Diverticulosis

Basics

Single (diverticulum) or multiple (diverticula) colonic wall outpouchings from colonic muscle dysfunction, usually acquired
Sequence:
- Insufficient amounts of dietary fiber cause diminished stool bulk
- Increased colonic contractions to propel stool through colon cause increase in intraluminal pressure
- Increased pressure forces mucosa and submucosa to herniate through muscularis propria at its weakest point, where vasa recta penetrate

Occurs anywhere in GI tract, although generally a colonic disease:
- Left sided: 95% (Western countries)
- Right sided: 70% (Asian countries)
- Sigmoid colon most common site
Pseudodiverticula:
- Outpouchings of mucosa and submucosa only
- Most common form of colonic diverticula
- True congenital diverticula (uncommon) contain all bowel wall layers
Common in Western society, owing to refined diet, and decreased fiber intake
Prevalence is age-dependent:
- 50% by age 60, 70% by age 80
- Affects men and women equally
Complications:
- 70% are asymptomatic
- <5% develop diverticulitis
- 5–15% develop bleeding; obesity is a risk factor:
  - Bleeding stops spontaneously in 75% of cases
- Inflammation (diverticulitis)
- Massive arterial bleeding usually from right colon:
  - Fecalith (dry, hard stool) erodes through arterial branch
- Perforation
- Abscess
- Obstruction

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