Diverticulosis and diverticulitis are conditions of civilization and aging. As such, they are becoming more frequent. Get up to date with this review...

Introduction

The presence of one or more extrusions, or sacs, from the lumen of the colon is termed diverticulosis. The lesions consist of mucosa and submucosa sacs extruding between the muscle layers in the colon wall. At least 80% to 85% of patients with diverticulosis never have any symptoms. If clinical symptoms are associated with diverticula (abdominal pain, change in bowel habit), but there are no signs of inflammation, the condition is called symptomatic diverticular disease (or painful diverticular disease). If signs and symptoms of inflammation are present (fever, leukocytosis, or peritoneal signs), the condition becomes diverticulitis.

Prevalence

The prevalence of diverticular disease increases with age -- e.g. 30% in 50-70 year-olds, 50% in 70-85, and 65% in over-85 year-olds. While the sexes are equally affected, there are ethnic differences. The condition is hardly known outside industrialized Western societies. However, this may change as dietary habits become globalized, with consumption of more highly processed foods and increased prevalence of obesity. Ethnic differences in the anatomical distribution of diverticula in the colon are probably genetic, rather than environmental.

Pathogenesis

Diverticular disease is a disease of industrialization -- it results from a low-residue diet, usually because of the removal of most of the fiber from flour and other foods. Low-residue intestinal contents results in prolonged colonic transit time, decreased stool volume, and increased intraluminal pressure at defecation.

Symptomatic diverticular disease

Of those who have symptoms from their diverticula, about 75% have this condition, i.e. there is absence of an inflammatory component. Attacks of abdominal pain occur, which are usually colicky, but occasionally steady. The pain can be provoked by eating, and relieved by passing flatus or a bowel movement. Constipation occurs in 2/3 of cases, but diarrhea is also seen. There can be tenderness in the left lower quadrant, and sometimes a tender, palpable loop of distended sigmoid colon.

Tests show that people with symptomatic diverticular disease have increased colonic motility and increased colonic intraluminal pressure, compared with asymptomatic diverticulosis subjects. A risk factor appears to be lack of physical activity, whereas smoking, caffeine, and alcohol intake are not associated with an increased prevalence.

Diagnosis: Barium enema used to be the standard investigation done in such patients, but although it can demonstrate diverticula, it cannot determine their clinical significance. Routine colonoscopy is recommended in people with painful diverticular disease, in order to exclude neoplasia. This should be done with some care, in case the air insufflation disrupts an undiagnosed diverticulitis, which may have a micro-perforation.

Management: It is unlikely that existing diverticula will regress with a change in diet; however, an increased fiber intake (bran, produce) is likely to improve symptoms. Moderate physical activity and management of constipation with soluble fiber supplements can also be of benefit.

Diverticulitis

This condition is likely to occur in 10% to 20% of people with diverticula. It is preceded by micro-perforation of one or more diverticula, possibly as the result of persistent high intraluminary pressure. Lodging of seeds or fecoliths in a diverticular sac has not been proven as a cause of diverticulitis. Usually, micro-perforations are walled off by the tissue response to inflammation, forming small abscesses that can drain back into the lumen of the colon. However, sometimes more serious pathology can occur, according to the degree of perforation. A commonly-used grading system has been developed by Hinchey¹ :

I. confined pericolonic abscess
II. distant abscess (retroperitoneal or pelvic)
III. generalized peritonitis caused by rupture of an abscess, but not communicating with the colon lumen
IV. fecal peritonitis caused by free perforation of a diverticulum.

The sigmoid colon is usually involved, with a clinical presentation that has been called "left-sided appendicitis". If the ascending colon is the source of the trouble, it may be difficult to distinguish the inflammation from a true appendicitis.

Diagnosis: The pain of diverticulitis differs from that of symptomatic diverticular disease; it is usually acute in onset, persistent, and associated with signs of peritoneal irritation -- guarding and mild rebound tenderness. There may be nausea, vomiting, anorexia, and fever. Constipation or diarrhea can predominate. Bowel sounds may be normal, hyperactive, or absent. About 25% of patients with diverticulitis have a positive result for fecal occult blood, so that carcinoma of the colon is another differential diagnosis. In elderly women, ovarian cyst or tumor can cause confusion.

An erect chest and abdomen x-ray will detect a pneumo-peritoneum, which can occur in up to 12% of elderly patients. There may be small or large bowel dilatation, ileus, or radiographic signs of obstruction. However, computed tomography (CT) scanning, with oral and intravenous contrast, is the diagnostic tool of choice; it is clearly superior to barium enema. The latter can carry the risk of barium peritonitis. Ultrasound, being cheaper, convenient, and non-invasive, has been proposed as an alternative to CT; its chief benefit is in excluding gynecological pathology in elderly women.

Management: Very elderly patients with diverticulitis, or those who are immuno-compromised, should be hospitalized.

In uncomplicated diverticulitis, oral broad-spectrum antibiotics and oral hydration are likely to be successful within 2-3 days. Limiting oral intake to clear fluids ensures bowel rest. A CT scan will exclude complications.

In complicated diverticulitis, i.v. antibiotics and rehydration will be necessary, probably accompanied by surgery; laparoscopic resection is the preferred treatment for elderly patients.

Complications: The commonest complications of diverticulitis are: abscess formation, fistula, intestinal obstruction, frank perforation, and diverticular hemorrhage. It's beyond the scope of this summary to go into these in detail, but the original paper does so, to an adequate degree.

Recurrences: The risk of recurrence after an attack of acute diverticulitis that has not been surgically treated ranges from 25% to 33%. Recurrences do not respond well to medical treatment, and carry a high mortality. Elective resection is indicated after two attacks of uncomplicated diverticulitis.

Comment

Diverticular disease, a disorder of civilization, is something that affects people more as they get older. We hope that many people can avoid it in future, by adapting a suitable diet relatively early in their lifetime. If necessary, modern diagnostic approaches can help determine the correct diagnosis, and treatments are available to help patients through the two main conditions -- symptomatic diverticular disease and diverticulitis.
 

Source

• Diverticular disease in the elderly. RJ. Farrell, JJ. Farrell, MM. Morrin, Gastroent Clin North Am , 2001, vol. 30, pp. 475--496

Footnotes
1. Treatment of perforated diverticular disease of the colon. EJ. Hinchey, PH. Schaal, MB. Richards, Adv Surg, 1978, vol. 12, pp. 85--109

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