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NOTE: Some of the information provided contains graphic, medical images which individuals may find upsetting

Diverticular disease is a very common condition affecting the colon. (The colon is often called the large intestine or lower bowel). More than half of people aged over 70 in Britain have the condition.

It gets its name because, in this disease, the colon forms many ‘diverticula’. Diverticula are small pouches created when the thin lining of the bowel protrudes through narrow gaps in its wall. The wall is also often thicker than normal. Only a small minority of patients (around 10-20%) develop any problems due to the pouches.

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How and why does it develop?

It is likely to be due to our diet. Native African people rarely develop this condition, probably because of their high intake of dietary fibre (‘roughage’).

When there is little fibre in the diet, the stools are often small and hard. This can cause the pressure in the colon to increase forcing the pouches through the bowel wall.

What are the symptoms?

Most people have no symptoms. But, because the wall is thicker, the tube is narrower. This can cause pain in the lower part of the stomach, often on the left side. The bowels may become irregular, sometimes with hard pellety stools and there is often a sensation of bloating. Some patients report loose motion. The pouches can also cause bleeding.

These symptoms can also occur in other important bowel diseases, particularly irritable bowel syndrome (IBS) and bowel cancer.

Is it dangerous?

Occasionally, the diverticula can become infected. This is a condition called ‘acute diverticulitis’. It leads to more severe pain often on the left side and a fever along with feeling unwell. It may require hospital admission but usually gets better with antibiotics.

Very rarely, the infection leads to an abscess (collection of pus) or even perforation (a hole in the bowel) of the bowel. Usually patients with these conditions have severe pain, and require admission to hospital. However surgery for Diverticular Disease is hardly ever required. Out of a hundred people with the condition, no more than one will ever need an operation.

Are tests needed?

Although Diverticular Disease is much more common, the symptoms it causes can mimic those of bowel cancer. So tests are often done mainly to rule out cancer.

The usual test that is done is either a telescope examination (colonoscopy or flexible sigmoidoscopy) or a CT scan. Occasionally both are required.

Is treatment required?

Reassurance that the symptoms are not due to a serious disease like bowel cancer is often enough.

A diet with extra fibre may prevent the condition from getting worse but won’t get rid of the diverticula that are already there.

A high fibre diet often improves the symptoms but occasionally will make them worse. Your symptoms are what count, not how much fibre you are eating.

Several foods are high in fibre – cereals, whole-meal bread, and fruit.

‘Medicinal’ fibre can be bought from the chemist or prescribed by a doctor.

Is an operation ever needed?

Yes, but it is rare. If the bowel tube becomes very narrow (‘stricture’) the symptoms can be severe enough to warrant surgery to prevent a complete blockage.

Occasionally, the bowel sticks to the bladder or vagina and makes an unnatural connection between the two known as a fistula. This occurs rarely but usually requires an operation to fix it. Another reason for surgery is if you have recurrent admissions to hospital due to infections. The decision to operate is made on an individual basis after your surgeon assesses your particular circumstances. These operations can be done with single large incision (open surgery) or multiple small incisions (‘key-hole’ via laparoscopic or robotic surgery).

Urgent surgery is sometimes needed for the most serious complications of diverticular disease such as abscess or perforation.

Further information