in the vessels causing atherosclerosis
  • Low blood pressure
  • Heart conditions: Like congestive heart failure increases the risk of the disease.
  • Medications
    1. Migraine medications
    2. Birth control pills
    3. Vasopressive drugs such as dobutamine
  • Having unprotected sexBlood clotting disorders such as deficiency of Protein C and Protein S, which prevents clotting.
  • Previous abdominal surgery: Scar formation can occur around the small or large intestine causing obstruction of blood flow.
  • Smoking
  • Blood tests: White blood cell count and Lactic acid level are determined. Increase in these identities may indicate intestinal ischemia.

  • Plain abdominal X-ray:  Often show normal or non-specific findings. They can be used to rule out other possible causes.

  • Computed tomography (CT) scan:  May show gas in the intestinal walls, portal vein or mesenteric vein. Bowel wall thickening or dilatation can be seen. Perforation in the bowel can also be seen. Mesentric oedema or swelling may be present depending on the duration of the disease.

  • Angiography

    It is the gold standard to diagnose the cause of the disease. It helps in determining whether the disease is of occlusive or non-occlusive nature. A thin, flexible tube called catheter is inserted into an artery in the groin area. Contrast dye is injected through this tube to visualize the abnormalities in the blood vessels and X-ray images are taken.

    This technique is also used to treat blockages in an artery by injecting medication through the tube.

  • Duplex ultrasound

    This test is done to assess the blood flow in the arteries and veins. It can also reveal any blockage in the blood vessels.

    A wand called transducer is moved over the area to be examined. Sound waves sent by it are measured by the computer, which changes them into images.

It depends upon the underlying cause and severity of the disease.

Acute Intestinal Ischemia

Medical care
  • Supportive therapy including intravenous fluid and oxygen therapy.
  • Medications:
    • Anti spasmodic drugs like Papaverine
    • Thrombolytics injected through an angiogram catheter
    • Anti coagulants like heparin
Surgical care
  • Angioplasty: It involves use of an inflated balloon at the end of a catheter to compress the fatty deposits and to widen the blocked artery or vein. This improves blood flow in the blood vessel. A metallic stent may also be placed in the blood vessel to keep it stretched.

  • Embolectomy:Surgical removal of the embolus is done to improve the blood flow.

  • Aortomesenteric bypass and resection of bowel:This surgery is done in case, gangrene develops.

Chronic Intestinal Ischemia

Medical care
  • Nitrate therapy for short-term relief
  • Antispasmodic drugs like Papaverine
  • Anticoagulants like heparin
  • High frequency of developing malnutrition, infarction and sepsis warrants surgical care
Surgical care
  • Transaortic endarterectomy: To remove plaque deposits from the celiac or mesenteric artery to remove the obstruction to bloodflow.

  • Bypass Surgery: Using graft from another area of the body to repair the blocked Blood vessel.