The cause of diverticulosis is unknown but may be related to diet, a sedentary lifestyle, obesity, smoking, and use of certain drugs.
Spasms of the muscular layer of the intestine are thought to cause diverticula.
Diverticula usually cause no symptoms, but sometimes they become inflamed or bleed, causing blood in the stool or bleeding from the rectum.
Typically, the diagnosis is confirmed by colonoscopy or a computed tomography (CT) scan.
If people have symptoms, a high-fiber diet and stool-bulking agents are given, but sometimes bleeding occurs and requires colonoscopy or even surgery.
What Is Diverticulosis?
In diverticulosis, many balloon-like sacs (diverticula) develop in the large intestine, most commonly in the last part of it (sigmoid colon). Most diverticula vary in diameter from 1/10 inch to more than 1 inch (about ¼ centimeter to more than 2½ centimeters). For unclear reasons, some diverticula become very large—up to 6 inches (about 15 centimeters) in diameter.
(See also Definition of Diverticular Disease Definition of Diverticular Disease Diverticular disease is characterized by small, balloon-like sacs (diverticula) protruding through the layers of particular structures in the gastrointestinal tract (digestive tract). A single... read more .)
Diverticula in the large intestine Large Intestine The large intestine consists of the Cecum and ascending (right) colon Transverse colon Descending (left) colon Sigmoid colon (which is connected to the rectum) read more occur when a defect develops in the thick, muscular middle layer of the bowel. The thin inner layers of the bowel bulge out through the defect and create a small sac. Diverticula usually do not cause any problems but they sometimes become inflamed or bleed.
Diverticula may develop anywhere in the large intestine, but they are more common in the sigmoid colon, which is the last part of the large intestine just before the rectum. Diverticula vary in diameter from 1/10 inch to 1 inch (about ¼ to more than 2½ centimeters). They are uncommon before age 40 but become more common rapidly thereafter. Most people over age 80 have diverticula. Giant diverticula, which are rare, are larger than 1½ inches (about 4 centimeters) in diameter. A person may have only a single giant diverticulum.
Causes of Diverticulosis of the Large Intestine
The cause of diverticulosis is unknown but may be related to a diet low in fiber or high in red meat, a sedentary lifestyle, obesity, smoking, and use of nonsteroidal anti-inflammatory drugs Nonsteroidal Anti-Inflammatory Drugs Pain relievers (analgesics) are the main drugs used to treat pain. Doctors choose a pain reliever based on the type and duration of pain and on the drug's likely benefits and risks. Most pain... read more (NSAIDs), corticosteroids, or opioids Opioids Opioids are a class of drugs derived from the opium poppy (including synthetic variations) that are pain relievers with a high potential for misuse. Opioids are used to relieve pain, but they... read more . Other possible risk factors include family history and alterations in the structure of the large intestine and the way in which waste products move through it.
Diverticula are thought to be caused by spasms of the muscular layer of the intestine. The resulting pressure that these spasms exert on the intestinal wall causes a part of the wall to bulge at a point of weakness, usually near to where an artery penetrates the muscular layer of the large intestine. An increase in the thickness of the muscular layer is a common finding in the sigmoid colon of people with diverticulosis.
The cause of a giant diverticulum is unclear.
Symptoms of Diverticulosis of the Large Intestine
Diverticula themselves are not dangerous. In fact, most people with diverticulosis do not have symptoms. However, people with diverticulosis can sometimes have unexplained painful cramps or bowel movement disturbances (such as constipation).
Complications of diverticulosis
Complications of diverticulosis are more common in people who smoke, are obese, have HIV infection, take nonsteroidal anti-inflammatory drugs (NSAIDs), or are on cancer chemotherapy.
The most common complications are
Diverticulitis Diverticulitis Diverticulitis is inflammation of one or more balloon-like sacs (diverticula). Infection may or may not develop. Diverticulitis usually affects the large intestine (colon). Left lower abdominal... read more is inflammation with or without infection of a diverticulum, which causes abdominal pain and can result in a collection of pus (abscess) around the inflamed diverticulum. If a hole (perforation) develops in the diverticulum, fluid and bacteria can leak into the abdomen and cause a very serious condition called peritonitis Peritonitis Abdominal pain is common and often minor. Severe abdominal pain that comes on quickly, however, almost always indicates a significant problem. The pain may be the only sign of the need for surgery... read more .
A diverticulum can bleed into the intestine. Bleeding is painless but can be heavy and result in blood passing out through the rectum (see Gastrointestinal Bleeding Gastrointestinal Bleeding Bleeding may occur anywhere along the digestive (gastrointestinal [GI]) tract, from the mouth to the anus. Blood may be easily seen by the naked eye (overt), or blood may be present in amounts... read more ). Most episodes of bleeding stop spontaneously. However, in some people, doctors have to do endoscopy or surgery to stop the bleeding. The bleeding may be serious enough to require a blood transfusion.
Diagnosis of Diverticulosis of the Large Intestine
Colonoscopy or computed tomography (CT) scan
Diverticulosis is suspected when symptoms such as unexplained painful cramps, bowel movement disturbances, or painless rectal bleeding, especially in an older person, are present.
Diverticula that do not cause symptoms are usually found incidentally during colonoscopy Endoscopy Endoscopy is an examination of internal structures using a flexible viewing tube (endoscope). Endoscopy can also be used to treat many disorders because doctors are able to pass instruments... read more , video capsule endoscopy Video Capsule Endoscopy Video capsule endoscopy (wireless video endoscopy) is a procedure in which the person swallows a battery-powered capsule. The capsule contains one or two small cameras, a light, and a transmitter... read more , barium enema Barium x-ray studies of the digestive tract X-rays often are used to evaluate digestive problems. Standard x-rays (plain x-rays) do not require any special preparation ( see Plain X-Rays). These x-rays usually can show a blockage or paralysis... read more , CT scan Computed Tomography and Magnetic Resonance Imaging of the Digestive Tract Computed tomography (CT— see also Computed Tomography (CT)) and magnetic resonance imaging (MRI— see also Magnetic Resonance Imaging (MRI)) scans are good tools for assessing the size and location... read more , or magnetic resonance imaging (MRI Computed Tomography and Magnetic Resonance Imaging of the Digestive Tract Computed tomography (CT— see also Computed Tomography (CT)) and magnetic resonance imaging (MRI— see also Magnetic Resonance Imaging (MRI)) scans are good tools for assessing the size and location... read more ). The diagnosis of diverticulosis is usually confirmed by examining the large intestine using a flexible viewing tube (colonoscopy) or sometimes a CT scan of the abdomen. If the person has severe abdominal pain, doctors usually prefer CT so as not to rupture the inflamed intestine.
If blood is present in the stool, a colonoscopy is usually the best method with which to identify the source. However, in people who are bleeding a lot, CT angiography CT angiography In computed tomography (CT), which used to be called computed axial tomography (CAT), an x-ray source and x-ray detector rotate around a person. In modern scanners, the x-ray detector usually... read more or radionuclide scans Radionuclide Scanning In radionuclide scanning, radionuclides are used to produce images. A radionuclide is a radioactive form of an element, which means it is an unstable atom that becomes more stable by releasing... read more taken after radioactive red blood cells are injected into a vein (intravenously) may be required to determine the source of bleeding.
Treatment of Diverticulosis of the Large Intestine
No treatment for people who have no symptoms
Changes in diet for people who have symptoms
Treatment of bleeding
People who have diverticula but have no symptoms do not need treatment or changes to their diet.
The goal of treatment of diverticulosis in people who have symptoms is usually to reduce intestinal spasms, which is best achieved by maintaining a high-fiber diet (which consists of vegetables, fruits, and whole grains) and drinking plenty of fluids. Increased bulk in the large intestine reduces spasms, which in turn decreases the pressure on the walls of the large intestine. If a high-fiber diet alone is not effective, a diet supplemented daily with bran that does not dissolve in water and cannot be digested by the body or a bulking agent, such as psyllium or methylcellulose, may help. People who have constipation may also be given laxatives that increase bulk in the large intestine.
Most bleeding stops without treatment but if it does not, doctors often do colonoscopy to locate and clot (coagulate) the bleeding area with clips, heat, or a laser, or by injecting the area with a drug. Alternatively, doctors may do angiography to stop the bleeding. During this procedure, doctors pass a catheter into the artery that goes to the bleeding diverticulum and then inject material (a process called embolization) or the drug vasopressin to reduce blood flow to the bleeding diverticulum. Rarely, if bleeding recurs often or if the source of the bleeding cannot be determined, doctors may do surgery to remove some or all of the large intestine (a procedure called colectomy).
A giant diverticulum may require surgery because it is likely to become infected and rupture.