Condition: Diverticular Disease

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.

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.

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.

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.

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.