Diverticular disease
- A diverticulum is a blind pouch leading off the alimentary tract, lined by mucosa that communicates with the lumen of the gut
- Congenitial diverticulum of which Meckel is the most common involve all three layers of the gut wall
- Acquired diverticulum either lack or have an attenuated muscularis propria
- Can affect the oesophagus, stomach, duodenum but the most common site is the left side of the colon with the majority in the sigmoid colon
- Diverticular disease tend to refer to acquired outpouchings of the colonic mucosa and submucosa
- Rare in people under 30 but in the West, 50% of the population over the age of 60 has them
- Generally occur multiply and are referred to as diverticulosis
Morphology
- Multiple flask like outpouchings, 0.5 to 1 cm in diameter that typically occur in the distal colon
- The occur at the taeniae coli (where the vasculature penetrates the inner circular layer of the muscularis propria) and dissect into the subjacent appendices epiploicase
- The thin diverticulum wall is lined by mucosa and submucosa without significant muscularis propria although the muscularis between the diverticuli is hypertrophic
- One complication is diverticulitis – inflammation of the diverticulum after obstruction or perforation
Pathogenesis
- There are two factors important in the genesis of diverticula;
- Focal weakness in the colonic wall – at sites of penetrating blood vessels
- Increased intraluminal pressure – due to exaggerated peristaltic contractions
Clinical
- Usually asymptomatic but can be associated (in around 20%) with cramping, abdominal discomfort and constipation
- Diverticulitis can result in pericolic abscesses, sinus tracts and peritonitis