A diverticulum is a pouch-like structure that can form through points of weakness in the muscular wall of the colon (ie, at points where blood vessels pass through the wall).

Diverticulosis affects men and women equally. The risk of diverticular disease increases with age. It occurs throughout the world but is seen more commonly in developed countries.


Diverticulosis — Diverticulosis merely describes the presence of diverticula. Diverticulosis is often found during 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.

A person with diverticulosis may have diverticulitis, or diverticular bleeding.

Diverticulitis — Inflammation of a diverticulum (diverticulitis) occurs when there is thinning and breakdown of the diverticular wall. This may be caused by increased pressure within the colon or by hardened particles of stool, which can become lodged within the diverticulum.

The symptoms of diverticulitis depend upon the degree of inflammation present. The most common symptom is pain in the left lower abdomen. Other symptoms can include nausea and vomiting, constipation, diarrhea, and urinary symptoms such as pain or burning when urinating or the frequent need to urinate.

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. Complications associated with diverticulitis can include the following:

•Abscess – a localized collection of pus

•Fistula – an abnormal tract between two areas that are not normally connected (eg, bowel and bladder)

•Obstruction – a blockage of the colon

•Peritonitis – infection involving the space around the abdominal organ

•Sepsis – overwhelming body-wide infection that can lead to failure of multiple organs

Diverticular bleeding — Diverticular bleeding occurs when a small artery located within a diverticulum is eroded and bleeds into the colon.

Diverticular bleeding usually causes painless bleeding from the rectum. In approximately 50 percent of cases, the person will see maroon or bright red blood with bowel movements.

Is bleeding with a bowel movement normal? — It is not normal to see blood in a bowel movement; this can be a sign of several conditions, most of which are not serious (eg, hemorrhoids) but some of which are serious and require immediate treatment. Anyone who sees blood after a bowel movement should consult with their healthcare provider to determine if further testing or evaluation is needed.


Diverticulosis is often found during tests performed for other reasons.

●Barium enema – This is an x-ray study that uses barium in an enema to view the outline of the lower intestinal tract. This is an older test and has been largely replaced by computed tomography (CT) scan.

●Flexible sigmoidoscopy – This is an examination of the inside of the sigmoid colon with a thin, flexible tube that contains a camera.

●Colonoscopy – This is an examination of the inside of the entire colon.

●CT scan – A CT scan is used often to diagnose diverticulitis and its complications. If diverticulitis (not just diverticulosis) is suspected, the above three tests should not be used because of the risk of perforation.


Diverticulosis — People with diverticulosis who do not have symptoms do not require treatment. However, most clinicians recommend increasing fiber in the diet, which can help to bulk the stools and possibly prevent the development of new diverticula, diverticulitis, or diverticular bleeding. Fiber is not proven to prevent these conditions in all patients but may help to control recurrent episodes in some.

Increase fiber — Fruits and vegetables are a good source of fiber. The fiber content of packaged foods can be calculated by reading the nutrition label.

Seeds and nuts — Patients with diverticular disease have historically been advised to avoid whole pieces of fiber (such as seeds, corn, and nuts) because of concern that these foods could cause an episode of diverticulitis. However, this belief is completely unproven. We do not suggest that patients with diverticulosis avoid seeds, corn, or nuts.

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Diverticulitis — Treatment of diverticulitis depends upon how severe your symptoms are.

Home treatment — If you have mild symptoms of diverticulitis (mild abdominal pain, usually left lower abdomen), you can be treated at home with a clear liquid diet and oral antibiotics. However, if you develop one or more of the following signs or symptoms, you should seek immediate medical attention:

●Temperature >100.1°F (38°C)

●Worsening or severe abdominal pain

●Inability to tolerate fluids

Hospital treatment — If you have moderate to severe symptoms, you may be hospitalized for treatment. During this time, you are not allowed to eat or drink; antibiotics and fluids are given into a vein.

If you develop an abscess of the colon, you may require drainage of the abscess (usually performed by placing a drainage tube across the abdominal wall under radiologic guidance) or by surgically opening the affected area.

Surgery — If you develop a generalized infection in the abdomen (peritonitis), you will usually require an emergency operation. A two-part operation may be necessary in some cases.

●The first operation involves removal of the diseased colon and creation of a colostomy. A colostomy is an opening between the colon and the skin, where a bag is attached to collect waste from the intestine. The lower end of the colon is temporarily sewed closed to allow it to heal.

●Approximately three to six months later, a second operation is performed to reconnect the two parts of the colon and close the opening in the skin. You are then able to empty your bowels through the rectum. Sometimes patients require up to a year to recover from the first operation, depending on how sick they were.

In non-emergency situations, the diseased area of the colon can be removed and the two ends of the colon can be reconnected in one operation, without the need for a colostomy.

Surgery versus medical therapy — An operation to remove the diseased area of the colon may be necessary if you do not improve with medical therapy. After an episode of uncomplicated diverticulitis, elective surgery is generally not required as the risk of another attack or requiring emergency surgery is low. However, patients with persistent symptoms attributable to diverticulitis, a history of complicated diverticulitis, or a compromised immune system should be evaluated for possible surgery to prevent another attack. In such patients, another attack has been associated with a higher risk of complications or death. Of course, the decision will also depend in part upon your other medical conditions and ability to undergo surgery.

In many cases, an elective operation can be performed laparoscopically, using small incisions, rather than the typical vertical (up and down) abdominal incision. Laparoscopic surgery usually allows you to recover more quickly and shortens the hospital stay.

After diverticulitis resolves — After an episode of diverticulitis resolves, if you have not had a recent colonoscopy, the entire length of the colon should be evaluated to determine the extent of disease and to rule out the presence of abnormal lesions such as polyps or cancer. Recommended tests include one of the following: colonoscopy, barium enema and sigmoidoscopy, or CT colonography to rule out concomitant disease.

Diverticular bleeding — Most cases of diverticular bleeding resolve on their own. However, some people will need further testing or treatment to stop bleeding, which may include a colonoscopy, angiography (a treatment that blocks off the bleeding artery), bleeding scan, or surgery.


Diverticulosis — Over time, diverticulosis may cause no problems or it may cause episodes of bleeding and/or diverticulitis. Approximately 15 to 25 percent of people with diverticulosis will develop diverticulitis, while 5 to 15 percent will develop diverticular bleeding.

Diverticulitis — Approximately 85 percent of people with uncomplicated diverticulitis will respond to medical treatment, while approximately 15 percent of patients will need an operation. After successful treatment 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 tends to remain similar following a second attack of diverticulitis. Only 10 percent of people remain symptom-free after a second attack. Subsequent attacks tend to be of similar severity, not increasing in severity as previously believed.