A diverticulum is an outward protrusion of a weakened organ wall, as seen in the colon, bladder or esophagus. The sigmoid colon is the last section of the colon, and it is approximately 40 cm long. In order to eliminate waste, the sigmoid colon has to contract. Such contraction results in colon lumen narrowing at both ends and pressure increase, which is amplified by voluntary straining of the pelvic muscles. The main causes of colonic diverticular disease, or CDD, are chronically increased sigmoid colon pressure and abnormal colonic contractions.
Diverticular Disease
Chronic diverticular disease includes diverticulosis or the presence of multiple diverticula, and diverticulitis or diverticular inflammation. The UpToDate review of multiple studies concludes that CDD is exceedingly common in the western world and rare in undeveloped countries, suggesting that lifestyle habits, such as poor diet and lack of exercise, are responsible for CDD. Men and women are affected equally. Symptoms of CDD are the result of associated complications such as infection or diverticular perforation. The most common symptoms are left-sided abdominal pain and large, painless rectal bleeding.
Diet
According to the UpToDate review, chronic diverticular disease is common in people who consume red meat and fatty diet with low amounts of vegetables and fruits, which provide dietary fiber. Vegetarians rarely have CDD, compared to non-vegetarians. Dietary fiber acts as a bulking agent in the colon, reducing the narrowing at sigmoid ends during a contraction. This, in turn, reduces the pressure exerted on the colonic wall.
Physical Activity and Obesity
The journal "Medicine and Science in Sports and Exercise" reports that running and jogging significantly reduce the risk of colonic diverticular disease and its symptoms. In addition, the journal "Gastroenterology" reports that lack of physical exercise and obesity, specifically body-mass-index, waist-to-hip ratio and waist circumference, cause a markedly increased risk of CDD, diverticulitis and diverticular bleeding.
Colon Cancer
There is a significant risk of sigmoid colon cancer in patients with chronic diverticular disease, states the journal "Gut." This is likely due to high concentrations of bacteria in the sigmoid colon that produce cancer-causing chemicals and the trapping of bacteria in diverticula, which causes colon wall irritation and chronic diverticulitis.
Diverticulitis
Diverticulitis is caused by erosion of a diverticular wall due to high colonic pressure or food particles lodged in a diverticulum. Inflammation, a body's response to injury, eventually leads to focal tissue death and diverticular perforation. Small diverticular perforation can be effectively contained by the body's immune system, causing mild or no symptoms. However, large perforation often results in a localized abscess, colonic obstruction or abnormal connection between the colon and another organ. In extreme cases, non-contained perforation may result in inflammation and infection of the peritoneum, a membrane that lines the entire abdominal cavity, resulting in peritonitis.
Diverticular Bleeding
Diverticular bleeding is the most common source of lower gastrointestinal bleeding. It is caused by a small artery in the diverticulum. Substantial and painless rectal bleeding resolves spontaneously in 80 percent of patients, according to the "American Family Physician." Surgery is rarely necessary due to effective medical management techniques to stop the bleeding. In extreme cases, when bleeding cannot be stopped, removing parts of the colon or an entire colon may be required.
References
- "Gastroenterology"; Obesity Increases the Risks of Diverticulitis and Diverticular Bleeding; Lisa Strate M.D., et al.; January 2009
- "Gut"; Increased Risk of Left Sided Colon Cancer in Patients with Diverticular Disease; T. Stefansson M.D., et al.; April 1993
- "Medicine and Science in Sports and Exercise"; Incident Diverticular Disease is Inversely Related to Vigorous Physical Activity; Paul Williams; May 2009
- "American Family Physician"; Diverticular Bleeding; Thad Wilkins M.D., et al.; November 2009
- UpToDate; Epidemiology and Pathophysiology of CDD; Tonia Young-Fadok M.D. at al.; May 2010
