Diverticular Disease

Basics

Description

Diverticulum (single) or diverticula (multiple) are outpouchings of the colonic wall. Diverticular disease is a spectrum of diseases impacting the entire GI tract (except the rectum):

  • Asymptomatic diverticulosis: common incidental finding on routine colonoscopy or imaging
  • Symptomatic diverticulosis: also known as symptomatic uncomplicated diverticular disease (SUDD); recurrent abdominal pain attributed to diverticulosis without colitis or diverticulitis (1)
  • Acute diverticulitis: diverticular disease with associated inflammation and/or infection
    • Uncomplicated diverticulitis: abdominal pain and leukocytosis without peritoneal signs or systemic toxicity
    • Complicated diverticulitis: secondary abscess formation, bowel obstruction, perforation, peritonitis, fistula, or stricture in the setting of diverticular inflammation
  • Diverticular bleeding
    • Accounts for >40% of lower GI bleeds; often presents as painless hematochezia unless associated with active diverticulitis; bleeding is more common with right-sided diverticula.

Epidemiology

Incidence

  • Diverticular disease accounts for ~300,000 hospitalizations per year in the United States.
  • Diverticulitis occurs in 1–2% of the general population and in 4% of patients with diverticulosis (1). Diverticular bleeding occurs in 3–5% of patients with diverticulosis.

Prevalence

  • Prevalence of diverticulosis and the number of diverticula increase with age.
    • Diverticulosis occurs in 20% of those aged 40 years, 60% of those aged 60 years, and 70% by the age of 80 years.
    • Incidence of diverticulitis increased from 62 to 75/100,000 people from 1998 to 2005; largest increase in patients <45 years of age—mostly due to changes in diet
  • Male = female overall; more common in men <65 years of age and more common in women aged >65 years

Etiology and Pathophysiology

Diverticula form at points of weakness along the intestinal wall where small blood vessels (vasa recta) penetrate through the muscular layer of the colon.

  • Age-related degeneration of the mucosal wall; increased intraluminal pressure from dense, fiber-depleted stools; and abnormal colonic motility contribute to diverticulosis.
  • Most right-sided diverticula are true diverticula (involves all layers of the colonic wall).
  • Most left-sided diverticula are pseudodiverticula (outpouchings of the mucosa and submucosa only).
  • Diverticulitis occurs when local inflammation and infection contribute to tissue necrosis with risk for mucosal micro- or macroperforation.
  • Alterations in intestinal microbiota contribute to chronic inflammation (1).
  • Thinning of the vasa recta over the neck of the diverticula increases susceptibility to bleeding.
  • Diverticular disease and irritable bowel syndrome (IBS) may represent the same disease continuum.

Genetics

  • Though genetics may play a role, there is no known genetic pattern.
  • Asian and African populations have lower overall prevalence but develop diverticular disease with adoption of a Western lifestyle.

Risk Factors

  • Age >40 years; low-fiber diet
  • Sedentary lifestyle, obesity; previous diverticulitis; risk rises with the number of diverticula.
  • Smoking increases the risk of perforation (1).
  • Risk of diverticular bleeding increases with NSAIDs, steroids, and opiate analgesics. Calcium channel blockers and statins protect against diverticular bleeding.

General Prevention

  • High-fiber diet or nonabsorbable fiber (psyllium)
  • Regular physical activity

Commonly Associated Conditions

Colon cancer, connective tissue diseases, obesity, IBS, and inflammatory bowel disease

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