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Diverticular disease

What is diverticular disease?

A diverticulum is an outpouching or pocket on the wall of the bowel. These pockets commonly occur in areas of weakness in the bowel wall where the blood vessels pass through. Diverticular disease is merely the presence of these pockets in the bowel (also known as diverticulosis). It is a common condition affecting around 70% of people by the age of 70 years. A person with diverticular disease may develop diverticulitis, diverticular bleeding or perforation.

What is diverticulitis?

Diverticulitis is inflammation of the diverticula. It is caused by irritation of the diverticula, and might be induced by solid stool getting trapped within one of the pockets causing irritation.

What are the symptoms of diverticulitis?

Diverticulitis causes abdominal pain which is usually located in the left lower aspect of the abdomen, as it is this part of the bowel (sigmoid colon) which is most commonly affected. If another part of the bowel develops diverticulitis (e.g. the caecum, more common in people of Asian ethnicity), the pain may be elsewhere. Other associated symptoms can include fever, vomiting, nausea, constipation and urinary difficulties (pain with urination, burning, frequency).

What causes diverticular disease?

The most accepted cause is increased pressure within the lumen of the bowel, which can occur with constipation and lack of fibre. These pockets develop over time due to the high pressures within the bowel. Some patients are more prone to this condition than others, for example people with connective tissue disorders. However despite diverticular disease being extremely common, most patients do not develop symptoms.

As with most diseases, prevention is better than cure. A diet high in fibre with additional fibre supplements such as Metamucil or Benefiber can be beneficial. Avoiding constipation, straining and dehydration may prevent the formation of diverticular disease and minimise the chance of diverticulitis (inflammation).

Should I avoid eating foods containing seeds, nuts, grains?

There is no scientific evidence that consuming any of these increases the risk of diverticulitis. In the past we advised people to avoid such foods as we thought they could become lodged in the diverticulum and cause diverticulitis. However this has not been proven scientifically. One can try avoiding these however there is no evidence to suggest it will reduce the chance of diverticulitis.

What are the complications of diverticulitis?

There is a wide range of symptoms and complications depending of the severity of the disease. The diverticulitis can be mild and resolve by itself. It may require oral antibiotics or for more severe cases intravenous antibiotics and hospital admission. More severe attacks can cause bowel perforation and may need radiological drain placement or major surgery.

Diverticular bleeding can occur if one of the small blood vessels around a diverticulum gets traumatised and ruptures. This results in painless rectal bleeding. Usually this is rapid onset, bright red and can be very heavy. If the bleeding is arising higher up in the colon the bleeding can be dark red or maroon. On most occasions the bleeding stops without any intervention.

What investigations are required to confirm diverticulitis?

A CT scan of the abdomen will confirm the presence of diverticulitis in a patient with symptoms suggestive of this. A blood test may be performed as a marker of the body's response to severity of inflammation.

Once an attack of diverticulitis has settled, your surgeon may recommend a colonoscopy be performed to view the inside of the colon. This is typically performed no earlier than six weeks after an attack. The colonoscopy is not performed to look for diverticular disease, rather to exclude any sinister pathology such as bowel cancer, which can at times present with similar symptoms and signs. This is especially important if there are any other concerning symptoms such as rectal bleeding, weight loss, family history of bowel cancer, or any unusual features on CT scan. In one study of patients undergoing colonoscopy following diverticulitis, 26% had undiagnosed polyps found.

What is the chance of another attack of diverticulitis?

The chance of a second attack of diverticulitis is around 20-40%. It is difficult to predict who is likely to suffer recurrent diverticulitis. It is for this reason that surgical resection of the bowel is only rarely performed after one or two attacks, as many patients will avoid future troubles without surgery.

If I require surgery, will a need a bag (colostomy)?

It depends.... If you need an emergency operation due to perforation from diverticulitis, you have a high chance of needing a temporary colostomy. The chance of this depends on how sick you are at the time of surgery, the degree of contamination within the abdomen, and your overall health. Colorectal surgeons are more likely to perform a bowel resection without a stoma, when compared to general surgeons. In appropriately selected patients this is a safe alternative with an incidence of anastomotic leak (i.e. leak from the bowel join) around the same as for elective surgery.