Diverticulosis and diverticulitis

About diverticular disease

Diverticulosis occurs when small defects in the muscle of the wall of the large intestine or 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.

Despite having some symptoms in common, diverticular disease isn’t associated with more serious conditions, such as bowel cancer. However, diverticulitis is often a medical emergency, requiring immediate medical attention and, frequently, admission to hospital. Mild attacks can be treated at home, but should always be assessed promptly.

Causes of diverticular disease

Diverticulosis is extremely common. Old age and diet may be the most important risk factors. More than half of all adults over the age of 70 have the condition. Most of these people are unaware that they have diverticulosis.

Diverticulosis is less common in people under 50. Studies appear to show that diverticulosis became more common in the 20^th century. It is also more common in ‘Western’ nations including North America, Europe and Australia. It is less common in Asia and very uncommon in Africa.

Discovery of these facts led to the theory that the low-fibre diet common in Western nations may be important. Animal studies show that this theory is possible. It has also been shown that vegetarians less commonly develop diverticulosis. Exactly how a low-fibre diet may cause diverticulosis is not known.

Analysis of large-scale epidemiological studies has found that people with higher overall fibre intake have lower incidence of diverticulitis, the main complication of diverticular disease. The type of dietary fibre may be important, with grains, cereals and fruits beneficial while vegetable intake may not be beneficial.

There may also be genetic causes. Western people develop diverticulosis in the last third of the colon, while people in Asian countries – such as Japan, Taiwan and Singapore – generally develop diverticulosis in the first section of the colon. In the Japanese population living in Hawaii, the risk of diverticulosis is higher than those living in Japan. However, when diverticulosis develops in these people, it is still in the ‘Japanese’ location – the first third of the colon.

Analysis of familial cases of diverticulitis has identified at least 2 genes associated with this condition, and one of these (TNFSF15) has been shown to be associated with diverticulitis in multiple studies.

Diverticulitis seems to occur when a small puncture develops in the diverticular wall. This causes a small infection to develop, often forming an abscess.

Symptoms of diverticulosis

Diverticulosis is usually asymptomatic (has no symptoms). However, 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 bleeding can sometimes be heavy if a diverticulum gets inflamed or is near a blood vessel
• anaemia from repeated bleeding may occur.

Many of these symptoms are similar to those of bowel cancer. Diverticulosis is more common, so these symptoms may be more likely to be due to diverticulosis than cancer. However, a specialist will usually assess these symptoms – your doctor will refer you.

Symptoms of diverticulitis

Symptoms of diverticulitis include:

• sharp pain, often located at a specific point – for example, in the lower left half of the abdomen
• fever
• distension (bloating) of the abdomen
• nausea and vomiting.

Complications of diverticular disease

Some of the possible complications of diverticular disease include:

• Abscess – untreated, diverticulitis may lead to an abscess (a ball of pus).
• Perforation – a weakened pocket of bowel wall may rupture. The contents of the bowel can then seep into the abdominal cavity. Symptoms include pain, high fever and chills. A perforated bowel is a medical emergency.
• Peritonitis – perforation can lead to peritonitis (infection of the membranes that line the abdominal cavity and abdominal organs). This complication is potentially life threatening.
• Haemorrhage – diverticula can be the source of haemorrhage. When bleeding occurs, it is important to exclude other causes. A person with diverticulosis can also get cancer.

Diagnosis of diverticular disease

Since diverticulosis is often asymptomatic (without symptoms), it tends to be discovered during examinations for other conditions such as colorectal cancer. Diverticulitis is usually diagnosed during an acute attack.

Tests to confirm the diagnosis of diverticular disease include:

• medical history – including dietary habits
• physical examination – including rectal examination
• colonoscopy – a slender flexible tube inserted into the anus so that the doctor can look at the entire length of the large intestine
• barium enema – a special contrasting dye flushed into the bowel via the anus and x-rays are taken
• 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 the presence of infections, which may mimic the symptoms of diverticulosis and diverticulitis.

Treatment for diverticulosis

For a person with diverticulosis, there is no proven way to prevent the formation of new diverticula. Treatment revolves around the settling of symptoms.

• A gradual switch to a diet with increased soluble fibre (green vegetables, oat bran and fibre supplements such as psyllium) usually leads to an improvement in bowel habit and mild symptoms.
• Short-term use of laxatives to treat and prevent constipation may be advised.
• Rarely, elective surgery is performed to remove seriously affected bowel segments when symptoms are disabling.
• One antibiotic (rifaximin) has been successful in randomised trials for those with more severe symptoms of diverticular disease. However, this drug is not rebated in Australia and is expensive.

Treatment for diverticulitis

Diverticulitis is often a medical emergency, requiring immediate medical attention and, frequently, admission to hospital. Mild attacks can be treated at home, but should always be assessed promptly. Treatment may include:

• no eating or drinking – intravenous fluids are given to rest the bowel
• antibiotics
• pain-relieving medication
• surgery – if the weakened sections of bowel wall have ruptured or become obstructed, or if the attack of infection fails to settle
• colostomy – if it isn’t possible to rejoin the healthy sections of bowel, a Hartman’s procedure may be performed and a colostomy bag fitted. This is more common if the surgery is performed as an emergency. The use of a colostomy is generally temporary and the bowel can be rejoined after 6 to 12 months, if health permits. This practice has been challenged by a randomised trial showing better outcomes in patients when the bowel was rejoined during emergency surgery rather than patients who were given Hartman’s procedures.
• the long-term use of a mild antibiotic – this is often necessary to prevent further attacks, but is generally not recommended.

Self-care suggestions for diverticular disease

Suggestions include:

• Increase your daily intake of fibre. Introduce fibre gradually to avoid unpleasant symptoms such as flatulence.
• Drink plenty of fluids to ensure your stools are soft, moist and easy to pass.
• Exercise regularly to encourage bowel function and peristalsis.

Where to get help

• Your GP (doctor)
• NURSE-ON-CALL Tel. 1300 60 60 24 – for expert health information and advice (24 hours, 7 days)
• Gastroenterologist
• Specialist surgeon
• Dietitians Australia