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Diverticulosis and Diverticulitis

Date issued:  February 2022 

For review:  February 2024 

Ref: A-285/AC/Colorectal/Diverticulosis and Diverticulitis v3 

PDF:  Diverticulosis and Diverticulitis final February 2022 v3 [pdf] 213KB

Diverticulosis and Diverticulitis

Diverticulosis occurs when small defects in the muscle of the wall of the large intestine (colon) allow small pockets or pouches (diverticula) to form. Diverticulitis is infection or inflammation of these abnormal pouches. Together, these conditions are called
diverticular disease.

Diverticular disease is not associated with more serious conditions, such as bowel cancer, despite some similar symptoms.

Causes of diverticulosis:

Diverticulosis is extremely common. Getting older and diet may be the most common risk factors. More than half of all adults over the age of 70 have the condition and most are unaware that they have diverticulosis. It is less common in people under the age of
50. One possible contributing factor is a low fibre diet and there may be genetic causes.


Diverticulosis is usually asymptomatic (has no symptoms). When many diverticula (pouches) are present, the normal smooth working of the bowel can be affected. This may cause a range of symptoms including:

• Abdominal pain and bloating
• Constipation and diarrhoea
• Flatulence
• Blood in the faeces, this is usually minor, but if a diverticulum gets inflamed or is near a blood vessel, bleeding can sometimes be heavy
• Anaemia from repeated bleeding may occur.

Many of these symptoms are similar to those of bowel cancer. 
However diverticulosis is much more common, so these symptoms may be more likely to be due to diverticulosis than cancer. However, a specialist will usually assess these
symptoms. Diverticulitis seems to occur when inflammation develops in the diverticular wall. This causes a small infection to develop, which could form an abscess.

Symptoms include:
• Sharp pain, often located at a specific point, like in the lower left half of the abdomen
• Fever
• Distension (bloating) of the abdomen
• Nausea and vomiting

Diagnosis methods:

Since diverticulosis is often asymptomatic, it tends to be discovered during examinations for other conditions, such as suspected colorectal cancer. However, diverticulitis is usually diagnosed during an acute attack.

Tests to confirm the diagnosis of diverticular disease may include:
Medical history: including dietary habits
Physical examination: including rectal examination
Colonoscopy: a slender flexible tube is inserted into the anus, to allow the doctor to look at the entire length of the large intestine.
Virtual colonoscopy: (CT colonoscopy) a small tube is used to gently inflate the colon and a CT scan is then taken of the abdomen, outlining the colon.
CT scan: to detect abscesses outside the bowel lining.
Blood tests: to check for signs of infection.
Stool tests: to check for the presence of blood in the faeces or infection, which may mimic the symptoms of diverticulosis and diverticulitis.

Treatment Options for diverticulosis:

For people with diverticulosis, there is no proven way to prevent the formation of new diverticula. Treatment revolves around the settling symptoms, and may include:

• A gradual switch to diet with increased soluble fibre which usually leads to an improvement in bowel habit. Examplesinclude broccoli, oat bran, whole meal or whole    grain bread,whole grain cereals, brown or wild rice, whole wheat pasta and fibre supplements, such as ispaghula husk (Fybogel)
• Short term use of laxatives to treat and prevent constipation.
• Surgery, very rarely required, but elective surgery may be indicated to remove seriously affected bowel segments whensymptoms are disabling.

Treatment options for diverticulitis:

Diverticulitis occasionally requires admission to hospital. Mild symptoms can be treated at home with a low fibre diet during a flare up and returning to a higher fibre diet when the inflammation has settled. Otherwise, if you have been assessed, further treatment may include:
• No eating or drinking, intravenous fluids are given to rest the bowel.
• Antibiotics.
• Pain-killing medications.
• Surgery is rarely required. If the weakened sections of bowel wall have ruptured or become obstructed, or if the attack of infection fails to settle.

Suggestion for Self-Care:

• Increasing the amount of fibre in your diet over a period of several weeks. This will prevent side effects associated with a high fibre diet, such as bloating and wind. Remember that some people find a diet high in fibre can make their symptoms worse.
• Drink plenty of fluids, at least 8 glasses (2-3 litres) of water a day.
• Avoid excessive amounts of sugar, sweets or fatty foods.
• Increase your daily intake of green vegetables.
• Consider using a fibre supplement (such as Fybogel).
• Exercise regularly to encourage bowel function and peristalsis (wave like contractions, which moves the poo through the bowel).

Where to get help:

Your doctor, specialist nurse, dietitian

Tips for increasing fibre, don’t underestimate the relevance of what you eat and drink and how it impacts on your bowels.

• Swap white bread for whole meal or whole grain bread.
• Swap refined cereals such as Rice Krispies® or Cornflakes® to wholegrain versions, such as porridge/BranFlakes®/Weetabix®/Shredded Wheat®.
• Add unprocessed bran to the diet, either in a dry state or mixed with other foods.
• Swap white rice and pasta to brown/whole wheat varieties
• Add extra vegetables to mince, casseroles, soups, stews, curry or chilli.
• Add beans and pulses to mince, casseroles, soups, stews, curry or chilli.
• 5 portions of fresh fruit and vegetables
• Try new fruit and vegetables that you’ve not had before.
• Snack on a piece of fruit or vegetable sticks.
• You can use fresh, frozen or tinned fruit and vegetables.
• Sprinkle seeds (e.g., pumpkin seeds, golden linseeds, sunflower seeds) over soups, salads or yoghurts.
• Choose foods labelled with 'high-fibre'.
• Keep the skins on fruit and vegetables when possible. Some skins of some fruits are often rich in fibre e.g., pears, tomatoes and potatoes.

Things to remember:

• Diverticulosis is the formation of abnormal pouches in the bowel wall.
• Diverticulitis is inflammation or infection of these abnormal pouches.
• Together, these conditions are known as diverticular disease.
• A diet low in fibre is a known risk factor for diverticular disease.

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