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Small Bowel Ischemia
Small Bowel Ischemia Overview
- What is small bowel ischemia?
Small bowel ischemia (also called mesenteric ischemia) is a potentially life-threatening reduction in the blood flow to the small intestine causing damage to the bowel (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.
Small bowel ischemia occurs when the blood flow to the small bowel is reduced or blocked. This usually happens because one or more arteries that supply blood to the small intestine become narrowed or blocked. Without enough blood, the small intestine does not get the oxygen it needs to function properly. If the lack of blood flow is severe or prolonged, it can cause injury to the intestinal tissue and, in some cases, lead to tissue death (necrosis).
Small bowel ischemia can be divided based on the timing of onset into acute (start suddenly) or chronic (develop over time). Symptoms can be mild or severe, which can include abdominal pain, and diarrhea with or without bloody stools. Small bowel ischemia requires prompt medical care.
- When should I see a doctor about small bowel ischemia?
Sudden onset (acute) small bowel ischemia is a medical emergency. Seek immediate medical attention if you experience sudden, severe abdominal pain with or without bloody diarrhea.
- 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 it occurs quickly when a blood clot or thrombus suddenly blocks the blood supply to the 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 develops gradually as a result of atherosclerosis, the buildup of cholesterol and other fatty deposits in the blood vessels that carry blood from the heart to the intestine (e.g., arteries).
- 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 underlying cause of the intestinal ischemia and how quickly treatment is provided. 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. In contrast, chronic intestinal ischemia and mesenteric venous thrombosis often develops more slowly, with intermittent symptoms appearing over weeks to months. This condition still requires treatment to prevent from worsening into acute ischemia, which could be life-threatening.
Causes
- What causes small bowel ischemia?
Small bowel ischemia occurs when blood flow to the intestines is reduced or blocked. The blockages can result from several possible causes:
- Blood clots: A blood clot can travel from another part of the body and block a blood vessel that supplies the intestine (embolism). A clot can also form directly in the blood vessels of the intestine (thrombus). Less commonly, a clot can block the veins that carry blood away from the intestine.
- Atherosclerosis: Fatty deposits of cholesterol can build up inside the arteries over time, reducing blood flow to the intestines.
- Hernia: Part of the intestine can push through a weak area of abdominal wall. This may trap the intestine and cut off its blood supply.
- Low blood pressure: Severe blood loss, dehydration, heart failure or a heart attack can cause extremely low blood pressure, and reduce the blood flow to the intestines, especially if arteries are already narrowed.
- Scar tissue (adhesions): Scar tissue that forms after abdominal surgery or an injury can twist of block the intestine, cutting off its blood supply.
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
Acute small bowel ischemia happens suddenly and is a medical emergency, some symptoms may include:
- Sudden, severe abdominal pain, often around the belly button
- Sudden abdominal bloating or swelling
- Nausea or vomiting
- Blood in the stool or black, tar-like stools
- Fever
- Confusion or changes in alertness, especially in older adults
- Urgent need to have a bowel movement or sudden, forceful bowel movements
Signs and symptoms of chronic intestinal ischemia:
Chronic intestinal ischemia develops more gradually over time. Symptoms may include:
- Cramping abdominal pain or fullness that starts10 to 30 minutes after eating, usually lasting 1-3 hours
- Abdominal pain that gradually becomes more severe and frequent over weeks or months
- Abdominal bloating
- Nausea or vomiting
- Diarrhea
- Fear of eating due to pain after meals
- Unintended weight loss
If symptoms are sudden or severe, it is important to seek medical attention right away, as early treatment can prevent serious complications.
Risk Factors
- What are the risk factors for small bowel ischemia?
Several health conditions and lifestyle factors can increase your risk of developing small bowel ischemia.
- Abnormal blood pressure: Blood pressure that is very high or very low can affect the blood flow to the intestines.
- Atherosclerosis: Cholesterol plaque can build up inside the blood vessels and reduce blood flow. People with blocked arteries in the heart (coronary artery disease) or legs (peripheral vascular disease), are at higher risk. Factors that increase the risk of atherosclerosis include:
- Age 50 years or older
- Smoking
- High cholesterol
- High blood pressure
- Diabetes
- Conditions that increase blood clotting: Some inherited or acquired blood-clotting disorders can make blood clots more likely to form. Certain blood cancers and sickle cell disease can also increase risk. In people who require blood thinners (anticoagulants), not taking these medications as prescribed may further increase the risk of blood clots and small bowel ischemia.
- Heart and blood vessel conditions: Your risk of small bowel ischemia is higher if you have congestive heart failure or an abnormal heartbeat (arrhythmias), or if you have had a heart attack or stroke.
- Cirrhosis (scarring of the liver): Cirrhosis can increase the risk of blood clots forming in the veins of the abdomen, which may affect blood flow to the intestines.
- Medications: Some medications, including estrogen-containing birth control pills and certain medicines used to treat migraines or allergies, may increase the risk of reduced blood flow or blood clots in some people.
- Use of illicit drugs: Cocaine and methamphetamine can cause blood vessels to narrow suddenly, reducing blood flow to the intestines.
- Recent abdominal surgery: Surgery in the abdomen can sometimes increase the risk of blood clots or scar tissue that affects blood flow
- Severe dehydration: Significant fluid loss can lower blood pressure and reduce blood flow to the intestines.
Diagnosis
- 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, especially sudden onset severe abdominal pain, 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.
Imaging tests for small bowel ischemia
Your doctor may order imaging tests to look for narrowed of blocked blood vessels in the intestines. Imaging can also help rule out other conditions that may cause similar symptoms, such as infection, inflammation, or bowel obstruction.
Some imaging tests take detailed pictures of your abdomen and pelvis while you lie on a table. Other tests involve inserting a thin tube into your artery to look directly at the blood flow in your body. Your doctor will make sure you are comfortable and provide a sedative or anesthesia as necessary, depending on your procedure.
Possible tests include:
- Duplex ultrasound: Uses sound waves to look at blood flow in the blood vessels of the abdomen. It does not use radiation and is completely noninvasive. This test can’t visualize deeper abdominal vessels, so it is not always definitive.
- CT scan: Uses special X-ray equipment to take cross-sectional images of your abdomen and pelvis, allowing to visualize the intestines and surrounding organs in detail.
- MRI scan: A large magnet and radio waves produce images of the intestines and other abdominal organs. It does not use radiation but takes longer than CT scan.
- CT angiogram: This special type of CT scan that uses contrast dye injected into a vein to highlight blood flow in the arteries and veins of the intestines. This is one of the most commonly used and most accurate tests to diagnose small bowel ischemia because it can quickly show blockages and reduced blood flow.
- Angiogram: A thin tube (catheter) is inserted into a blood vessel in the groin or wrist and guided to the arteries supplying the intestines. Contrast dye is injected, and X-rays are taken to show blood flow. In some cases, treatment can be done during the same procedure, such as opening a blocked artery or placing a stent to improve blood flow.
Exploratory surgery to diagnose small bowel ischemia
In some cases, imaging tests do not give enough information, and doctors may recommend exploratory surgery. During this procedure, surgeons directly look at the intestines and blood vessels. Surgery can confirm the diagnosis and allow treatment at the same time.
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 dead tissue in the small intestine. f 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.
Treatment
- 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 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 in the abdominal wall 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 or perforation: A hole in the intestinal wall can form, causing the contents of the intestine to leak into the abdominal cavity.
- Peritonitis: A rupture of the bowel 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, Hamden, CT – Published June 2019
Jellyana Peraza, MD, Yale School of Medicine, New Haven, CT – Updated June 2026.