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19 March, 2010

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Collagenous colitis

Collagenous colitis is inflammation of the colon, the last portion of the digestive tract that ends at the rectum and anus. The most common symptom is chronic watery, non-bloody diarrhoea. In severe cases, the patient may be going to the toilet up to 20 times a day.

Collagenous colitis is a rare condition that affects about four people in every 10,000. It tends to develop in people aged over 40 years. Women outnumber men 20 to one, for reasons that are not clear. There is no cure but lifestyle changes and medical treatment can manage the symptoms in most cases. Collagenous colitis is sometimes called microscopic colitis.

Symptoms
The symptoms and signs may include:

Sudden onset of chronic watery diarrhoea
The diarrhoea may be relentless or may come and go in regular cycles
The diarrhoea does not contain blood or pus
Bowel incontinence
Abdominal pain and nausea
Abdominal bloating
Persistent fatigue
Weight loss.

Possible complications
Without treatment, possible complications may include:

Dehydration
Malabsorption of food nutrients
Malnutrition.

The collagen layer is affected
The inside surface of the colon is lined with epithelial cells and is called the epithelium. The epithelium absorbs water from faeces. When a person has collagenous colitis, the epithelium is not inflamed or damaged, which is why the diarrhoea doesn’t contain blood or pus. However, the epithelium harbours greater than normal amounts of certain immune system cells called lymphocytes.

Beneath the epithelium is a layer of tough connective tissue made up of collagen (a type of protein that gives strength to many structures including tendons, bones and skin). Collagenous colitis gets its name because the inflammation takes place within the collagen layer of the colon, which becomes thickened.

The cause is unknown
Collagenous colitis seems to occasionally run in families, which suggests a genetic component to the condition. However, doctors aren’t sure what causes the inflammation. One theory proposes that an unknown virus or bacterium is to blame. Another theory is that collagenous colitis is a type of autoimmune disorder, which means the immune system attacks a healthy part of the body by mistake. Some people with collagenous colitis also have other autoimmune disorders such as rheumatoid arthritis, scleroderma or Sjogren’s syndrome.

Lymphocytic colitis
Lymphocytic colitis is similar to collagenous colitis; in fact, some researchers believe them to be different stages of the same condition. They are sometimes collectively called ‘microscopic colitis’, since diagnosis of both conditions requires the examination of colon tissue under a microscope.

While lymphocytic colitis causes the same symptoms as collagenous colitis, the condition does not involve the collagen layer. Lymphocytic colitis gets its name from the characteristic build-up of lymphocytes within the colon’s epithelium.

Diagnosis
The symptoms of collagenous colitis are similar to other gastrointestinal illnesses such as irritable bowel syndrome, Crohn’s disease and ulcerative colitis. Diagnosis may include:

Medical history
Physical examination
Tests (such as a stool culture) to rule out other gastrointestinal diseases
Colonoscopy – the use of a slender viewing tube inserted into the colon via the anus; to view inside the colon.
Biopsy – the removal of a small tag of tissue for examination in a laboratory; changes, including an abnormally thick collagen layer, are visible under the microscope.

Treatment
There is no cure but treatment can manage the symptoms. Options may include:

Watchful waiting – some patients with collagenous colitis improve without any treatment, for reasons unknown. The doctor may like to wait and see for a week or two before prescribing any medications.
Dietary changes – some foods and drinks aggravate diarrhoea. Your doctor may advise you to cut down on fatty or spicy foods, milk products, alcohol and caffeine. Avoid gas-promoting products such as beans, cabbage and fizzy drinks.
Switching medicines – some evidence suggests that non-steroidal anti-inflammatory drugs, including aspirin and ibuprofen, can worsen collagenous colitis. Your doctor may recommend that you trial different medicines, if possible, to see if symptoms improve.
Anti-diarrhoea medication – to slow the passage of food waste through the colon.
Other medications – if the above measures don’t seem to help, the doctor may suggest stronger medications such as corticosteroids to help ease the symptoms.
Surgery – in very rare cases, the chronic diarrhoea cannot be brought under control and surgery is needed. Diseased sections of the colon may be removed. As a last resort, the surgeon may perform an operation called a diverting ileostomy, which involves re-routing the last section of the small intestine (ileum) through an artificially created hole in the abdominal wall.

Where to get help

Your doctor
Gastroenterologist

Things to remember

Collagenous colitis is inflammation of the colon, the last portion of the digestive tract that ends at the rectum and anus.
The most common symptom is chronic watery, non-bloody diarrhoea.
There is no cure but dietary changes and medical treatment, including drugs, can manage the symptoms in most cases.

You might also be interested in:
Colonoscopy.
Crohn's and colitis.
Crohn's and colitis - complications.
Crohn's and colitis - dietary considerations.
Stoma after ileostomy or colostomy.

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