Diverticular Disease (DD)

Originally published on: April 6th, 2017. Last modified on October 15th, 2021

What is Diverticular Disease?

Diverticular Disease – also known as DD –  is the name given to small pouches (sacs) known as diverticula, that protrude outwards from the wall of the large intestine. Each diverticulum consists of a small part of the inner lining of the intestine that has been forced through the muscular layer of the intestine forming a small hernia. The number of protrusions will differ from person to person. The protrusions are generally the size of small grapes.

Diverticula can appear in any part of the colon. Among people in Westernised countries, diverticula are most commonly found in the sigmoid part of the colon. Diverticular Disease is common predominantly among middle-aged to older people.

There are some other terms that are used to refer to this condition:

  • Diverticulosis – the condition in which small sacs appear but cause no symptoms
  • Diverticular Disease – used to describe all forms of the presence of diverticula, also known as DD
  • Symptomatic diverticulosis – the condition in which some symptoms are present but there is no infection in the sacs
  • Diverticulitis – the inflammation of the sacs usually caused by an infection (complication)

Diverticular Disease Symptoms

Many people with diverticula will not suffer from any symptoms and may have diverticula discovered during a routine medical examination. Some patient’s experience;

  • A change in bowel habit (either more constipated or more loose than usual)
  • Discomfort, especially on the left side of the abdomen
  • Pain, which arises because the diverticula become inflamed (diverticulitis)
  • Blood in the motions. If this occurs for the first time it is important to tell your doctor

What Causes Diverticular Disease?

It has not yet been confirmed what exactly causes diverticular disease but researchers and scientists do have a number of theories.

  1. Low fibre intake
  2. Race / Genetics
  3. Dietary factors other than fibre
  4. Leading an inactive lifestyle
  5. Associated with ageing

Of the various possible explanations for the cause of diverticula, the evidence is strongest for a low fibre diet. However, the jury is still out on whether bran and fibre can be effective in treatment for uncomplicated DD or even prevent complications.

Dietary fibre contained in vegetables and fruits help to keep food bulky as it travels along the digestive tract. A diet low in fibre is less bulky and the muscles of the large intestine struggle to move the intestinal content. The extra strain involved is the likely cause of thickening of the intestinal muscles. The large intestine with thickened muscles takes on a corrugated shape. When the muscles contract, the intestine forms compartments and the compartments increase, this in turn forces out a diverticulum. This is the most widely held view of how low levels of fibre in the diet lead to the formation of diverticula. 

Diagnosing Diverticular Disease

When you visit the doctor, you will be asked about your symptoms. It is important that you are honest with your doctor about your problems. The doctor may then ask to examine you which might start with an examination of your abdomen, looking for tenderness or any lumps. 

The doctor may also want to make a digital examination of your rectum. The doctor will insert a finger into the anus and will look for any irregular shape. You may also be required to have a blood test in an attempt to rule out other possible conditions such as IBS and Coeliac Disease. If further tests are required your GP will refer you to your local hospital. 

Tests for Diverticular Disease

Normally before further tests can be carried out a bowel cleansing will be required. Bowel cleansing will clear the colon of all faeces which will make it easier to assess the colon in tests. Most cleansing preparations will be taken a few days before a test is carried out and usually consist of a powder which you add to water and drink – causing diarrhoea which will empty the contents of your bowel. 

After the bowel is empty you may undergo one of the following tests;

Contrast Enema

A contrast enema consists of the use of x-rays and an enema. A lubricated tube is inserted into the anus through which the liquid contrast enema flows into the rectum and colon. The lubricated tube is removed. The contrast enema will contain barium sulphate which when captured in an x-ray will present a clear image of the shape of the large intestine. If there are diverticula present in the patient, they will appear within the x-ray image. 


An endoscope is an instrument that lets the doctor see the interior of the digestive tract. The instrument is a flexible tube with a light and camera at one end and an eyepiece at the other end. To investigate a possible case of DD, the tube is inserted into the anus to the large intestine. The endoscope can help a doctor identify any diverticula and also allows the doctor to take small samples from the bowel wall for further inspection and examination.

Computerised Tomography (CT scan)

A CT scan may be undertaken if diverticula appear extensive or if symptoms of a patient are severe because it is less invasive than an enema or endoscopy. The CT scan will produce a series of images of cross sections of tissue which can provide a more detailed 3D image of the colon.

Blood Tests

There are other tests that may also be carried out when diagnosing DD. These include blood tests; blood is taken to find evidence of infection which would suggest that the colon is infected.

Ultrasound Sonograph

Another test is an Ultrasound Sonograph. This procedure is carried out in some cases because it is non invasive and can help identify any possible abscesses.

MRI Scan

An MRI scan is not commonly used to examine the abdomen, but when used it can help identify diverticula and the presence of complications, such as abscesses or fistulae.

Further Information

Depending on the severity of diverticula identified and the severity of a patient’s symptoms, once DD is diagnosed, your condition can be monitored intermittently. It is important to provide an update of your condition to your doctor to ensure that the condition does not worsen and further complications do not arise.

For more information on diverticular disease such as diagnosis, tests and how it is treated, please open our Diverticular Advice Sheet. We also offer more detailed information on the site about Treatment, and Diverticulitis should this be more relevant for your situation.