INTRODUCTION
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 the presence of diverticula (diverticulosis), inflammation and/or infection of diverticula (diverticulitis), and bleeding from an artery within a diverticula (diverticular bleeding).
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, where the disease has become more common over time.
CAUSES
Environmental and lifestyle factors may have a role in the development of diverticular disease as a result of a low intake of dietary fiber. High fiber diets increase stool bulk, thereby decreasing the tension in the wall of 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.
SYMPTOMS
Diverticulosis is often found with 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. 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 tract between two organs that are not normally in communication with each other
- Obstruction a blockage of the colon
Less common complications include:
- Peritonitis infection involving the space around the abdominal organ
- Sepsis overwhelming bodywide infection that can lead to failure of multiple organs
Diverticular bleeding
Diverticular bleeding usually causes painless bleeding from the rectum. Up to 50 percent of patients note maroon or bright red blood with bowel movements.
It is not normal to see blood in a bowel movement; this can be a sign of several conditions, 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 are needed.
DIAGNOSIS
As mentioned above, diverticulosis is often found during tests performed for other reasons, such as routine screening for colon cancer and evaluation of abdominal pain or rectal bleeding. The following are tests that may be recommended to diagnose diverticulosis:
-
Barium enema: This is an x-ray study that uses barium in an enema to view the outline of the lower intestinal tract (
show radiograph 1
).
-
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 after the patient is given medication to induce sleep and prevent pain. (
See "Patient information: Colonoscopy"
).
-
CT scan Computer tomographic (CT) scanning is an imaging study that gives a two-dimensional picture of the abdomen in cross-section (
show radiograph 2
). It is the test most commonly used to diagnose diverticulitis and its complications.
-
Virtual colonoscopy Virtual colonoscopy is currently in development and may become useful in people who require colon cancer screening. This procedure uses CT scanning as air is introduced into the colon; a computer uses this data to generate a three-dimensional image of the lining of the colon (
show radiograph 3
). Preparation of the bowel (eg, with a laxative solution) is still required with virtual colonoscopy. (
See "Virtual colonoscopy"
).
TREATMENT
Diverticulosis
People with diverticular disease who do not have symptoms do not require specific treatment. However, most clinicians recommend fiber supplements, which can help to bulk the stools and possibly prevent the development of new diverticula, diverticulitis, or diverticular bleeding. However, fiber is not proven to prevent these conditions.
Increase fiber
By reading the product information panel on the side of the package, the fiber content can be calculated (
show figure 1
). Fruits and vegetables are a good source of fiber and can be particularly helpful in preventing and/or treating constipation (
show table 1A-2C
). This is especially true of citrus fruits, prunes, and prune juice.
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 the undigested fragments could become lodged within a diverticulum, thereby inciting an episode of diverticulitis. However, this belief is completely unproven.
Diverticulitis
Treatment of diverticulitis depends upon the severity of symptoms and clinical findings.
Home treatment
Patients with mild symptoms can be treated at home with a clear liquid diet and oral antibiotics. However, it is important to understand the signs or symptoms that require immediate medical attention during treatment at home, including an increase in fever or abdominal pain or an inability to consume adequate fluids.
Hospital treatment
Patients with moderate to severe symptoms sometimes require hospitalization. During this time, the person is not allowed to eat or drink; antibiotics and fluids are given into a vein. Patients who develop an abscess or blockage of the colon may require drainage of the abscess (usually performed by placing a drainage tube through the abdomen, vagina, or rectum) or by surgically opening the affected area.
Emergency surgery
Patients who develop a generalized infection in the abdomen (peritonitis) usually require emergency surgery. A two-part surgery may be necessary in some cases.
- The first surgery involves removal of the diseased colon and creation of a colostomy, which is an opening between the colon and the skin. The lower end of the colon is temporarily sewed closed to allow it to heal.
- Approximately three months later, a second surgery is performed to reconnect the two parts of the colon and close the skin.
In non-emergency situations, removal of the diseased area of the colon and reconnection of the two ends is done in one surgery.
After diverticulitis resolves
After resolution of an episode of diverticulitis, full evaluation of the colon with colonoscopy, barium enema, or both is recommended to establish the extent of disease and to rule out the presence of co-existing lesions such as polyps or cancer. (
See "Patient information: Colon polyps"
and
see "Patient information: Screening for colon cancer"
).
Diverticular bleeding
Most cases of diverticular bleeding resolve on their own. However, some patients require evaluation or treatment to stop bleeding, which may include a colonoscopy, angiography (in which the source of bleeding is treated by blocking off the bleeding artery), or surgery.
PROGNOSIS
Diverticulosis
Diverticulosis may cause no future problems or may cause future episodes of bleeding and/or diverticulitis. 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 while about 15 percent of patients 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 following a second attack of diverticulitis; the rate of complications in this group is close to 60 percent. Only 10 percent of patients remain asymptomatic after a second attack.
Surgery versus medical therapy
Surgery to remove disease area of the colon may not be necessary for people who improve with medical therapy. However, patients who are treated with surgery are felt to be cured since only 15 percent of patients develop diverticulosis in the remaining colon and only 2 to 11 percent of patients need further surgery.
Thus, surgery may be recommended for people with repeated attacks of diverticulitis or if there are severe or repeated episodes of 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 in people who are less than 40 to 50 years, although this is controversial. In this age group, the disease may be more severe and there may be an increased risk of recurrent disease that will ultimately require surgery.
In many cases, an elective operation can be performed laparoscopically, using small incisions, rather than the typical vertical abdominal incision. Laparoscopic surgery usually allows the person to recover faster and avoid a longer hospital stay.