Patient information from BMJ

Ischaemic bowel disease: what is it?

Last published:Sep 14, 2022

Ischaemic bowel disease can happen when the blood supply to your intestines (bowels) becomes restricted. It can come on suddenly or develop over time. Treatment can help many people, but it is a serious condition that can be life threatening.

What is ischaemic bowel disease?

Like all the body’s organs, the digestive system needs a healthy supply of blood to work properly. Blood brings oxygen and nutrients and carries away waste products. If the blood flow to the intestines is restricted for any reason it can cause ischaemic bowel disease. The word ‘ischaemia’ means restricted blood supply.

Ischaemic bowel disease is not one specific condition. The name covers any problems that can be caused by reduced blood supply to the bowel.

But you might hear your doctor call it either colonic or mesenteric ischaemia.

• Colonic ischaemia affects the part of the bowel called the large intestine.

• Mesenteric ischaemia affects what's called the small intestine. This tends to be the more serious of these two types.

These problems can have various causes, but the most common is a blood clot in an artery that leads to the bowel. These blood clots often develop near the heart, then travel along the artery and become lodged near the bowel. Ischaemic bowel disease is more common in people with heart disease.

Other causes of ischaemic bowel disease include:

• Swollen walls in the blood vessels. The swelling narrows the blood vessels, which reduces the flow of blood. This can be caused by conditions such as rheumatoid arthritis and lupus 

• Something pressing on an artery, such as another swollen body tissue or a tumour 

• Other conditions that cause reduced blood flow, such as heart failure 

• Some medicines and some recreational drugs 

• An infection 

• Recent surgery. 

Ischaemic bowel disease is more common in women than in men. It is also more common in older people and in people who have smoked for many years.

What are the symptoms?

Ischaemic bowel disease can happen suddenly or it can develop gradually over time. This means that the symptoms can come on suddenly and be very severe or they can be mild to begin with and gradually get worse.

• Ischaemic bowel disease that comes on suddenly is called acute ischaemic bowel disease.

• Ischaemic bowel disease that comes on slowly over time is called chronic ischaemic bowel disease

Chronic ischaemic bowel disease can be hard to diagnose, as the symptoms are similar to those of many conditions that can cause abdominal discomfort. This means that many people are not diagnosed until they are seriously ill. 

The main symptoms are:

• Pain and tenderness in your abdomen (tummy) 

• Blood in your stools 

• Diarrhoea, and

• Weight loss. This can happen because the pain is worse after meals, which puts some people off eating. 

If your doctor thinks you might have ischaemic bowel disease, he or she won’t be able to tell just by examining you. You will need to have a blood test and a scan.

This might be an external scan, such as an x-ray or a CT (computerised tomography) scan. Or you may need an internal procedure, such as a colonoscopy, where a small camera is inserted into the rectum on the end of a tube. This helps your doctor identify the problem and see how severe it is.

What to expect in the future

The follow-up care that you need will depend on whether you needed surgery. For more information on surgery and other treatments, see our leaflet Ischaemic bowel disease: what treatments work?

If you didn’t have surgery you might need to have tests and procedures so that your doctor can check for any damage to your digestive system. 

If you had surgery you will need regular check-ups to make sure you are healing well. But, whether you had surgery or not, you will need check-ups so that your doctor can look out for signs of anything that might cause another episode of ischaemia.

You will also need treatment for any other problems that might have caused the ischaemia. 

You will need to be aware of the symptoms of bowel ischaemia returning. If you have any abdominal pain, bloating, bloody stools, nausea, or vomiting, seek medical help straight away.

And it’s vital that you take your follow-up medicines as instructed by your doctor. 

Unfortunately an episode of bowel ischaemia can be fatal, especially if it was diagnosed late and there is already a lot of damage. The chances of survival also depend on which blood vessels are involved and how bad the blockage is. 

The outlook is better for people with chronic ischaemic bowel disease. With treatment, between 70 and 90 in 100 people survive. For people whose large intestine is affected, rather than their small intestine, the outlook is even better.

But acute ischaemic bowel disease tends to be more serious. More than half of people with this type of ischaemia will die.