• Diverticular
• Symptoms
• Treatment

Diverticular disease


Viewed from the outside

What is diverticular disease?

• This is a condition where there are “pockets” on the colon.
  • These are “ballooned out” areas that form in weak spots on the colon presumably in response to high pressure in the bowel.
  • Diverticular disease is common - and becomes more common with age.
    • More than 1/3 of people over 45 years and,
    • 2/3 people over 85 years have diverticular disease.


• The cause of diverticular disease is unknown.
  • It is a disease that is much more common in Western populations.
  • It is uncommon in Asian and African populations.
  • This has given rise to the idea that the low dietary fibre in the Western diet is the cause of diverticular disease.
    • This is only a hypothesis.
    • There is only limited evidence linking low fibre intake with diverticular disease.
    • There is no evidence that an increase in dietary fibre can prevent or delay progression of the condition.
  • There is likely to be a dietary influence but this could equally be some other dietary factor - perhaps a rice-based diet is less likely to give problems that our strongly wheat-based diet.

Symptoms and complications

• Diverticular disease can be present without any symptoms.
  • It may be found because of a colonoscopy performed for other reasons.
  • If this situation no treatment or change in diet is required.


• The most common symptom is lower abdominal cramping pain.
  • Particularly in the left lower abdomen.
  • This may be prior to or just after passing a bowel motion but can be at any time.
  • There is some overlap with symptoms from irritable bowel syndrome.
  • The cause of pain with diverticular disease is not well understood.
    • It is partly because of enlargement of the muscle layers of the colon leading to more "spasm".
    • Equally important may be distension from trapped wind.
    • Overgrowth of bacteria may occur - with or without overt evidence of "diverticulitis" (see below).
    • Inflammation of the affected bowel can occur in the absence of infection. (The cause of this associated inflammation is unknown.)


• The bowel motions can alter in form and consistency.
  • Sometimes there is constipation with thin pencil-like motions.
  • Sometimes there is urgency and semi-formed motions.

Complications of diverticular disease

• The most common complication is rectal bleeding.
  • This is bleeding of sudden onset that lasts for 12 – 48 hours then settles without treatment.
  • Occasionally the bleeding can be brisk enough to cause faintness and there is enough loss of blood to require hospital admission and blood transfusion.
  • The risk of a further bleed is about 1/3 over the next 3-5 years.
  • Rectal bleeding is more commonly due to piles or an anal fissure even if there is known diverticular disease.


• Diverticulitis - infection within the "pockets".
  • Infection within one of the pockets can cause more severe and prolonged pain that may last for several days (up to a week).
  • There may be marked tenderness in the left lower abdomen and sometimes fevers, sweats, nausea, loss of appetite.
  • A blood test may show some inflammation.
  • These infections can be recurrent.
  • Treatment by antibiotics (see below).


• Rarely the infection can create abnormal connections with other surrounding structures (fistula).
  • One example is a connection between the colon and the bladder.
  • This will give recurrence bladder infections and air in the urine.

Can the disease be prevented or can worsening of the disease be prevented?

• The usual advice is to increase dietary fibre intake.
  • The evidence for this approach is lacking but should at least be tried for a period. Some people with narrowing of the colon as a consequence of the diverticular disease may actually have more abdominal pain with increased dietary fibre.
  • Increased fibre is better taken as insoluble fibre and not cereal fibre. The easiest way to do this is to take a fibre supplement such as Normacol.
  • Normacol is available at your chemist.
  • Cereal fibre (bran) may aggravate the symptoms by increasing wind formation.


• The advice to avoid nuts and seeds has no basis and is best ignored.
  • The pockets in diverticular disease are "wide mouthed" and it is unlikely that food contents lodge and cause episodes of infection.
  • In fact, there is no recorded case of blockage of a diverticulum by nut or seeds.
  • This commonly given advice is based on theory only (a dubious theory).


• A diet that reduces wind production may be sensible (see exclusion diet).
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What treatments are required?

• The pain in the lower abdomen may be relieved by anti-spasmodics.
  • The best medication is probably Colofac (unfortunately no longer funded).
  • Alternatives are Buscupan or Merbentyl (not available now).
  • Side-effects such as “dizziness, drowsiness or feeling spaced out” limit the usefulness of this medication for some people.
  • Currently Buscupan 10mg as required is all that is available and I do not think this is that helpful for most people.


• Antibiotics.
  • This will be most helpful if there are clear signs of diverticulitis (as above).
  • The usual approach is to use Amoxil and Flagyl (metronidazole) or Tiberal for 1 week.
    • Shorter courses can be effective in some people.
  • Rarely if the infection does not settle with tablets then admission to hospital is required for intravenous antibiotics.
  • Some people with milder symptoms do get an improvement with antibiotics. Perhaps 3-4 days of metronidazole (Flagyl) on an intermittent basis is reasonable.


• The most accurate test for diagnosis of infection is an abdominal CT scan – but this is only needed for more severe infections.


• At some stage a colonoscopy is required but it is better to wait for 1-2 months to make sure the infection has settled.
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What about surgery?