DIVERTICULAR DISEASE (Robbins pp 823)

A diverticulum is a blind pouch coming from the alimentary tract. Congenital diverticula have all three visceral layers. Acquired diverticula only have mucosa + submucosa. Diverticulosis = presence of diverticula (no symptoms), diverticulitis: inflammation of diverticula. Diverticular disease is more common in the colon, with over 50% prevalence rate > 60yrs old.

Pathogenesis/Aetiology: Two main factors: 1) focal weakness in wall of bowel, 2) increased intraluminal pressure. Neurovascular structures penetrate muscularis propria, causing focal areas of weakness. Unusually strong peristaltic contractions produce increased intraluminal pressure.

Clinical features: Majority of times ≫ patient asymptomatic. When inflamed: you get intermittent left lower quadrant pain, with alternating constipation / diarrhea, PR bleeding (if necrosed), tenesmus.

Macroscopy / Microscopy: Small outpouchings (0.5-1cm) that extend into the mesentery of bowel. Sigmoid most often affected. Histologically: You see diverticula with colonic mucosa and submucosa. Muscularis propria is absent (if acquired). Muscularis propria of adjacent wall is hypertrophied.

Complications:

1) Inflammation ≫ fibrosis ≫ obstruction,

2) Perforation ≫ peritonitis,

3) Fistula,

4) ulcerative ≫ haemorrhage.

Category: Pathology Notes