Diverticulosis is an extremely common condition characterized by the presence of small outpouchings (diverticulae) of the wall of the large intestine (colon). In North America, 50% of people over the age of 50 have some diverticulosis of the colon (diverticulosis of the small intestine is extremely uncommon). Diverticulae occur most frequently in the lower part of the colon known as the sigmoid colon, however, other parts of the colon may also be involved.

What causes diverticular disease?

The exact cause of diverticulosis is not known. The condition becomes more prevalent with age and it appears to run in families. The low fibre North American diet is thought to be a major factor as the disease is much less prevalent in underdeveloped countries where highly refined food products are unavailable. When there is inadequate bulk in the bowel, the bowel tends to become irritable and spastic. When segments of the colon go into spasm, the areas between the spasms may be subjected to very high pressures, causing small areas of the colon to bulge out. Over time, these bulges develop into permanent little pouches.

Can I prevent diverticular disease?

Perhaps. The best preventative would seem to be a good diet with a high fibre content. Daily bran in some form, adequate root vegetables, and fresh fruit provide excellent fibre. Proper activity and avoidance of constipation may also be of benefit. It has never been shown that colonic hydrotherapy (a fancy term for an enema) can prevent diverticular disease (or anything else for that matter!). Enemas can be dangerous, particularly if there is an abnormality of the colon. In patients with diverticulitis, an enema may lead to worsening of the perforation and the requirement for surgical treatment.

Explaining diverticulosis versus diverticulitis

Diverticulosis simply means having diverticuli. Having diverticulitis means that one of those diverticuli is inflamed. Why a diverticulum or group of diverticulae will become inflamed is not well known but the fact that it does not happen more often is surprising since these little pouches are often filled with hard stool, bacteria, seeds, or other food items. If they do become irritated, local inflammation can develop. This may lead to increased colon spasms, swelling and partial obstruction of the colon, and even frank perforation of the diverticulum with leakage of feces and gas into the abdominal cavity. Some specialists feel that most cases of diverticulitis arise from a microperforation of a diverticulum that then progresses to a larger problem as the leaking stool leads to an abscess.

Does diverticulosis cause cancer?

No. Diverticular disease of the bowel does not cause cancer. However, cancer symptoms may be similar to symptoms of diverticulosis, and both conditions occur in similar age groups. So it is important that the initial diagnosis is accurate and that the diagnosis be regularly "revisited" (re-established) to ensure that one does not miss the development of a bowel cancer under the false impression that symptoms are just another attack of the "same old diverticulitis." If the diverticular segment cannot be carefully assessed by colonoscopy in order to ensure there is no simultaneous colon cancer in that segment, it may be best to remove it in order to eliminate the "blind spot." Persistence of symptoms, or new, or different symptoms should be reported to the doctor. Rectal bleeding, weight loss, and chronic pain should be fully investigated.

Michael E. Pezim, MD 
in association with the MediResource Clinical Team