Intestinal infarction is a life-threatening medical emergency that occurs when blood flow to the intestines becomes severely reduced or completely blocked, causing intestinal tissue to die from lack of oxygen. This uncommon but extremely dangerous condition affects thousands of people each year, most often those over 60 with heart or blood vessel disease, and requires immediate medical attention to prevent fatal complications.

Understanding How Common Intestinal Infarction Is

Intestinal infarction, also known as acute mesenteric ischemia, is fortunately not a common condition, but when it does occur, it carries extremely serious consequences. The condition affects approximately 1 to 2 people for every 1,000 hospital admissions, making it a relatively rare cause of abdominal pain.^[1] However, these numbers may underrepresent the true scope of the problem, as the condition can be difficult to diagnose and some cases may go unrecognized until it is too late.

Despite its rarity, intestinal infarction has an alarmingly high death rate. When blood flow to the intestines stops suddenly, mortality rates range between 60% and 80% in acute cases.^[2] Even with modern medical care and surgical techniques, more than half of people who develop this condition do not survive. This high mortality rate exists primarily because the symptoms can be vague and easily confused with less serious digestive problems, leading to delays in diagnosis and treatment.

The condition becomes more common as people age, particularly affecting those over 60 years old. The risk is especially elevated in individuals who already have diseases affecting their heart or blood vessels, such as irregular heart rhythms like atrial fibrillation (a condition where the heart beats irregularly and often rapidly), hardening of the arteries, or blood clotting disorders.^[3] The connection between age and risk exists because blood vessels naturally become less flexible and more prone to blockages as we get older, and older adults are more likely to have accumulated plaque in their arteries or developed heart conditions that can lead to blood clots.

What Causes Blood Flow to Stop in the Intestines

The intestines depend on a constant supply of oxygen-rich blood to stay alive and function properly. This blood arrives through major arteries called the superior mesenteric artery and inferior mesenteric artery. The superior mesenteric artery supplies blood from the lower part of the small intestine to about two-thirds of the large intestine, while the inferior mesenteric artery supplies the remaining portion of the colon down to the rectum.^[4] When something interrupts this blood supply for long enough, the intestinal tissue begins to die, creating a medical emergency.

Several different problems can cause intestinal infarction. One of the most common causes is a blood clot or embolus that travels through the bloodstream and gets stuck in one of the arteries feeding the intestines. This happens most often in people who have had a heart attack or who have atrial fibrillation, because these conditions can cause clots to form in the heart that then break loose and travel through the blood vessels.^[5] When such a clot reaches the narrower arteries supplying the intestines, it can completely block blood flow.

Another major cause is the gradual narrowing of the intestinal arteries due to atherosclerosis, which is the buildup of fatty deposits called plaque inside the blood vessel walls. Just as this process can cause heart attacks when it affects heart arteries, it can cause intestinal infarction when it affects the arteries to the intestines. The narrowed arteries may not cause problems immediately, but they can suddenly become completely blocked or may fail to provide enough blood when the intestines need more during digestion.^[6]

Less commonly, the problem originates in the veins rather than the arteries. The veins that carry blood away from the intestines can become blocked by blood clots, preventing blood from flowing through the intestinal tissue. This type of blockage is more common in people with liver disease, cancer, or disorders that make their blood clot too easily.^[7]

Sometimes intestinal infarction occurs without a blockage at all. Very low blood pressure in people who already have narrowed intestinal arteries can reduce blood flow enough to cause tissue damage. This often happens in people who are already seriously ill with other medical problems or who have undergone major surgery.^[8]

Physical problems can also cut off blood supply to the intestines. A hernia, which occurs when the intestine pushes through a weak spot in the abdominal wall or becomes twisted and tangled, can pinch off blood vessels and stop blood flow. Similarly, adhesions, which are bands of scar tissue that form after abdominal surgery, can trap loops of intestine and compress their blood supply if left untreated.^[9]

Who Is Most at Risk for Developing This Condition

While intestinal infarction can theoretically affect anyone, certain groups of people face significantly higher risk. Age is one of the most important risk factors, with the condition being far more common in people over 60 years old. As people age, their blood vessels lose elasticity, plaque accumulates more readily in artery walls, and the risk of heart rhythm problems increases, all of which contribute to higher risk.^[10]

People with heart and circulatory system diseases face substantially elevated risk. Atrial fibrillation, an irregular heart rhythm that causes the heart’s upper chambers to quiver instead of beating effectively, is a particularly important risk factor because it allows blood to pool in the heart chambers where clots can form. These clots can then break loose and travel to the intestinal arteries. Similarly, people with coronary artery disease, which affects the heart’s own blood supply, often have similar plaque buildup in other arteries throughout the body, including those feeding the intestines.^[11]

Individuals with high blood pressure and high cholesterol levels are at increased risk because these conditions accelerate the development of atherosclerosis. Diabetes also elevates risk, as it damages blood vessels over time and increases the likelihood of both clotting problems and atherosclerosis. People with heart failure, a condition where the heart cannot pump blood effectively throughout the body, may not have enough blood pressure to maintain adequate flow to the intestines, especially during digestion when the intestines need more blood.^[12]

Having had previous surgery on the abdomen increases risk not only because of adhesions that can form, but also because scar tissue can affect normal blood vessel patterns. People with peripheral artery disease, which causes narrowing of blood vessels in the legs and arms, often have similar problems in their abdominal blood vessels. Those with liver disease or cancer face increased risk for the venous form of the condition, where clots block the veins draining blood from the intestines rather than the arteries supplying it.^[13]

Recognizing the Warning Signs and Symptoms

The most common and prominent symptom of intestinal infarction is sudden, severe abdominal pain. This pain typically comes on quickly and is intense from the very beginning, which distinguishes it from many other causes of belly pain that start mild and gradually worsen. People often describe the pain as excruciating and unbearable, so severe that they cannot sit still or find a comfortable position.^[14]

What makes this condition particularly dangerous and difficult to diagnose is that despite the severity of the pain, the abdomen may not be very tender when a doctor presses on it during examination. This mismatch between the intensity of pain the patient feels and the relatively mild findings during physical examination is sometimes called “pain out of proportion to exam findings,” and it should raise suspicion for intestinal infarction.^[15]

Beyond abdominal pain, people with intestinal infarction often experience an urgent and forceful need to have a bowel movement. They may develop diarrhea, and the stool frequently contains blood or appears bloody. The presence of blood in the stool occurs because the dying intestinal tissue bleeds, and this blood passes through the digestive tract.^[16]

Nausea and vomiting are common symptoms, as the dying intestinal tissue cannot function normally and the body reacts to the severe injury. Many people lose their appetite completely and feel unable to eat anything. The abdomen may become swollen and distended as gas and fluid accumulate in the damaged intestines. Some people develop fever as the body responds to tissue death and potential infection.^[17]

In older adults, mental confusion can be a symptom of intestinal infarction. This happens because the body is under severe stress, blood pressure may drop, and toxins from dying tissue enter the bloodstream. Family members or caregivers might notice that the person seems disoriented, has trouble thinking clearly, or acts differently than usual, and this change in mental state combined with abdominal pain should prompt immediate medical evaluation.

The symptoms can vary somewhat depending on whether the condition affects primarily the small intestine or the large intestine. People with blockage in the arteries to the large intestine may have milder pain, may not appear as severely ill initially, and are more likely to have bloody diarrhea. Those with blockage affecting the small intestine tend to appear more acutely ill with more severe pain.^[18]

Steps to Prevent Intestinal Infarction

While it is not always possible to prevent intestinal infarction, many cases can be avoided by managing the underlying conditions that increase risk. The most important preventive measures focus on protecting the health of blood vessels and preventing blood clots from forming.

Managing cardiovascular risk factors is crucial. People with high blood pressure should work with their healthcare providers to keep it well controlled through medication, dietary changes, and lifestyle modifications. Similarly, keeping cholesterol levels in a healthy range through diet, exercise, and medications when necessary can slow the development of atherosclerosis and reduce the risk of arterial blockages.^[19]

For people with irregular heart rhythms like atrial fibrillation, taking blood-thinning medications as prescribed by a doctor can significantly reduce the risk of blood clots forming in the heart and traveling to the intestinal arteries. These medications require careful monitoring but are highly effective at preventing clot-related complications.

Quitting smoking is one of the most important steps anyone can take to reduce their risk. Tobacco use damages blood vessels, accelerates plaque buildup, and increases blood clotting risk. The damage caused by smoking can begin to reverse after quitting, and the risk of vascular problems decreases over time.^[20]

Eating a nutritious diet benefits vascular health in multiple ways. A diet rich in fruits, vegetables, whole grains, and lean proteins while limiting saturated fats, cholesterol, and processed foods helps maintain healthy blood vessels and reduces atherosclerosis risk. This type of eating pattern also helps with weight management, blood pressure control, and diabetes prevention, all of which contribute to lower risk.

For people with diabetes, maintaining good blood sugar control protects blood vessels from damage and reduces the risk of vascular complications including intestinal infarction. This requires following the treatment plan prescribed by healthcare providers, monitoring blood sugar levels, taking medications as directed, and making appropriate dietary choices.

Hernias should be evaluated and treated promptly rather than ignored. While not all hernias require surgery, those that do should be repaired before they cause complications like intestinal infarction. Anyone who has had previous abdominal surgery and experiences symptoms of bowel obstruction should seek medical attention quickly, as adhesions from past surgery can sometimes be treated before they cause complete blockage and tissue death.

How the Disease Affects the Body

To understand what happens during intestinal infarction, it helps to know how the intestines normally work and what they need to stay healthy. The intestines are hollow tubes that move food through the digestive system, absorbing nutrients and water along the way. The intestinal walls are made up of multiple layers of tissue, and every cell in these layers needs a constant supply of oxygen and nutrients delivered by blood.

Blood reaches the intestines through large arteries that branch into progressively smaller vessels until they form tiny capillaries that run throughout the intestinal tissue. In these capillaries, oxygen moves from the blood into the cells, and carbon dioxide and waste products move from the cells into the blood. The blood then flows into veins that carry it away from the intestines back toward the heart.^[21]

When an artery becomes blocked or blood pressure drops too low, not enough oxygen-rich blood reaches the intestinal tissue. At first, the cells try to function without adequate oxygen, but they cannot survive this way for long. Within hours, cells begin to die, starting with those in the innermost lining of the intestine. This layer, called the mucosa, is particularly vulnerable because it has high energy demands to perform its functions of absorbing nutrients and producing digestive fluids.^[22]

As cells die, the intestinal lining becomes inflamed, swollen, and begins to break down. The inflammation causes the tissue to leak fluid, leading to swelling and accumulation of liquid in the abdomen. The damaged lining can no longer prevent bacteria from crossing the intestinal wall. The intestines normally contain trillions of bacteria that help digest food, but these bacteria are meant to stay inside the intestinal tube. When the intestinal wall is damaged, these bacteria can escape into the bloodstream or the abdominal cavity.

If blood flow is not restored quickly, the tissue death extends deeper through all layers of the intestinal wall. When the full thickness of the intestine dies, it is called gangrene or transmural infarction. Dead tissue can no longer contain the intestinal contents, and holes may develop allowing bacteria and digestive fluids to spill into the abdominal cavity, causing a condition called peritonitis, which is inflammation and infection of the abdominal lining.^[23]

The spread of bacteria into the bloodstream leads to sepsis, a life-threatening condition where the immune system’s overwhelming response to infection damages the body’s own tissues and organs. Sepsis can cause blood pressure to drop dangerously low, multiple organs to fail, and can quickly become fatal without aggressive treatment.

The body tries to respond to the tissue injury by increasing inflammation, which actually makes the situation worse. The inflammatory response causes blood vessels to leak fluid, leading to low blood pressure. It can cause blood clots to form in small vessels throughout the body, further reducing blood flow to organs. The kidneys may fail, the lungs may fill with fluid, and the heart may struggle to pump effectively.

Certain areas of the colon are particularly vulnerable to ischemia. Two regions called “watershed areas” receive blood supply from the margins where different arteries meet, so they have less robust circulation than other parts. These areas, the splenic flexure (where the colon bends near the spleen) and the rectosigmoid junction (where the colon joins the rectum), account for about 70% of cases affecting the large intestine.^[24]

Intestinal ischemia requires at least a 75% reduction in blood flow lasting more than 12 hours to cause tissue death, though the timeline can vary depending on the severity of the blockage, the person’s overall health, and whether collateral blood vessels can partially compensate for the blocked artery. The longer tissue goes without adequate blood supply, the more extensive the damage becomes and the higher the risk of complications and death.