Description

• Diverticular disease includes asymptomatic diverticulosis, symptomatic uncomplicated diverticulitis, symptomatic complicated diverticulitis, and diverticular bleeding.
• Diverticula: Saclike protrusion of the mucosal and submucosal wall of the colon:
  • Diverticulosis has a higher prevalence in societies that consume a low-fiber diet.
  • In Western societies, 90–95% of diverticulosis is left-sided; Asian populations have more right-sided disease.
  • Prevalence of diverticulosis and number of diverticula increase with age.
• Diverticular hemorrhage: Occurs in 3–5% of patients with diverticular disease:
  • Accounts for >40% of lower GI bleeds and 17–40% of cases of hematochezia in general
  • Bleeding more common if right-sided.
• Uncomplicated diverticulitis: Typical presentation, affects 10–25% of patients with diverticulosis
• Symptomatic uncomplicated diverticular disease [SUDD]: Recurrent abdominal pain attributed to diverticula in the absence of macros­­copically overt colitis or diverticulitis (1)
• Complicated diverticulitis includes associated abscess, perforation, fistula, or stricture.
• System(s) affected: Gastrointestinal

Epidemiology

• Diverticulosis <5% in general population, diverticulitis 1–2% in the US (1)
• Diverticulitis: 2,400–3,800/100,000
• Yearly mortality rate: 2.5/100,000

• 5% by age 40; 30% by age 60; 65% by age 85
• Male = Female overall, but more male <65 and more female >65

Risk Factors

• Age >40
• Low-fiber diet
• Sedentary lifestyle, obesity
• Previous diverticulitis and number of diverticula
• Smoking increases the risk of perforation (1).
• NSAIDs, steroids, and opiate analgesics increase diverticular hemorrhage whereas calcium channel blockers and statins have protective effects.

• No known genetic pattern
• Asian and African populations have lower prevalence, but diverticular disease develops with adoption of a Western lifestyle.

General Prevention

High-fiber diet (>30 g/d of fiber) or add nonabsorbable fiber (psyllium)

Pathophysiology

Diverticula form at the site of penetration of the mucosa by the vasa recta. Structural changes result in decreased resistance to intraluminal pressure. Diverticulitis occurs when perforation of the diverticulum occurs.

Etiology

• Age-related degeneration of mucosal wall; increased intraluminal pressure from dense, fiber-depleted stools and abnormal colonic motility.
• Occur at areas of weakness from junctures of penetrating arteries in the muscular wall
• Bleeding is caused by medial thinning of the vasa recta and weakening of the artery as it courses over the neck of the diverticula.
• Diverticulitis occurs when increased intraluminal pressure results in local inflammation and necrosis, leading to micro- or macroperforation.
• Chronic microscopic inflammation around diverticula is also a cause (1).
• Another hypothesis is shifting in intestinal microbiota, leading to chronic inflammation (1,2).
• Evidence for overlapping of diverticular disease and irritable bowel syndrome (IBS) (visceral hypersensitivity)

Commonly Associated Conditions

Connective tissue diseases, colon cancer, and inflammatory bowel disease