Small bowel ischemia (also called mesenteric ischemia) is a potentially life-threatening group of conditions that reduce blood flow to the small intestine (e.g., duodenum, jejunum or ileum). Symptoms can range from mild to severe depending on the cause.
It’s important to see your doctor if you have sudden, severe abdominal pain. Early diagnosis and treatment are essential for the best possible outcomes to restore digestive function.
What is small bowel ischemia?
Small bowel ischemia describes disorders that develop when blood flow to the small bowel is partially or completely blocked. The blockage usually occurs in one or more arteries that supply the small intestine.
Small bowel ischemia can be acute (start suddenly) or chronic (develop over time). Symptoms can be mild or severe, which can include abdominal pain, and diarrhea with or without bleeding. Small bowel ischemia requires prompt medical care to avoid damage to intestinal tissue that can lead to death.
When should I see a doctor about small bowel ischemia?
Small bowel ischemia can be a medical emergency, especially if it is acute. Seek immediate medical attention if you experience sudden, severe abdominal pain with or without bloody diarrhea, or any other possible symptoms.
What are the signs and symptoms of small bowel ischemia?
Small bowel ischemia produces a wide variety of symptoms. Some signs and symptoms of small bowel ischemia differ slightly between acute and chronic forms of the disease.
Signs and symptoms of acute small bowel ischemia may include:
- Sudden, severe abdominal pain
- Sudden, severe bloating
- Blood in the stool
- Mental confusion in older adults
- Nausea or vomiting
- Urgent need to have a bowel movement or sudden, forceful bowel movements
Signs and symptoms of chronic intestinal ischemia may include:
- Abdominal bloating
- Abdominal cramps or a feeling of fullness within 10 to 30 minutes after eating, usually lasting one to three hours
- Abdominal pain that gradually becomes more severe and frequent over weeks or months
- Nausea or vomiting
- Reluctance to eat because of subsequent pain
- Unintended weight loss
What are the different types of small bowel ischemia?
The categories of small bowel ischemia are:
- Acute intestinal ischemia: This is also called acute mesenteric ischemia and this type occurs quickly in the small intestine. Acute mesenteric ischemia is a surgical emergency in most cases. If this is not brought to medical attention immediately, it can result in death.
- Chronic intestinal ischemia: Also known as intestinal angina, this type of ischemia results from atherosclerosis, the buildup of cholesterol and other fatty deposits in your blood vessels that carry blood from the heart (e.g., arteries). Chronic ischemia develops gradually, but blood clots can also form, causing acute ischemia when blood flow is suddenly blocked.
- Mesenteric venous thrombosis: This form of ischemia occurs when the blood vessels that carry blood back to the heart (e.g., veins) become blocked. Blood subsequently backs up into the intestines, resulting in less blood with oxygen supporting the intestine and resultant ischemia. Venous thrombosis is the least common type and causes swelling and bleeding in the intestines as well.
What is the outlook for people with small bowel ischemia?
The outlook depends on the cause of the intestinal ischemia and how quickly you receive treatment. Acute small bowel ischemia requires immediate medical attention. If left untreated, the lack of blood supply to the intestines can quickly damage intestinal tissue and lead to tissue death. Chronic intestinal ischemia and mesenteric venous thrombosis usually has intermittent symptoms over weeks to months and requires treatment less acutely to avoid this changing to an acute process, or death.
What causes small bowel ischemia?
Small bowel ischemia occurs when a blockage prevents blood from flowing through the arteries to the intestines. The blockages can result from several possible causes:
- Atherosclerosis: Cholesterol builds up in the arteries leading to the intestines, reducing blood flow.
- Blood clots: Blood clots can partially or completely block arteries that supply blood to the intestines or, less commonly, the veins that carry blood from the intestines back to the heart.
- Hernia: Part of the intestine may protrude through a weak area of abdominal muscle, cutting off blood flow to the intestine.
- Low blood pressure: Extremely low blood pressure, which can result from trauma or heart failure (weakening of the heart’s ability to push blood forward), can reduce blood flow to the intestines, especially if arteries are already narrowed.
- Scar tissue: Tissue that grows after surgery or an injury can enlarge or obstruct the bowel, cutting off its blood supply.
What are the risk factors for small bowel ischemia?
Certain factors can increase your risk for small bowel ischemia, such as:
- Abnormal blood pressure: Blood pressure that is too high or too low increases your risk of small bowel ischemia.
- Atherosclerosis: Other conditions caused by atherosclerosis (clogging of your arteries), such as decreased blood flow to your heart (coronary artery disease) or legs (peripheral vascular disease), can increase your risk of developing small bowel ischemia. Factors that increase the risk of atherosclerosis include:
- Age 50 or older
- Conditions such as high blood pressure, diabetes or high cholesterol
- Blood-clotting conditions: Disorders, such as sickle-cell anemia, that increase your risk of blood clots may also increase your risk of small bowel ischemia.
- Heart and vascular (blood vessel) conditions: Your risk of small bowel ischemia is higher if you have congestive heart failure or an abnormal heartbeat, or if you have had a heart attack or stroke.
- Medications: Birth control pills and medications that cause blood vessels to expand or contract, such as certain medications for migraines or allergies, can increase the risk of small bowel ischemia.
- Use of illicit drugs: People who use cocaine and methamphetamine may be at a higher risk of intestinal ischemia.
- Recent surgery
Who should be evaluated for small bowel ischemia?
People who have any of the risk factors for small bowel ischemia and are experiencing any of the possible symptoms should see their doctor as soon as possible for a thorough examination and testing.
How is small bowel ischemia diagnosed?
Early diagnosis and prompt treatment are essential to improve your chances for a good-outcome. The longer you go without treatment, the higher the chance of irreversible damage to the small bowel and, in an acute case, death.
Your doctor will begin with a thorough evaluation that includes:
- Medical history: Your doctor will ask you about symptoms you are experiencing and discuss possible risk factors such as atherosclerosis.
- Physical exam: The doctor will examine you for abdominal pain, tenderness, or other signs.
- Lab tests: There is no specific blood test for small bowel ischemia, but a blood test can check for high white blood cell counts, a sign of inflammation or infection. Your doctor may also test your stool for blood.
Other tests your doctor may order include:
Imaging tests for small bowel ischemia
Your doctor can view your intestines and internal organs to check for narrowed or blocked arteries or veins. Imaging can also help rule out other causes that have similar symptoms.
For some imaging tests, you lie on a table while a technician uses sophisticated equipment to take detailed images of your abdomen and pelvis. Other tests involve inserting a thin tube into your artery to view the inside of your body and the blood vessels within your body more clearly. Your doctor will make sure you are comfortable and provide a sedative or anesthesia as necessary, depending on your procedure.
Possible tests include:
- CT scan: This imaging test uses special X-ray equipment to take cross-sectional images of your abdomen and pelvis, which are compiled into 3D images of the intestines.
- MRI scan: A large magnet and radio waves produce images of the intestines and other abdominal organs.
- Angiogram: The doctor inserts a catheter (a long, thin tube) into an artery in your groin and carefully guides it to the largest central blood vessel in your body (e.g., the aorta) to inject a dye. The dye flows into the arteries supplying blood to the small and large bowel, and then a technician takes X-rays to show blood flow. In many cases, the doctor can treat artery blockages during the same procedure (known as angioplasty) with or without placing a stent to provide a more permanent treatment.
- CT angiogram: This test uses a CT scan and appropriate timing of contrast injection into your blood vessels to view the dye in your intestinal arteries and clarify whether there are blockages.
Exploratory surgery to diagnose small bowel ischemia
If other tests don’t provide enough information for a definitive diagnosis, you may need exploratory surgery. Surgery enables doctors to diagnose and treat during the same procedure.
Gastrointestinal surgeons perform minimally invasive or open surgery. The goal is to find and either remove or bypass blockages in the blood vessels. Surgeons can also locate and remove diseased or dead tissue in the small intestine. If the surgeon needs to remove sections of intestine, the remaining healthy sections are frequently reconnected so the digestive system can continue to function. If this is not possible during the acute surgery, then a portion of bowel is brought through the skin as an outlet (also called an “ostomy”) where the contents of the bowel drain through this site and a bag on the skin outside the body covering this outlet will collect the contents of the digestive tract. If an ostomy is needed, this can frequently be reversed several months after the original surgery during a second surgical procedure where the bowel is re-attached to one another and an ostomy is no longer present.
What are the treatments for small bowel ischemia?
The goals of treatment are to restore blood supply to the intestines and maintain proper function in the digestive tract. Treatment options for intestinal ischemia vary depending on the cause of the condition and the severity of damage in the intestines.
Medications to treat small bowel ischemia
If you have small bowel ischemia but no damage to intestinal tissue, medications may be enough to manage the condition. Your doctor may recommend one or more medications, such as:
- Clot-busting medications to break up blood clots
- Blood thinners (anticoagulant medications) to prevent blood clots
- Antibiotics to treat or prevent infections
Angioplasty and stenting
Angioplasty is a minimally invasive catheter procedure that doctors use to open narrowed blood vessels. In many cases, doctors can perform angioplasty at the same time as an angiogram (technique for visualization of the blood vessels from contrast injection through the catheter). If necessary, the doctor can place a stent (tiny metal mesh tube) inside the artery or vein to keep it open.
Surgery for small bowel ischemia
Depending on your specific case, surgery might be the best treatment option. Typical surgical procedures include:
- Laparoscopy: The surgeon makes a few tiny incisions and uses small instruments to restore blood flow to the small bowel. Laparoscopy can remove blockages in blood vessels or create bypasses for blood to flow around blockages. This minimally-invasive procedure can result in less pain and a quicker recovery, compared to open surgery.
- Laparotomy: In some cases, open abdominal surgery may be the best option to repair damaged small intestinal tissue and restore proper blood flow. The surgeon typically makes one long incision to access the area to be treated. The goal of laparotomy is to remove sections of the intestine that have dead tissue and reconnect the healthy portions of the intestines.
Am I at risk of developing other conditions?
Small bowel ischemia can lead to complications such as:
- Rupture: A hole in the intestinal wall can form, causing the contents of the intestine to leak into the abdominal cavity.
- Peritonitis: A rupture can lead to peritonitis, a serious infection and inflammation of the abdominal cavity lining.
- Scarring or narrowing of your colon: Even if the intestines recover from ischemia, scar tissue that narrows the intestines can form during the healing process.
- Tissue death: Sudden, complete blockage of blood flow to your intestine can cause gangrene (tissue death) of intestinal tissue.
Author(s) and Publication Date(s)
Paul Feuerstadt, MD, FACG, Gastroenterology Center of Connecticut – June 2019