Diverticulosis and Diverticulitis

People with diverticulosis have small pouches (called ‘diverticula’) protruding out of the wall of the colon or large intestine. It is thought that low dietary fiber leads to diverticulosis. Lack of vigorous exercise also seems to play a role in the development of diverticular disease, along with obesity. It makes sense, then, that diverticulosis is much more common in older people and in cultures where low-fiber diets, lack of exercise and obesity are part of the mainstream lifestyle.

In the United States, the prevalence is age-dependent, increasing from less than 5 percent at age 40, to 30 percent by age 60, to 65 percent by age 85. Westernized nations like the United States have prevalence rates of 5 to 45 percent while countries in Africa and Asia have a prevalence of 0.2 percent. The disease was first noticed in the United States around the time that processed foods (which were low in fiber) were introduced into the American diet.

Most experts believe that diverticular disease is caused by low-fiber diets. Constipation or hard stool, caused by a low-fiber diet, may cause people to strain when passing stool during a bowel movement. Straining may cause increased pressure in the colon, causing the colon lining to blow out through weak spots in the colon wall, thus causing diverticula.

Most people with diverticulosis never have any symptoms and their diverticula are identified while looking for other problems—for example, while screening people for colon cancer with routine colonoscopies. In fact, 70 percent of people with diverticulosis remain asymptomatic. Symptoms of diverticulosis are similar to those of irritable bowel syndrome and some experts believe that the two diseases co-exist in many patients. These symptoms include cramping, bloating, flatulence and irregular bowel movements.

The treatment of diverticulosis includes the addition of 20 to 35 grams of fiber to the diet, or, if that seems too difficult, the patient with diverticular disease could use fiber products such as Metamucil or Citrucel which provide 2 to 3.5 grams of fiber per dose. Many people believe that avoiding nuts, seeds, and popcorn is important in preventing these little food particles from entering the diverticula and causing irritation. However, experts do not agree that this approach is helpful.

Among all patients with diverticular disease, 15 to 25 percent develop diverticulitis—the condition of inflammation and infection of diverticula. The most common symptom of diverticulitis is abdominal pain—usually in the left lower corner. Common complaints are nausea, vomiting, fever, chills and a change in bowel habits. The treatment focuses on resting the colon, clearing up the inflammation and infection and minimizing complications. Mild cases may need only bed rest, oral antibiotics and a liquid diet, while severe cases require intravenous antibiotics in the hospital and sometimes surgery.

Five to 15 percent of patients develop diverticular bleeding. Diverticular bleeding is usually painless rectal bleeding which stops on its own. Abdominal pain is usually absent. About 5 percent of people with diverticular disease are initially diagnosed when they present with massive bleeding.

Dr. Kelly McMahon, a graduate of Yale University and the University of Pittsburgh School of Medicine, is board certified in Internal Medicine. She is a member of the American College of Physicians and the Allegheny County and Pennsylvania Medical Societies. She is in solo practice in the North Hills of Pittsburgh.