What is diverticular disease?

A diverticulum is the name given to a small bulge or pouch that occurs on the wall of the large bowel (colon). These bulges develop over a period of years and are increasingly common with advancing age. Typically, the sigmoid colon in the lower left abdomen is involved although any part of the colon can be affected. Approximately half the population in the UK over 70 will have multiple bulges in the bowel - this is termed diverticular disease. The condition may also affect young people.

Diverticular disease is thought to be caused by overactive muscle in the bowel wall that increase the pressure inside the bowel; pouches form at weak points and can become permanent. The increased pressure may arise due to lack of fibre in the diet. Once formed the diverticula do not go away, but it is rare to need any surgical treatment for the condition.


For most people, diverticular disease causes no symptoms; it is a frequent incidental finding when the bowel is being investigated. However, it can lead to a variety of complications:

  • Day to day problems – such as constipation or tummy pains
  • Acute diverticulitis – here there is inflammation of the bowel, associated with significant pain and usually a fever. This develops over a short period of up to 24hrs and lasts 3-7 days. Mild episodes can settle without any specific treatment and more severe ones require admission to hospital
  • Abscess – acute diverticulitis can lead to an abscess forming inside the tummy next to the bowel
  • Fistula – rarely an abscess can erode into a nearby structure such as the bladder or vagina, leaving a connection between the bowel and that organ (this is a fistula). This can be very unpleasant because of discharge and repeated infections.
  • Perforation – perforation is very uncommon and presents as an emergency. Most people who get a perforation have no previous symptoms of diverticular disease.
  • Bleeding – occasionally a small blood vessel within the bowel affected by diverticular disease can bleed. This results in the passage of clots and sometimes a lot of fresh blood. These episodes can be dramatic but usually settle very quickly.
  • Stricture – Repeated episodes of inflammation of the bowel can result in a stricture or narrowing of the bowel. This can give symptoms similar to a partial blockage of the bowel.


Colonoscopy and CT scans are the commonest methods of detecting diverticular disease. They complement each other – colonoscopy can see inside the bowel and CT is particularly good at detecting thickening of the bowel wall and complications outside the bowel such as inflammation and abscesses.


Just because there are diverticula present does not mean that any treatment is required. General recommendations are to eat a high fibre diet and drink plenty of fluids (6-10 glasses daily) to prevent constipation. Some people find that fibre worsens discomfort – if so then a low fibre diet and a laxative such as Movicol/Laxido will usually be beneficial.

Acute diverticulitis is treated with antibiotics. Severe attacks and other complications require hospital admission. Where there are repeated episodes of inflammation, a stricture/narrowing of the bowel or significant daily symptoms from diverticular disease, surgery is an option to remove the abnormal section of the bowel. If you fall into this group then your Consultant will talk to you in detail about the risks and benefits of surgery.