The presence of small pouches known as diverticula in the wall of the colon
- More common over the age of 50
- A low-fibre diet is a risk factor
- Gender and genetics are not significant factors
In diverticular disease, pea- or grape-sized pouches (diverticula) protrude from the wall of the large intestine, usually from the part of the colon closest to the rectum. The pouches form when parts of the wall of the intestine bulge outwards through weakened areas, often close to an artery. In many cases, the bulging of the intestinal wall is associated with persistent constipation and occurs when the pressure inside the intestine increases as the person strains to defecate. Sometimes, one or more pouches become inflamed, a condition known as diverticulitis.
About 1 in 3 people between the ages of 50 and 60 has diverticular disease, and it becomes increasingly common after the age of 60. However, more than three-quarters of affected people have no symptoms. The disease is strongly associated with a low-fibre diet, which can lead to constipation. The disease is very rare in developing countries, where fibre is a large part of the diet.
What are the symptoms?
Most people with diverticular disease are unaware of the condition because they have no symptoms. If symptoms are present, they may include:
Episodes of abdominal pain, especially in the lower left abdomen, that are relieved by a bowel movement or a release of intestinal wind.
Intermittent episodes of constipation and diarrhoea.
Occasional bright red bleeding from the rectum, which may be painless.
Diverticular disease is sometimes difficult to distinguish from irritable bowel syndrome, which has similar symptoms. If diverticulitis develops, the symptoms may become worse and be accompanied by:
Severe lower abdominal pain and tenderness in the abdomen.
Nausea and vomiting.
If you notice any change in your bowel habits or you have rectal bleeding, you should consult your doctor immediately because these symptoms may indicate a more serious underlying disease, such as colorectal cancer.
Are there complications?
If an inflamed diverticulum bursts, faeces and bacteria can spill into the abdominal cavity. As a result, an abscess may form next to the colon or peritonitis, an inflammation of the membrane that lines the abdominal cavity, may develop. Peritonitis is a potentially life-threatening condition.
An abnormal channel called a fistula may develop between a diverticulum and the bladder, resulting in pain, a more frequent urge to pass urine, or recurrent bladder infections (see Cystitis). In some women, a fistula may develop between a diverticulum and the vagina, causing faecal material to be discharged through the vagina. An inflamed diverticulum may also cause intestinal obstruction.
How is it diagnosed?
If your doctor suspects that you have diverticular disease, he or she may arrange for you to have a contrast X-ray in which a barium enema is used to highlight the shape of the intestines. If your symptoms include rectal bleeding, a colonoscopy may be carried out to examine the colon and exclude colorectal cancer. Sometimes, diverticular disease is found during an investigation for another disease.
What is the treatment?
Often, a high-fibre diet with plenty of fluids is the only treatment needed for diverticular disease, together with antispasmodic drugs (see Antispasmodic drugs and motility stimulants) if you have abdominal pain.
If you develop severe diverticulitis, you will be admitted to hospital and given intravenous fluids and antibiotics to treat bacterial infection. These measures produce improvements in most cases, and no further treatment is needed. However, surgery is sometimes necessary if you have severe rectal bleeding or if an abscess or a fistula develops. Anyone who has two or three attacks of diverticulitis within a few years is also likely to need surgery. The most common operation is a partial colectomy, in which the diseased part of the colon is removed and the healthy ends of the intestine are rejoined. At the same time, a temporary colostomy may be performed.
What is the prognosis?
The outlook for diverticular disease is generally good. If a high-fibre diet is adopted early enough, the condition is unlikely to progress. Among people with diverticulitis, 2 in 3 have only one attack, but in other people it recurs and surgery may be needed. About 2 in 10 people who experience bleeding will have a recurrence within the next few months to a year unless the problem is treated surgically.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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