04/06/2009 - Articles

Diverticulosis or Diverticulitis ???

By: Robert W. Griffith, MD


Do you have diverticular disease? If so, do you have diverticulosis, or is it diverticulitis? Don't know? Read this article!


Doctors love long names, and as if diverticular disease wasn't enough, they bewilder us with diverticulosis and diverticulitis. The suffix --osis means a process or a condition, while the suffix --itis means inflammation. So the presence of small extrusions, (or sacs, or diverticula) from the inside of the colon is called diverticulosis. The lining of the colon and the loose tissue just under the lining layer squeezes out between the muscle layers of the large intestine wall.

At least 80% to 85% of patients with diverticulosis never have any symptoms. If clinical symptoms do occur in connection with diverticulosis (e.g. abdominal pain, change in bowel habit), but there are no signs of inflammation, the condition is called symptomatic diverticular disease, or painful diverticular disease. However, if there are signs of inflammation (e.g. fever, chills, tenderness to pressure, raised white blood cell count), the condition is called diverticulitis.

Who gets diverticulosis (and painful diverticular disease and diverticulitis)?

In the USA, about 30% of 50 to 70 year-olds will have diverticulosis. This increases to about 50% in 70 to 85 year-olds, and as much as 65% in the over-85s. Both men and women are equally affected.

As we have noted, 80% of people with diverticulosis never have any symptoms. Of those who do have symptoms, three-quarters have the less serious symptomatic diverticular disease, and one quarter have diverticulitis.

Diverticulosis is hardly known outside industrialized Western societies. However, this may change as dietary habits become more internationalized, with consumption of more highly processed foods and increased rates of obesity. It's been shown that it results from a low-residue diet, usually because of the removal of most of the fiber from flour and other foods. Low-residue intestinal contents mean the time spent in the colon increases, and the amount of stool is less. There is also likely to be more straining during defecation, raising the pressure inside the colon. All this increases the likelihood of diverticular formation.

Painful diverticular disease

Risk Factors: People who don't take much physical exercise are more likely to have painful diverticular disease. However, smoking, caffeine, and alcohol intake are not liable to increase the risk.

Symptoms: The attacks of abdominal pain that occur are usually colicky, but occasionally they may be steady. The pain can be provoked by eating, and relieved by passing wind or having a bowel movement. Constipation occurs in most cases, but some people have diarrhea. There can be some tenderness in the lower abdomen on the left side, and sometimes the doctor can feel a tender loop of distended colon.

Diagnosis: At one time, barium enema was the standard investigation done in such patients, but now colonoscopy is recommended, in order to exclude cancer, which may cause the same symptoms.

Management: Changing the diet is unlikely to reduce the presence of existing diverticula, but an increased fiber intake (bran, produce) will probably improve the symptoms. Moderate physical activity and preventing constipation with soluble fiber supplements (e.g. Metamucil®) should also help.


10% to 20% of people with diverticulosis may develop diverticulitis. It's caused by a tiny hole developing in a diverticulum, so that intestinal contents can leak out towards the peritoneal cavity. It's not been shown to be due to seeds lodging in a diverticulum. Usually, these tiny perforations are walled off by the tissues reacting to the inflammation, forming a small abscess that can eventually drain back into the inside of the colon. However, sometimes things can get more serious.

An abscess may form at the bottom of, or behind, the peritoneal cavity. Or there can be a generalized peritonitis, caused by rupture of an abscess. Sometimes there is a larger passage between the inside of the colon and the peritoneal cavity, allowing development of so-called fecal-peritonitis, a quite serious condition.

As the descending, or left part of the colon is usually involved, the clinical presentation has sometimes been called "left-sided appendicitis". If the ascending, or right part of the colon is the source of the trouble, it may be difficult for the doctor to distinguish the inflammation from a true appendicitis.

Symptoms: The pain of diverticulitis differs from that of painful diverticular disease -- it is usually starts suddenly, and it's persistent. There may be nausea, vomiting, loss of appetite, fever and chills. Constipation or diarrhea can occur. On pressure over the colon, there will probably be resistance to the pressure, with some pain when the pressure is released. Sometimes there is blood in the stool, so your physician will want to exclude the possibility of cancer of the colon. In elderly women, an ovarian cyst or ovarian tumor must be excluded.

Diagnosis: Regular x-rays of the abdomen will go a longway to helping the physician make the correct diagnosis. However, a computed tomography scan (CT scan) scan is helpful in making certain. An ultrasound exam is an alternative to CT.

Management: Very elderly patients with diverticulitis, or those who have a damaged immune system, should be hospitalized. If there are no complications, oral antibiotics and fluids-only by mouth are likely to be successful within 2-3 days.

In more serious diverticulitis, with CT scan showing complications, antibiotics and fluids must be given by intravenous infusion. Some cases will require surgery to remove the offending diverticulum and abscess. Nowadays, this can often be done successfully using a key-hole approach (laparoscopy).

Recurrences: The risk of recurrence after an attack of acute diverticulitis that has not been surgically treated ranges from 25% to 33%. Recurrences do not respond well to medical treatment, and are more serious. For that reason, surgery is recommended after two attacks of uncomplicated diverticulitis.


Diverticular disease is something that affects people more as they get older. It will probably affect more people in all parts of the world, as the low-residue diets so common in Western society become more popular worldwide. We hope that, in future, many people can avoid it, by adapting a suitable diet fairly early in their lifetime. Modern diagnostic approaches can help determine the correct diagnosis, and treatments are available to help patients through the two main disorders -- painful diverticular disease and diverticulitis.


Diverticular disease in the elderly. RJ. Farrell, JJ. Farrell, MM. Morrin, Gastroent Clin North Am , 2001, vol. 30, pp. 475--496


Created on: 05/15/2002
Reviewed on: 04/06/2009

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