Many people have small pouches in the lining of the colon, or large intestine, that bulge outward through weak spots. Each pouch is called a diverticulum. Multiple pouches are called diverticula. The condition of having diverticula is called diverticulosis. Diverticula are most common in the lower portion of the large intestine, called the sigmoid colon. When the pouches become inflamed, the condition is called diverticulitis. Diverticulosis and diverticulitis together are called diverticular disease.
About 10 percent of North Americans older than 40 have diverticulosis. The condition becomes more common as people age. About half of all people older than 60 have diverticulosis. Ten to 25 percent of people with diverticulosis get diverticulitis. Diverticular disease is common in developed or industrialized countries.
Although not proven, the dominant theory is that a low-fiber diet causes diverticular disease. Fiber is the part of fruits, vegetables, and grains that the body cannot digest. Fiber help prevent constipation by making stools soft and easy to pass. Constipation or hard stool may cause people to strain when passing stool during a bowel movement. Straining may cause increased pressure in the colon, which may cause the colon lining to bulge out through weak spots in the colon wall.
Doctors are not certain what causes diverticula to become inflamed. The inflammation may begin when bacteria or stool are caught in the diverticula.
Most people with diverticulosis do not have any discomfort or symptoms. However, some people may experience:
Other conditions such as irritable bowel syndrome and stomach ulcers cause similar problems, so the symptoms do not always mean a person has diverticulosis. People with chronic symptoms should visit their doctor or health care provider.
Increasing the amount of fiber in the diet may reduce symptoms of diverticulosis and prevent complications such as diverticulitis. Consuming 20 to 35 grams of fiber each day is recommended. The doctor may also recommend taking a fiber product such as methylcellulose (Citrucel) or psyllium (Metamucil) one to three times a day. These products are available in powder, pills, or wafers, and provide 2 to 3.5 grams of fiber per dose. Fiber products should be taken with at least 8 ounces of water.
If cramps, bloating, and constipation are problems, the doctor may prescribe a short course of pain medication. However, some pain medications actually cause constipation.
The most common symptom of diverticulitis is abdominal pain. The most common sign on examination is tenderness in the lower left side of the abdomen. Usually, the pain is severe and comes on suddenly, but it can also be mild and become worse over several days. The intensity of the pain can fluctuate. A person may experience:
Diverticulitis can lead to complications that require treatment to prevent them from progressing and causing serious illness. These include:
Bleeding - Rectal bleeding from diverticula is a rare complication. When diverticula bleed, blood may appear in the toilet or in the stool. Bleeding can be severe, but it may stop by itself and not require treatment. If the bleeding does not stop, surgery may be necessary to remove the involved portion of the colon.
Abscess, Perforation, and Peritonitis - Diverticulitis may lead to infection, which often clears up after a few days of treatment with antibiotics. If the infection gets worse, an abscess may form in the wall of the colon. If the abscess is small and remains in the wall of the colon, it may clear up after treatment with antibiotics. If the abscess does not clear up with antibiotics, the doctor may need to drain it using a catheter placed into the abscess through the skin.
Infected diverticula may develop perforations. Sometimes the perforations leak pus out of the colon and form a large abscess in the abdominal cavity, a condition called peritonitis. A person with peritonitis may be extremely ill with nausea, vomiting, fever, and severe abdominal tenderness. The condition requires immediate surgery to clean the abdominal cavity and remove the damaged part of the colon. Without prompt treatment, peritonitis can be fatal.
Fistula - A fistula is an abnormal connection of tissue between two organs or between an organ and the skin. When diverticulitis-related infection spreads outside the colon, the colon’s tissue may stick to nearby tissues. The most common type of fistula occurs between the bladder and the colon. This type of fistula affects men more often than women. It can result in a severe, long-lasting infection of the urinary tract. The problem can be corrected with surgery to remove the fistula and the affected part of the colon.
Intestinal Obstruction - Scarring caused by infection may lead to partial or total blockage of the intestine. When the intestine is blocked, the colon is unable to move bowel contents normally. If the intestine is completely blocked, emergency surgery is necessary. Partial blockage is not an emergency, so the surgery to correct it can be planned.
Uncomplicated diverticulitis with mild symptoms usually requires the person to rest, take oral antibiotics, and be on a liquid diet for a period of time. Sometimes an attack of diverticulitis is serious enough to require a hospital stay, intravenous (IV) antibiotics, and possibly surgery.
Treatment for diverticulitis focuses on clearing up the inflammation and infection, resting the colon, and preventing or minimizing complications. Depending on the severity of symptoms, the doctor may recommend bed rest, oral antibiotics, a pain reliever, and a liquid diet. If symptoms ease after a few days, the doctor will recommend gradually increasing the amount of high-fiber foods in the diet. Severe cases of diverticulitis with acute pain and complications will likely require a hospital stay. Most cases of severe diverticulitis are treated with IV antibiotics and a few days without food or drink to help the colon rest. In some cases, surgery may be necessary.