Condition: Diverticular Disease

Diverticulosis is a common condition of the colon that causes small pockets to form along its length.

What are
diverticulosis and diverticulitis?

Diverticulosis is a common condition of the colon that causes small pockets to form along its length. This is a western disease, and diverticulosis is very common; it affects 50% of people over the age of 60, and it leads to 2.7 million outpatient appointments and 300,000 hospital admissions in the USA each year.

Diverticulitis describes acute inflammation of a segment of colon with diverticula. It does not mean that there is infection, but that the bowel is inflamed; at surgery it looks thickened, stiff and oedematous.

What causes
diverticulosis / diverticulitis?

Diverticula were originally thought to be caused by the innermost lining of the bowel (called the mucosa) being forced out by pressure within the lumen of the bowel. However, it is now generally thought to be caused by chronic low grade inflammation in the gut.

It is becoming more common, and there has been a 21% rise since 2003. The prevalence in younger patients is also increasing.

Patients suffer from this condition because of a combination of lifestyle factors and their genetic predisposition. The most important modifiable risk factors are:

  1. A low fibre diet. The chance of getting diverticular disease reduces with every 5g/day fibre you take, but this reduction does depend on the type of fibre you eat.
  2. Red meat intake (particularly unprocessed red meat) is associated with an increased risk of diverticulitis. Substitution of poultry or fish for one serving of unprocessed red meat per day can reduce your risk.
  3. Vitamin D level. Diverticulosis is also associated with Vitamin D levels, and lower levels are associated with an increased risk of diverticulitis.

Smokers and those that have had gallstones are also at an increased risk.

What are the
symptoms of diverticulosis?

Most people with diverticulosis are asymptomatic and probably never know they have the condition. It is commonly found during routine colonoscopy or CT scans. Some people may have diverticulosis and be very symptomatic.

Symptoms may include bloating, constipation, abdominal pain and it presents much like Irritable Bowel Syndrome. This is known as Symptomatic Uncomplicated Diverticulosis (SUDD).

Patients with diverticulitis will often complain of pain in the left side of the abdomen, and develop a temperature and an altered bowel habit.

The severity of diverticulitis ranges, but it is often described in terms of being ‘uncomplicated’ or ‘complicated’. Uncomplicated means it can be treated with simple medicines and lifestyle advice, while complicated means that the diverticulitis has caused a structural change in the bowel (like a perforation, stricture or obstruction). Occasionally, a diverticulum can be obstructed by faeces and this can lead to perforation and the development of an abscess. This can make patients very unwell indeed and it may require treatment in a hospital and occasionally it needs surgery.

How is
diverticulosis diagnosed?

Diverticulosis is commonly diagnosed as an incidental finding on a CT scan or at colonoscopy. However, if you are symptomatic your doctor will choose one of these two tests to investigate the colon. This is made on an individual patient basis and based on an individual’s specific risk, the presentation of the condition and their risk profile for colonoscopy and the associated bowel preparation.

Treatment for diverticulosis

Treating uncomplicated asymptomatic diverticulosis

It is important that you recognize that this suggests your diet may not be doing your bowel any good and that you need to change some of your lifestyle factors to improve your health and prevent this becoming worse. This means you need to do the following:

  1. Aim to eat at least 30g of fibre per day.
  2. Ensure you make changes to your diet slowly, and increase the fibre by 5g each day over a week until you reach the recommended daily intake or you will be bloated.
  3. You need to do this for life! A healthy gut requires a fundamental change in many people’s dietary behaviour.
  4. Reduce the amount of red meat and processed meat you eat. Try replacing one meal a day with white meat (poultry or chicken).
  5. You can eat nuts and seeds! This is a common misconception.
  6. Stop smoking – if you do
  7. Exercise regularly.
  8. Ask your GP to check your Vitamin D levels.
  9. Avoid taking Ibuprofen or drugs known as NSAIDs unnecessarily.
  10. Try taking a bulk forming laxative like methylcellulose if you are constipated. Your GP can help prescribe it.
  11. Drink enough water – you need about 2 litres of fluid a day.
  12. Lose weight – if you do the above, this will happen anyway!

Have you noticed this is the same advice for reducing your risk of cancer or heart disease? This is no accident and it’s because the same biological processes that cause diverticulosis cause these diseases.

Treating symptomatic uncomplicated diverticulosis

This is more difficult and it requires a more personalised approach. All of the advice above is important, but sometimes other approaches are needed.

This is because some evidence suggests patients with SUDD have very sensitive guts to stretch which causes pain. They also have low levels of inflammation.

The trial data for the use of anti-inflammatory medicines like Mesalazine has been disappointing, and they are not typically recommended. Drug trials with specific antibiotics such as Rifaxamin have also not shown an effect.

Patients should see a gastroenterologist or surgeon with a specialist interest in this condition.

Treatment for diverticulitis

The main thing is to rule out a complication. So, if you suspect this you need to see a doctor, who will typically perform a blood test and perform a CT scan. A test called a CRP is particularly good at predicting the severity of the disease. This allows the doctor to rule out other diagnoses and target the treatment.

Treatment depends on the severity of the disease:

Mild disease

Evidence now suggests this can be managed safely at home. The most controversy at the moment concerns the use of antibiotics. Eight randomised control trials have now been performed and the consensus is that, in mild disease, antibiotics DO NOT make diverticulitis better. Many GPs prescribe antibiotics for this condition but it is likely not to help.

Take regular pain killers but avoid ibuprofen. Take a small dose of stool softener if you are constipated and plenty of fluids.

Rest the gut. This means a fluid or liquid diet only while you have severe pain and your gut is not working properly. Avoid a high protein diet, rich food, spicy food and alcohol.

Be patient – you are going to feel unwell for about 5 to 10 days, and you need to take time off work and rest.

The prognosis is good. In patients managed this way, less than 5% will need surgery. However, about 20% of patients with diverticulitis will have a recurrent episode within 5 years.

Moderate or severe disease

This requires specialist input and your GP needs to refer you urgently to a colorectal surgeon for management.

Treatment depends on the presence of infection, its severity and the presence of other possible complications from diverticulitis. This is usually determined from a CT scan.

In the presence of a localised abscess, it may be possible to treat this with antibiotics. However, sometimes it is necessary to perform a CT guided drainage. Surgery is only performed when patients are severely unwell, and there is significant contamination of the abdomen with pus or faeces. This requires an emergency operation and three procedures are commonly performed:

A laparotomy (a big cut on the tummy) removal of the diseased segment with the perforation and the formation of a colostomy (a bag). Many patients are worried about the presence of a bag, however this is a life saving treatment and it is usually reversible.

A laparoscopy (a key hole operation) with drainage of the infection and the insertion of drains. The benefit of this is that the patient avoids a colostomy, although this is put in about 14% of patients managed this way. When the patient is recovered, they can have an elective operation to remove this segment of disease and the bowel is rejoined with lower rates of colostomy formation. But, a recent study found that patients that underwent this procedure have three times the risk of developing peritonitis or requiring emergency surgery. The hospital stay can be long and the drains may need to remain in for several weeks.

Laparoscopic (key hole) removal of the diverticulitis segment with a primary anastomosis (join) with or without a temporary ileostomy. The benefit of this is that the stoma is more likely to be reversed as this is a much simpler operation. It also means that the patient is definitively treated at one operation. However, this is a high risk join to make, and this approach needs to be used in a highly selective way.

Sometimes, surgery is performed when the patient has recovered from their initial surgery or for the treatment of complications. This is a highly specialised type of surgery and should only be performed by a specialist colorectal surgeon.

Surgery is not without its risks. Elective surgery has a 10% anastomotic leak rate, and there is a risk of incontinence; 25% of patients complain of an altered bowel habit, abdominal distension or cramping. The rate of diverticulitis recurrence after resection (5-11%) is similar to the rate of recurrent hospitalised events (4-13%) if no surgery and the risk of recurrence is higher in young patients, smokers and in women.

The American Gastroenterology Association suggests against elective colonic resection in patients with an initial episode of acute uncomplicated diverticulitis. The decision for surgery is highly personalised and should be made on an individual basis.