Diverticular Disease

What is diverticular disease?

Diverticular disease refers to a group of conditions related to the formation of small pouches in the wall of the colon, called diverticula. These pouches form at points of weakness in the muscular layer of the bowel, often where blood vessels pass through the wall.

Diverticular disease includes:

  • Diverticulosis: The presence of diverticula in the colon. Most people with diverticulosis have no symptoms and will remain symptom-free for life. In some cases — particularly with extensive diverticulosis — the normal function of the bowel may be affected, causing symptoms such as abdominal pain, bloating, constipation and diarrhoea

  • Diverticulitis: Inflammation of a diverticulum, typically due to increased pressure or a hard particle of stool becoming lodged in the pouch. The degree of inflammation can vary. Symptoms of diverticulitis including constant lower abdominal pain (usually left-sided), tenderness in the abdomen, fever or chills, nausea and vomiting

    Diverticulitis is divided into two forms:

    • Simple diverticulitis: ~75% of cases. No complications; usually responds to medical treatment without surgery.

    • Complicated diverticulitis: ~25% of cases. Complications include; abscess (collection of pus), fistula (tract between bowel and another organ), bowel obstruction (blockage), perforation (hole in the bowel) and peritonitis (serious infection of the abdomen). Surgery is often required in complicated cases.

  • Diverticular bleeding: Occurs when a small artery within a diverticulum erodes and bleeds into the bowel. This causes painless rectal bleeding, typically bright red or maroon in colour

What are the risk factors for diverticular disease?

  • Age >50 years

  • Male sex

  • Obesity

  • Smoking

How is diverticular disease diagnosed?

Diverticulosis is often discovered incidentally during investigations for other conditions, as it usually causes no symptoms.

Common diagnostic tests include:

How is diverticular disease treated?

Diverticulosis (without symptoms):

  • No specific treatment required

  • A high-fibre diet is recommended to maintain bowel health and is part of a healthy diet in general

    • Fibre-rich foods include fruit, vegetables, legumes, wholegrains, nuts, and seeds

  • Avoidance of nuts and seeds is no longer recommended — this is a myth unsupported by evidence

  • Occasional use of laxatives may be advised to relieve constipation

  • Rarely, surgery may be considered if symptoms are severe and not controlled with medical therapy

Diverticulitis:

Treatment depends on severity:

  • Mild cases may be managed at home with dietary changes, oral pain relief, and sometimes oral antibiotics

  • More severe cases often require hospitalisation for intravenous antibiotics and fluids, restriction of oral itake and close monitoring

  • Complicated or recurrent cases typically require surgical removal of the affected bowel segment

After recovery, a colonoscopy is usually recommended (if not done recently) to assess for underlying pathology such as polyps or cancer.

Diverticular bleeding:

Most episodes resolve without treatment. Further intervention may include:

  • Colonoscopy to identify and potentially treat the bleeding site

  • Angiography (used to locate and seal the bleeding artery)

  • Surgery, if bleeding is severe or persistent

Even if bleeding stops on its own, a follow-up colonoscopy is recommended to rule out other causes

What is the prognosis?

  • Diverticulosis:

    • 15–25% will develop diverticulitis

    • 5–15% will experience diverticular bleeding

  • Diverticulitis:

    • 85% of people with uncomplicated diverticulitis improve with medical treatment

    • 15% may require surgery

    • After treatment:

      • ~1/3 will remain symptom-free

      • ~1/3 will have intermittent abdominal symptoms without further diverticulitis

      • ~1/3 will experience a recurrent episode