Diverticula

Section: Colorectal Sub-section: Acute colorectal Curriculum: Curriculum, page 21

Definition

• common anatomical disorder characterised by acquired, sac-like mucosal projections (diverticula) through muscle wall.
• False diverticula because do not involve all colonic layers

Terminology

• Diverticulosis – the presence of colonic diverticula.
• Diverticular disease – clinically significant and symptomatic diverticulosis and may be caused by:
  • Diverticulitis or
  • Other less well-described manifestations (e.g., visceral hypersensitivity without evidence of inflammation).
• Symptomatic uncomplicated diverticular disease (SUDD) – persistent abdominal symptoms attributed to diverticula without diverticulitis or bleeding.
• Diverticulitis – acute or chronic symptoms in the presence of inflamed diverticula.
  • Uncomplicated – Computed tomography (CT) shows only colonic wall thickening with fat stranding.
  • Complicated – CT shows abscess, peritonitis, obstruction, fistula or haemorrhage.
• Diverticular bleeding – haemorrhage from diverticula (right- or left-sided)
• Segmental colitis associated with diverticulosis (SCAD) – inflammation resembling inflammatory bowel disease isolated to areas marked by diverticulosis.

Epidemiology

• More common in Western countries – associated with environmental/lifestyle changes.
• More right sided in Asian population
• Males more likely to develop at younger age; more females in older population
• Young patients more likely to suffer from recurrent diverticulitis
• Low fibre diet has epidemiological association with development of diverticular disease, however recommending fibre as treatment is based on poor evidence.

Aetiology

• Obesity
• Smoking
• NSAIDs
• ?low fibre diet

Pathogenesis

• There is uncertainty about the aetiology
• Thought to arise at weak points where perforating blood vessels penetrate the bowel wall.
• Traditional theory
  • Colonic pressure and colonic transit theory – patients with diverticular disease have prolonged transit times, and therefore increased segmental pressures. The sigmoid colon is the narrowest part with the highest pressures thus this is where you get diverticular disease. Thought to correlate with low fibre intake because this increases colonic transit times.
  • Neuromuscular dysfunction – causes increased pressures causing outpouchings.
  • Connective tissue – increased type 3:type 1 collagen ratios causes weakness in the bowel wall

Classification

	Hinchey classification
Stage I	Pericolic abscess confined by the mesocolon
Stage II	Pelvic abscess, distant from area of inflammation
Stage III	Generalised peritonitis resulting from pericolic/pelvic abscess rupture into peritoneal cavity
Stage IV	Faecal peritonitis resulting from free perforation of colonic diverticulum

Investigations

• CT is gold standard
• Colonoscopy – indicated for complicated disease, atypical imaging features or persistent symptoms

Management

• Lifestyle optimisation
• Medical therapy
  • Possible benefit to 5-ASA or probiotics short term.
  • Antibiotics – reasonable for no antibiotics in non-septic patients with uncomplicated disease - 3x RCT including STAND trail from Auckland
• Diverticular abscess – perc drain if size > 5 cm however no evidence basis

Emergency surgery:

• Hartmann’s
  • Complications:
    • Persistent sepsis in rectal/sigmoid stump
    • Stoma problems – necrosis, retraction, stenosis
    • Wound complications – dehiscence, infection
    • Permanent stoma
• Laparoscopic lavage:
  • trials:
    • LADIES The Netherlands:
      • Multicentre two-armed.
        • LOLA arm – laparoscopic lavage (n=46), Hartmann’s or resection and anastomosis (n=40 total) 2:1:1
        • DIVA arm – for faeculent peritonitis Hartmanns or resection and anastomosis 1:1.
      • LOLA arm closed early due to higher re-intervention rate, although there were fewer stomas and lower mortality (9% vs 14%).
    • SCANDIV
      • Laparoscopic lavage (n=101) vs colon resection +/- primary anastomosis (n=98). Reintervention rate higher in lap lavage, overall morbidity and mortality similar 13.9% vs 11.5%.
    • DILALA:
      • Randomised patients (n=65) to lap lavage or open resection. Lavage was shorted with faster recovery and lower mortality (7.7% vs 11.4%).
    • Meta-analysis of these three: Decreased stoma rate however it does not decrease mortality rate and increases short-term morbidity rate due to higher complication and reintervention rates
  • Contraindications:
    • Shock
    • Requirements for inotropes
    • Frailty
    • Immunosuppressants
    • Faecal peritonitis or visible colon wall breach seen at laparoscopy
  • Should do gas leak test during laparoscopy to exclude a hole before considering lavage alone.
• Resection with primary anastomosis
  • Leak rate 6%
  • Favourable in terms of wound and stoma complications

Elective resection

• Indications:
  • Fistula
  • Obstruction from stricture
  • Persistent diverticulitis unresponsive to medical therapy
  • Recurrent episodes > 4, esp. young patients