Diverticular Disease


WHAT IS DIVERTICULAR DISEASE? — A diverticulum is a sac-like protrusion that sometimes forms in the muscular wall of the colon, particularly at points where blood vessels enter. Diverticular disease of the colon refers to diverticulosis, diverticulitis, and diverticular bleeding.

  • Diverticulosis means that diverticula are present within the colon.
  • Diverticulitis refers to infection of diverticula.
  • Diverticular bleeding refers to bleeding from an artery located within a diverticulum.


WHAT CAUSES DIVERTICULAR DISEASE? — Diverticular disease is a common problem that affects men and women equally. The risk of disease increases with age. It occurs throughout the world but is seen more commonly in developed countries, in which the incidence has increased over time. This suggests that environmental and lifestyle factors may have a role in the development of this disease. One factor may be low intake of dietary fiber. High fiber diets increase stool bulk thereby decreasing the wall tension in the colon. High wall tension is thought to increase the risk of developing diverticula.

Diverticulitis — Inflammation of a diverticulum (diverticulitis) occurs as a result of erosion of the diverticular wall due to increased colonic wall tension or hardened particles of stool, which can become lodged within the diverticulum. Both of these events probably decrease blood flow to the diverticulum.

Diverticular bleeding — Diverticular bleeding occurs when a small artery located within the diverticulum erodes into the colon.


WHAT ARE THE SYMPTOMS OF DIVERTICULAR DISEASE? — Diverticulosis is often an incidental finding at the time of a test done for other reasons, such as flexible sigmoidoscopy, colonoscopy, or barium enema. Most people with diverticulosis have no symptoms and will remain symptom free for the rest of their lives. On the other hand, about 15 to 25 percent of people will develop diverticulitis while 5 to 15 percent will develop diverticular bleeding.

Diverticulitis — The symptoms of diverticulitis depend upon the degree of inflammation present. The most common symptom is pain in the left lower abdomen. Other possible symptoms include nausea and vomiting, constipation, diarrhea, and urinary symptoms.

Diverticulitis is divided into simple and complicated forms. Simple diverticulitis, which accounts for 75 percent of cases, is not associated with complications and typically responds to medical treatment without surgery. Complicated diverticulitis occurs in 25 percent of cases and usually requires surgery. The most common complications associated with diverticulitis include the following:

  • Abscess — a localized collection of pus
  • Fistula — an abnormal track between two organs that are not normally in communication with each other
  • Obstruction — a blockage of the colon

Diverticular bleeding — Diverticular bleeding is most often painless bleeding through the rectum. Abdominal discomfort is usually not present, and it is rare for bleeding to coexist with acute diverticulitis. Approximately 5 percent of patients with diverticulosis present with massive bleeding. The majority of these patients are over 60 years of age and many have coexisting medical conditions.

HOW IS DIVERTICULAR DISEASE DIAGNOSED? — As mentioned above, diverticulosis is often found during tests done for other reasons, such as routine screening for colon cancer and evaluation for abdominal pain or rectal bleeding. The following are the ways by which diverticulosis is diagnosed:

  • Barium enema: This is an x-ray study where barium is administered in an enema to make it possible to obtain a picture of the lower intestinal tract.
  • Flexible sigmoidoscopy: This is a visual examination of the inner surface of the sigmoid colon, made by insertion of a thin, flexible tube that contains a lens to permit the doctor to view the intestines.
  • Colonoscopy: This is a visual examination of the inner surface of the entire colon, conducted in the same manner as a flexible sigmoidoscopy. A colonoscopy is usually performed under sedation, however.
  • CT scan: Computer tomographic (CT) scanning is an imaging study that gives a two-dimensional picture of the abdomen in cross-section. It is the test most commonly used to diagnose diverticulitis and its complications.



Diverticulosis — Patients with diverticular disease who do not have any symptoms do not require specific treatment. However, most doctors recommend fiber supplementation, which can help to bulk the stools and thereby possibly help prevent the development of new diverticula, diverticulitis, or diverticular bleeding, although this has not been proven.

Diverticulitis — Treatment of diverticulitis depends upon the severity of symptoms and clinical findings.

  • Patients with mild symptoms can be treated as outpatients with a clear liquid diet and with oral antibiotics.
  • Patients with moderate to severe symptoms may require hospitalization during which they are kept fasting while being given intravenous fluids and antibiotics. Patients who develop an abscess or obstruction may require drainage of the abscess or surgery.

After resolution of an episode of diverticulitis, the colon requires full evaluation by colonoscopy, barium enema, or both to establish the extent of disease and to rule out the presence of co-existing lesions such as polyps or cancer.

Diverticular bleeding — Most cases of diverticular bleeding resolve on their own. However, some patients require interventions, which may include a colonoscopy, angiography (in which the source of bleeding is treated by blocking off the bleeding artery), or surgery.


Diverticulosis — Diverticulosis may remain quiescent or may manifest itself in the form of bleeding and/or diverticulitis over time. As mentioned above, about 15 to 25 percent of people will develop diverticulitis while 5 to 15 percent will develop diverticular bleeding.

Diverticulitis — Approximately 85 percent of patients with uncomplicated diverticulitis will respond to medical treatment; 15 percent will need surgery. After successful therapy for a first attack of diverticulitis, one-third of patients will remain asymptomatic, one-third will have episodic cramps without diverticulitis, and one-third will go on to have a second attack of diverticulitis.

The prognosis is worse with a second attack of diverticulitis with the rate of complications approaching 60 percent. Only 10 percent of patients remain asymptomatic after recovering with medical therapy from a second attack.

Elective surgery to remove the section of the colon that contains the diverticula is not necessary for all patients who respond to medical therapy. On the other hand, patients who are treated with surgery are felt to be cured since diverticulosis develops in the remaining colon in only 15 percent of patients and only 2 to 11 percent of patients need further surgery. As a result, surgery may be recommended for patients with repeated attacks of diverticulitis or those with severe or repeated bleeding. The decision depends in part upon the patient's other medical conditions and suitability for surgery. Some doctors recommend surgery after the first attack of diverticulitis for patients who are under age 40 to 50, although this is controversial. The rationale for this recommendation is that the disease may be more severe in younger patients and that they are at increased risk for recurrent disease that will ultimately require surgery.