Diverticulitis

• Diverticula – herniations of colonic mucosa through circular muscles at the point where blood vessels penetrate (points of least resistance)
  • True diverticula – involve all layers of the colon (mucosa, muscularis propria and serosa)
    • E.g. Meckel’s diverticulum
  • False diverticula – don’t contain all layers; typically only contains the mucosa which is pushes through a defect in the muscular layer
• Diverticulitis – inflammation and infection associated with a diverticulum

Epidemiology/Etiology

• Most common in females and elderly
• 15% of diverticular diseases lead to diverticulitis
• Sigmoid colon is most common site of diverticula formation as it has the highest intraluminal pressure
• Diet – low fibre increases transit time of food, reduces bulkiness of stool
  • Increases intraluminal pressure and muscle hypertrophy
• NSAID intake – inhibits prostaglandin synthesis
• Smoking and alcohol

Pathophysiology

Diverticulosis – initial primary stage

• Hypertrophy and muscular incoordination leads to increased intraluminal pressure
• Clinical features
  • Can be asymptomatic
  • Fullness of abdomen, bloating, flatulence, vague discomfort

Diverticulitis – second stage

• Due to inflammation of one or more diverticula with pericolitis
• Clinical features
  • Persistent pain in left iliac fossa – radiates to back and groin
  • Abdominal tenderness, rigidity
  • Fever
  • Change in bowel movements – loose stool or recurrent constipation
  • Palpable and thickened sigmoid colon

Types of diverticulitis

Uncomplicated

• Pain and spasm over left iliac fossa
• Responds to antibiotics

Complicated

• Fever, ↑WCC, ↑CRP, tender colon
• Perforation
  • Ileus, peritonitis – can present with or without shock
  • Hartmann’s procedure may be performed
• Haemorrhage
  • Sudden and painless
  • Big rectal bleed

Classification – Hinchey’s classification

• Class I – diverticulitis with pericolic or mesenteric abscess
• Class II – diverticulitis with walled off pelvic abscess
• Class III – diverticulitis with generalised purulent peritonitis
• Class IV – diverticulitis with generalised faecal peritonitis

Investigatons

• Barium enema –  saw-tooth appearance (contraindicated in acute diverticulitis)
• Sigmoidoscopy – contraindicated in acute diverticulitis
• Ultra sound
• CT – shows thickening of muscle layer, abscess, perforation, fistula, involvement of organs like urinary bladder

Treatment

• Acute stage – conservative treatment i.e. bowel rest, antispasmodics, antibiotics
• Medical
  • High fibre diet
  • Antibiotics
• Guided aspiration of abscess and antibiotics
• Surgery
  • Resection of sigmoid colon and colorectal anastomosis – for majority of cases
  • Hartmann’s procedure – only for cases of acute diverticulitis complicated with sepsis/perforation/peritonitis
    • Combination of sigmoidecomy, end colostomy and closure of anal stump