Diverticular disease explained

How common is diverticular disease?

Diverticular disease is extremely common. Between one-third and a half of the population of Western Europe and North America will get diverticula in the colon during their lifetime. The likelihood of having the condition increases as we get older. Less than one person in 20 has the condition before the age of 40, rising to a quarter of us by 60 years of age and two-thirds by the age of 85. Most people with diverticula suffer no symptoms or complications whatsoever. Indeed, as many as three people in four with diverticula are quite unaware they have the condition. It is just not clear why a minority end up being unwell.

What actually is diverticular disease?

Diverticulum is a Latin term meaning a side-branch or pouch. When such pouches stick outwards from the wall of the large intestine (also known as the colon) we call this diverticular disease. It can be hard to understand how these pouches occur but try to imagine your large intestine as being similar to a bicycle tyre with a soft easily stretched inner tube and a tough outer tube. If a hole is made in the outer tube, when the inner tube inflates, it squeezes out through the hole. Like the tyre, our intestine has a soft flexible lining surrounded by a tougher outer tube of muscle. There may not be a hole in the outer tube as such but where there is a weakness in the muscle, the inner layer can push through it to form the pouch that we call a diverticulum. The term diverticula is used when there is more than one diverticulum in the bowel. 

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What is the difference between diverticular disease and diverticulitis?

The medical terms can seem a little confusing. If diverticular disease is so common yet causes no symptoms, is it fair to call it a disease? Some authorities call uncomplicated diverticular disease by the name diverticulosis. Diverticular disease is a term mainly used in people who develop symptoms. You may hear the term ‘diverticulitis’ which strictly means the condition that occurs when a single diverticulum or several diverticula become inflamed.

Where do diverticula occur in the intestine?

By far the most common site for diverticula is in the lower part of the colon. Diverticula do occasionally occur in the small intestine and some other parts of our insides but here we focus just on those that occur in the colon.

Why does it happen to so many people?

The answer almost certainly relates to our diet. We eat far less fibre in our highly refined Western diet than people who live in developing countries, where diverticular disease is much less common. Because most of us in the affluent West just don't eat enough fibre, this increases our chances of getting diverticular disease. 

Diverticular Disease: External appearance

 Diverticular Disease: Cross section