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Diverticulosis And Diverticulitis

by Advanced GI WA

Many people have small pouches in their colons that bulge outwards through weak spots, like an inner tube that pokes through weak places in a tyre. Each pouch is called a diverticulum and when multiple pouches are present in the large bowel the condition is called diverticulosis. The condition becomes more common as people age and about half of all people over the age of 60 have diverticulosis. The condition is frequently found at colonoscopy and is not usually associated with any symptoms.

When the pouches become infected or inflamed, the condition is called diverticulitis. This will happen to approximately 10% of people with diverticulosis. Diverticulosis and diverticulitis are also called diverticular disease.

What are the symptoms?

Diverticulosis - most people with diverticulosis do not have any discomfort or symptoms. Occasionally symptoms may include mild cramps, bloating and constipation but other diseases such as irritable bowel syndrome (IBS) are a much more common cause of these symptoms.

Diverticulitis - the most common symptom of diverticulitis is abdominal pain which classically occurs in the left side of the lower abdomen but it may be in the centre of the lower abdomen and rarely on the right side of the lower abdomen. If infection is the cause then fever, nausea, vomiting, chills, cramping and constipation may occur as well. The severity of symptoms depends on the extent of the infection and complications.

What causes diverticulosis?

The dominant theory is that a low fibre diet is the main cause of diverticular disease. This disease is common in developed and industrialised countries such as Australia, USA and the UK where low fibre diets are common. The disease is rare in countries such as Asia and Africa where people eat high fibre vegetable diets. Fibre is the part of the fruits, vegetables and grains that the body cannot digest. Some fibre dissolves easily in water (soluble fibre) where some fibre passes almost unchanged through the intestine (insoluble fibre). Both kinds of fibre help to make the stool soft and easy to pass and therefore help to prevent constipation. Constipation makes the muscles strain to move stool that is too hard and it is one of the main causes of increased pressure in the colon. Excess pressure may cause weak spots in the colon to bulge out and become diverticuli.

What causes diverticulitis?

Diverticulitis occurs when diverticula become infected or inflamed. The exact cause is uncertain and it may begin when stool or bacteria are caught in the diverticula. Some people relate certain attacks to dietary indiscretion such as consuming nuts or foods with seeds or pips but there is no consistent evidence that certain foods precipitate attacks.

How is diverticulosis diagnosed?

To confirm diverticulosis some form of imaging or endoscopic examination is usually required. As most people do not have symptoms, diverticulosis is often diagnosed through tests ordered for another ailment, e.g. rectal bleeding.

How is diverticulitis diagnosed?

As mentioned diverticulitis is a complication of diverticulosis and occurs when diverticula become infected or inflamed. The infection/inflammation in the bowel will frequently cause a rise in CRP (an inflammatory marker found in the blood) and if pain is severe then a CT scan carried out on a new generation scanner will help. Ideally this scan should be reviewed by an experienced abdominal radiologist where the tell tale signs, i.e. streaking of the mesentery will be observed. This examination also has the advantage of ruling out other complications such as abscess formation or perforation.

Are there other complications of diverticulosis apart from infection?

  • Bleeding
    This is a rare complication but is usually dramatic when it occurs. The patient frequently describes sitting on the toilet and blood appears as if a 'tap was turned on'. As this symptom is often dramatic patients frequently seek emergency attention and usually urgent hospital admission is required. It is believed that bleeding occurs when a small blood vessel in a diverticula weakens and bursts. The vast majority of this type of bleeding settles spontaneously but occasionally an emergency colonoscopy with sclerotherapy (injection into the bleeding vessel)or surgery may be necessary.
  • Sepsis
    Perforation and peritonitis: while infection causing diverticulitis will usually present with pain occasionally symptoms are mild and ignored by the patient until their general condition deteriorates. This may mean an abscess is formed. An abscess is an infected area with pus which may cause swelling and destroy tissue. As tissues are destroyed, perforations will form and this may allow pus to leak out of the colon into the abdominal area. Small abscesses may respond to conservative treatment with intravenous antibiotics, bed rest and a liquid or low residue diet. Large abscesses may require surgery. If a large abscesses ruptures prior to hospital admission then an emergency operation may be called for.
  • Fistula
    This is an abnormal connection between the tissue of two organs. This occurs when infected tissue comes into contact with another organ within the abdomen causing them to stick together. If they heal that way then a fistula may form. The organs usually involved are the bladder, small intestine and occasionally the vagina. This complication will usually require surgery.
  • Intestinal obstruction
    Scarring caused by infection may lead to a partial or total blockage of the large intestine. When this happens the colon is unable to move bowel contents normally. If the obstruction is total then emergency surgery may be necessary. If the blockage is only partial then surgery can be carried out on a more planned basis.

Treatment of diverticulitis

Generally the treatment will be aimed at clearing up infection and inflammation, resting the colon and preventing or minimising complications. An attack of diverticulitis without complications may respond to antibiotics within a few days if treated early. Recommended antibiotics include Amoxycillin, Keflex, Metronidazole and Augmentin.

If the attack is severe then hospital admission may be required for intravenous antibiotics.

When is surgery necessary?

Most patients will only suffer from one attack and it is rare for these to recur. If the attacks are severe or frequent or associated with significant complications such as abscess formation then surgery may be advised. If patients have a well documented attack of diverticulitis before the age of 55, i.e. with raised CRP or CT scan changes then surgery may be advised even after a single attack. In these patients there is a concern that attacks will recur, particularly in later life when their fitness to undergo surgery may be less than optimal. The surgery usually involves a sigmoid resection, the affected part of the colon is removed and the remaining sections are joined back together. This aims to keep attacks from recurring and to prevent complications.

Surgery may also be recommended for significant complications, e.g. large abscess, fistula or obstruction.

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