Abstract and Introduction
Colonic diverticula are common in developed countries and complications of colonic diverticulosis are responsible for a significant burden of disease. Several recent publications have called into question long-held beliefs about diverticular disease. Contrary to conventional wisdom, studies have not shown that a high-fiber diet protects against asymptomatic diverticulosis. The risk of developing diverticulitis among individuals with diverticulosis is lower than the 10% to 25% proportion that commonly is quoted, and may be as low as 1% over 11 years. Nuts and seeds do not increase the risk of diverticulitis or diverticular bleeding. It is unclear whether diverticulosis, absent diverticulitis, or overt colitis is responsible for chronic gastrointestinal symptoms or worse quality of life. The role of antibiotics in acute diverticulitis has been challenged by a large randomized trial that showed no benefit in selected patients. The decision to perform elective surgery should be made on a case-by-case basis and not routinely after a second episode of diverticulitis, when there has been a complication, or in young people. A colonoscopy should be performed to exclude colon cancer after an attack of acute diverticulitis but may not alter outcomes among individuals who have had a colonoscopy before the attack. Given these surprising findings, it is time to reconsider conventional wisdom about diverticular disease.
Colonic diverticulosis is extremely common in developed countries. In a consecutive series of 2000 barium enemas at the Massachusetts General Hospital, approximately two thirds of adults older than the age of 85 were found to have colonic diverticula. More recently, diverticulosis was found in 71% of colonoscopies in individuals older than the age of 80. Complications of colonic diverticula are responsible for a significant burden of disease. In 2009, diverticular disease was the sixth most frequent outpatient gastrointestinal diagnosis, with 2.6 million clinic visits. In that same year, diverticular disease was the most common in-patient gastrointestinal diagnosis in the United States with 283,355 hospitalizations at a cost of 2.7 billion dollars. Almost a quarter (22%) of patients admitted with diverticulitis underwent urgent or elective surgery for that condition.
Diverticula of the large bowel are out-pouchings in the wall of the colon at weak points in the circular muscle where blood vessels penetrate to supply the mucosa. Diverticula may be found throughout the colon, but are most common in the sigmoid colon where abnormalities include thickening and elastosis of the teniae, shortening of the bowel, and thickening and folding of the circular muscle. Diverticulosis most often is uncomplicated and asymptomatic. Complications may occur, including bleeding, abscess, perforation, fistula, stricture, or colitis. The term diverticular disease generally is used to denote diverticulosis with a complication.
Recent reports have challenged long-accepted dogma. For example, it is widely believed that diverticulosis is the result of a low-fiber diet. According to conventional wisdom, 10% to 25% of patients with colonic diverticula will develop diverticulitis during their lifetime. Diverticulosis is thought to be associated with chronic gastrointestinal symptoms in the absence of diverticulitis or overt colitis. Most physicians believe that diverticulitis is an infection and must be treated with antibiotics. Elective surgical resection of the affected colon has been recommended after a second attack of diverticulitis and after a first attack in young adults to reduce the risk of recurrence. Colonoscopy is suggested after an episode of acute diverticulitis to exclude colon cancer.
The goal of this article is to review recent publications that challenge conventional wisdom about diverticular disease.