As we age, most of us develop small pouches (diverticula) that bulge outward through weak points in the wall of the large intestine—a condition called diverticulosis. The condition is present in about half of Americans over age 60. A disorder called diverticulitis, an infection or inflammation of diverticula, develops in about 10 to 25 percent of people with diverticulosis. Diverticulosis and diverticulitis are referred to as diverticular disease.
Although diverticulosis can occur anywhere along the length of the colon, the pouches typically develop in the sigmoid colon, the last portion of the colon before the rectum. The number of diverticula can range from one (called a diverticulum) to hundreds. Diverticula are usually 5 to 10 mm in diameter but can exceed 2 cm.
Causes of diverticulosis and diverticulitis
A low-fiber diet is the major culprit in diverticulosis because it leads to hard stools. When you strain to move hardened stool, pressure inside the colon increases, which can cause weak spots in the colon wall to bulge outward and become diverticula. Diverticulosis primarily affects people in affluent, industrialized areas like the United States, Europe, and Australia, where diets low in fiber are common.
Diverticulitis occurs when bacteria or hardened stool is trapped in a diverticulum, causing an infection or inflammation. This may ultimately lead to a small hole in the tip of a diverticulum, which allows bacteria to enter the abdomen and cause infection (peritonitis).
Symptoms of diverticulosis and diverticulitis
Although most people with diverticulosis have no discomfort or symptoms, some experience mild abdominal pain, bloating, and constipation. The pain typically occurs in the lower abdomen, most often on the left side. This area of the abdomen may feel full or tender when touched. The pain can be severe and fluctuate in intensity and may also occur with
- change in bowel habits
- painful or difficult urination
- increased frequency of urination
The severity of the symptoms depends whether the infection has spread beyond the colon and whether any complications such as a perforation have occurred. Rarely, people with diverticulosis experience mild, painless bleeding from the rectum, which occurs when a small blood vessel adjacent to the diverticulum ruptures. The bleeding usually stops on its own. If it persists or recurs, therapeutic endoscopy may be needed. If bleeding persists, surgery to remove the portion of the colon containing the bleeding diverticulum may be necessary.
Diagnosis of diverticulosis and diverticulitis
Diverticulosis is often discovered by accident during an exam, such as a barium enema, sigmoidoscopy, or colonoscopy, for another gastrointestinal ailment. If you have symptoms and your medical history and examination suggest diverticular disease, your doctor will do one or more tests.
A barium enema or CT scan can diagnose diverticular disease and its complications. Your doctor may also recommend a colonoscopy to check whether cancer is causing the symptoms.
Treatment of diverticulosis and diverticulitis
For most people with diverticulosis, eating a high-fiber diet will relieve symptoms and prevent the development of diverticulitis. Diverticulitis is usually treated at home with bed rest, a liquid diet to rest the colon, and oral antibiotics. People with severe diverticulitis may be hospitalized and treated with intravenous antibiotics.
Most people with severe diverticulitis, however, can be treated successfully without surgery. If antibiotics do not eradicate the infection associated with diverticulitis, an abscess (a collection of pus surrounded by inflamed tissue) may form in the abdominal cavity adjacent to the colon. The abscess can be treated with more antibiotics or it may need to be drained by inserting a needle into the abscess through the skin and draining the infected fluid through a catheter.
Surgical treatment is necessary in some people with a resistant infection. Rarely, the infection may leak out of an abscess and spread into the abdominal cavity, causing a condition called peritonitis. In such cases, surgery is required immediately to clean the abdominal cavity and remove the damaged region of the colon.
A fistula (an abnormal connection between two organs) can form when an abscess erodes, creating a passage between the colon and an adjacent organ such as the bladder, small intestine, vagina, or skin. The most common type of fistula connects the colon and the bladder.
This abnormality, which occurs far more often in men than in women, can lead to severe, persistent urinary tract infections. Surgery to remove the fistula and the affected part of the colon is needed to correct the problem.