COELIAC DISEASE

What is coeliac disease?

Coeliac disease is a digestive disease that damages the small intestine and interferes with absorption of nutrients from food. People who have coeliac disease cannot tolerate a protein called gluten, found in wheat, rye, and barley. Gluten is found mainly in foods, but is also found in products we use every day, such as stamp and envelope adhesive, medicines, and vitamins.

When people with coeliac disease eat foods or use products containing gluten, their immune system responds by damaging the small intestine. The tiny, fingerlike protrusions lining the small intestine are damaged or destroyed. Called villi, they normally allow nutrients from food to be absorbed into the bloodstream. Without healthy villi, a person becomes malnourished, regardless of the quantity of food eaten.

Because the body's own immune system causes the damage, coeliac disease is considered an autoimmune disorder. However, it is also classified as a disease of malabsorption because nutrients are not absorbed. Coeliac disease is also known as coeliac sprue, nontropical sprue, and gluten-sensitive enteropathy.

Coeliac disease is a genetic disease, meaning it runs in families. Sometimes the disease is triggered-or becomes active for the first time-after surgery, pregnancy, childbirth, viral infection, or severe emotional stress.

What are the symptoms of coeliac disease?

Coeliac disease affects people differently. Symptoms may occur in the digestive system, or in other parts of the body. For example, one person might have diarrhoea and abdominal pain, while another person may be irritable or depressed. In fact, irritability is one of the most common symptoms in children.

Symptoms of coeliac disease may include one or more of the following:

• gas
• recurring abdominal bloating and pain
• chronic diarrhoea
• pale, foul-smelling, or fatty stool
• weight loss / weight gain
• fatigue
• unexplained anaemia (a low count of red blood cells causing fatigue)
• bone or joint pain
• osteoporosis, osteopaenia
• behavioural changes
• tingling numbness in the legs (from nerve damage)
• muscle cramps
• seizures
• missed menstrual periods (often because of excessive weight loss)
• infertility, recurrent miscarriage
• delayed growth
• failure to thrive in infants
• pale sores inside the mouth, called aphthous ulcers
• tooth discoloration or loss of enamel
• itchy skin rash called dermatitis herpetiformis

A person with coeliac disease may have no symptoms. People without symptoms are still at risk for the complications of coeliac disease, including malnutrition. The longer a person goes undiagnosed and untreated, the greater the chance of developing malnutrition and other complications. Anaemia, delayed growth, and weight loss are signs of malnutrition: The body is just not getting enough nutrients. Malnutrition is a serious problem for children because they need adequate nutrition to develop properly.

Why are coeliac symptoms so varied?

Researchers are studying the reasons coeliac disease affects people differently. Some people develop symptoms as children, others as adults. Some people with coeliac disease may not have symptoms, while others may not know their symptoms are from coeliac disease. The undamaged part of their small intestine may not be able to absorb enough nutrients to prevent symptoms.

The length of time a person is breastfed, the age a person started eating gluten-containing foods, and the amount of gluten containing foods one eats are three factors thought to play a role in when and how coeliac appears. Some studies have shown, for example, that the longer a person was breastfed, the later the symptoms of coeliac disease appear and the more uncommon the symptoms.

How is coeliac disease diagnosed?

Recognising coeliac disease can be difficult because some of its symptoms are similar to those of other diseases. In fact, sometimes coeliac disease is confused with irritable bowel syndrome, iron-deficiency anaemia caused by menstrual blood loss, Crohn's disease, diverticulitis, intestinal infections, and chronic fatigue syndrome. As a result, coeliac disease is commonly under diagnosed or misdiagnosed.

Recently, researchers discovered that people with coeliac disease have higher than normal levels of certain autoantibodies in their blood. Antibodies are protective proteins produced by the immune system in response to substances that the body perceives to be threatening. Autoantibodies are proteins that react against the body's own molecules or tissues. To diagnose coeliac disease, physicians will usually test blood to measure levels of

• Immunoglobulin A (IgA)
• anti-tissue transglutaminase (tTGA)
• IgA anti-endomysium antibodies (AEA)

Before being tested, one should continue to eat a regular diet that includes foods with gluten, such as breads and pastas. If a person stops eating foods with gluten before being tested, the results may be negative for coeliac disease even if coeliac disease is actually present.

If the tests and symptoms suggest coeliac disease, the doctor will perform a small bowel biopsy. During the biopsy, the doctor removes a tiny piece of tissue from the small intestine to check for damage to the villi. To obtain the tissue sample, the doctor eases a long, thin tube called an endoscope through the mouth and stomach into the small intestine. Using instruments passed through the endoscope, the doctor then takes the sample.

Screening

Screening for coeliac disease involves testing for the presence of antibodies in the blood in people without symptoms. Americans are not routinely screened for coeliac disease. Testing for coeliac-related antibodies in children less than 5 years old may not be reliable. However, since coeliac disease is hereditary, family members, particularly first-degree relatives-meaning parents, siblings, or children of people who have been diagnosed-may wish to be tested for the disease. About 5 to 15 percent of an affected person's first-degree relatives will also have the disease. About 3 to 8 percent of people with type 1 diabetes will have biopsy-confirmed coeliac disease and 5 to 10 percent of people with Down syndrome will be diagnosed with coeliac disease.

What is the treatment?

The only treatment for coeliac disease is to follow a gluten-free diet. When a person is first diagnosed with coeliac disease, the doctor usually will ask the person to work with a dietitian on a gluten-free diet plan. A dietitian is a health care professional who specializes in food and nutrition. Someone with coeliac disease can learn from a dietitian how to read ingredient lists and identify foods that contain gluten in order to make informed decisions at the grocery store and when eating out.

For most people, following this diet will stop symptoms, heal existing intestinal damage, and prevent further damage. Improvements begin within days of starting the diet. The small intestine is usually completely healed in 3 to 6 months in children and younger adults and within 2 years for older adults. Healed means a person now has villi that can absorb nutrients from food into the bloodstream.

In order to stay well, people with coeliac disease must avoid gluten for the rest of their lives. Eating any gluten, no matter how small an amount, can damage the small intestine. The damage will occur in anyone with the disease, including people without noticeable symptoms. Depending on a person's age at diagnosis, some problems will not improve, such as delayed growth and tooth discoloration.

Some people with coeliac disease show no improvement on the gluten-free diet. The condition is called unresponsive coeliac disease. The most common reason for poor response is that small amounts of gluten are still present in the diet. Advice from a dietitian who is skilled in educating patients about the gluten-free diet is essential to achieve best results.

Rarely, the intestinal injury will continue despite a strictly gluten-free diet. People in this situation have severely damaged intestines that cannot heal. Because their intestines are not absorbing enough nutrients, they may need to directly receive nutrients into their bloodstream through a vein (intravenously). People with this condition may need to be evaluated for complications of the disease. Researchers are now evaluating drug treatments for unresponsive coeliac disease.

What are the complications of coeliac disease?

Damage to the small intestine and the resulting nutrient absorption problems put a person with coeliac disease at risk for malnutrition and anaemia as well as several diseases and health problems.

• Lymphoma and adenocarcinoma are cancers that can develop in the intestine.
• Osteoporosis is a condition in which the bones become weak, brittle, and prone to breaking. Poor calcium absorption contributes to osteoporosis.
• Miscarriage and congenital malformation of the baby, such as neural tube defects, are risks for pregnant women with untreated coeliac disease because of nutrient absorption problems.
• Short stature refers to being significantly under-the-average height. Short stature results when childhood coeliac disease prevents nutrient absorption during the years when nutrition is critical to a child's normal growth and development. Children who are diagnosed and treated before their growth stops may have a catch-up period