Pathophysiology
Elevated intraluminal pressure from low-fibre diet forces mucosa through vasa recta gaps. Faecal stasis and micro-perforation in a diverticulum trigger localised inflammation, abscess, or free perforation.
Sources: AGA Clinical Practice Update on Diverticulitis (Gastroenterology 2021;160:906); ASCRS Clinical Practice Guidelines for Diverticulitis (Dis Colon Rectum 2020;63:728)
Clinical presentation
Diverticulosis is often asymptomatic; may cause painless lower GI bleeding. Acute diverticulitis: left lower quadrant pain, low-grade fever, altered bowel habit, tender palpable mass. Complications: abscess, fistula (colovesical), stricture, perforation with peritonitis.
Sources: AGA Clinical Practice Update on Diverticulitis (Gastroenterology 2021;160:906); ASCRS Clinical Practice Guidelines for Diverticulitis (Dis Colon Rectum 2020;63:728)
Diagnosis
Contrast-enhanced CT abdomen/pelvis is first-line - pericolonic fat stranding, wall thickening, abscess. Colonoscopy after resolution to exclude neoplasm mimicking mass, generally 6-8 weeks later. Avoid colonoscopy in the acute phase (perforation risk).
Sources: AGA Clinical Practice Update on Diverticulitis (Gastroenterology 2021;160:906); ASCRS Clinical Practice Guidelines for Diverticulitis (Dis Colon Rectum 2020;63:728)
Management
Uncomplicated: outpatient management with fluids and observation; antibiotics selectively rather than routinely (per AGA guidance). Complicated (abscess, perforation, obstruction): IV antibiotics, percutaneous drainage of abscesses >3-4 cm, surgery for Hinchey III/IV or refractory disease. High-fibre diet reduces recurrence.
Sources: AGA Clinical Practice Update on Diverticulitis (Gastroenterology 2021;160:906); ASCRS Clinical Practice Guidelines for Diverticulitis (Dis Colon Rectum 2020;63:728)
