Coeliac disease


Also known as: Coeliac sprue, gluten-sensitive enteropathy
Last Review Date: June 4, 2017


What is coeliac disease? 

Coeliac disease is an autoimmune disease characterised by an inappropriate immune response to gluten. Gluten is a protein found in wheat, similar proteins are found in barley and rye and to a lesser extent in oats. This response leads to inflammation of the small intestine and to damage and destruction of the villi that line the intestinal wall. The villi are projections, small tissue folds that increase the surface area of the intestine and allow nutrients, vitamins, minerals, fluids, and electrolytes to be absorbed into the body. When a susceptible person is exposed to gluten, their body produces autoantibodies that act against constituents of the intestinal villi. As long as the person continues to be exposed to the proteins, they will continue to produce these autoantibodies. When villi are damaged or destroyed, the body is much less capable of absorbing food including iron and vitamins. They may begin to develop symptoms associated with malnutrition and malabsorption. Malnutrition causes weight loss in adults and growth delay and failure to gain weight in children. Malabsorption causes diarrhoea and foul smelling bowel motions that float and have a greasy appearance because of the unabsorbed fats and oils in them.

Found throughout the world, coeliac disease is most prevalent in those of European descent. A recent Australian study found that the prevalence of coeliac disease in the Australian population may be as high as 1 in 70 people, though this is likely to be an overestimate as diagnosis was not confirmed by biopsy in all cases. The majority of people in this study were undiagnosed and had mild or no symptoms. Another recent UK study found a prevalence of diagnosed cases of coeliac disease of 1 in 420 people and cites three studies in the UK in different areas which found a total prevalence of diagnosed and undiagnosed coeliac disease of about 1 in 100 people. Coeliac disease can affect people of any age but is more common in infants and in those in their 30s and 40s. About 20% of those with coeliac disease are over 60 years old. It is somewhat more common in women than men. The development of coeliac disease is thought to be due to an inherited tendency that is triggered by an environmental, emotional, or physical event although the exact mechanism is not fully understood. According to the National Digestive Diseases Information Clearinghouse, about 5-15% of first-degree relatives (parent, sibling, or child) of a coeliac disease patient will also have the condition.


Signs and Symptoms

US studies suggest that only about 3% of people with coeliac disease have been diagnosed. In part, this is because symptoms may vary widely from person to person. According to the US Coeliac Support Association, only about 10% of those with coeliac disease will have typical malabsorption symptoms. About 40% will have less typical symptoms and as many as 33% may not have any associated symptoms. The manifestations of coeliac disease tend to vary with a person's age and stage of development. Since the same symptoms are present in a variety of other conditions, a diagnosis of coeliac disease may be missed or delayed -- sometimes for years.

Signs and symptoms of coeliac disease include:

  • Abdominal pain and distension
  • Iron deficiency anaemia that does not respond to iron supplements
  • Bleeding tendency
  • Bloody stool
  • Bone and joint pain
  • Changes in dental enamel
  • Diarrhoea
  • Fatigue
  • Flatulence
  • Greasy, foul-smelling stools
  • Mouth ulcers
  • Vomiting
  • Weakness
  • Weight loss

Some of these symptoms are seen in other conditions, including food allergies.

Children with coeliac disease may experience failure to thrive, delayed growth and development, delayed onset of puberty, and short stature. Adults with coeliac disease may also experience infertility. Many people with coeliac disease have dermatitis herpetiformis, a disease that causes itchy blisters on the skin. There is also an increased risk for developing osteoporosis and lymphoma, a form of cancer.


Tests

Most coeliac disease testing involves the detection of specific autoantibodies. It is performed to diagnose and monitor coeliac disease, primarily in symptomatic people. Testing may include:

  • Anti-tissue Transglutaminase (anti-tTG) Antibodies, IgA: This is the most sensitive and specific blood test for coeliac disease and is typically the initial test performed.
  • Anti-tTG, IgG: The test for the IgG class of anti-tTG is less sensitive and specific than the IgA class but is not affected by IgA deficiency, which is more common in those with coeliac disease.
  • Deamidated Gliadin Peptide (DGP) Antibodies, IgA: a relatively new test that may be positive in some people with coeliac disease who are anti-tTG negative; DGP IgG testing along with anti- tTG IgA is recommended in Australia.
  • Anti-Gliadin Antibodies (AGA), IgG and IgA: an autoantibody against the gliadin portion of gluten; guidelines by the American College of Gastroenterology published in 2013 do not recommend this test for the primary detection of coeliac disease due to concerns with its accuracy.
  • Anti-Endomysial Antibodies (EMA), IgA: less common, provides essentially the same information as anti-tTG.
  • Anti-Reticulin Antibodies (ARA), IgA: less common; not as specific or sensitive as other tests.
  • Anti-Actin IgA (F-actin): less common; may indicate increased intestinal damage.

To confirm a diagnosis of coeliac disease, a biopsy of the small intestine is examined to detect damage to the intestinal villi.

Genetic tests that look for the markers that are strongly associated with coeliac disease are available but not routinely ordered. These tests include the Human Leukocyte Antigen (HLA) markers DQ2 and DQ8. A positive result does not diagnose coeliac disease since greater than 40% of the Australian population also carry these markers but do not have the disease. A negative result, however, can essentially rule out coeliac disease in those individuals for whom results of other tests, including biopsy, are unclear. These tests are most useful for family members of individuals with the disease who fall into a high risk category and for those with other diagnostic test results that are inconclusive.

Other tests may be ordered to evaluate the severity of the disease and the extent of a person's malnutrition, malabsorption, and organ involvement. These may include:

 

Non-laboratory testing: X-rays of the intestines after barium ingestion may show characteristic findings that indicate intestinal damage.


Treatment

People with coeliac disease must follow a lifelong gluten-free diet. This usually requires consultation with a dietician and a careful review of food ingredients to be successful. Once all forms of wheat, rye, barley and often oats, have been removed from the diet, autoantibody levels will begin to fall and the intestine will heal. The Australian Coeliac Association states that; “1 in 5 people with coeliac disease have an autoimmune reaction to the avenin in oats. The only way people who react to oats can be confirmed is by biopsy before and after a period eating oats. This is not practical or desirable for many people so the approach often taken in Australia is that oats are not safe for people on a gluten free diet.”

While most if not all of the intestinal damage caused by coeliac disease is reversible, some effects of prolonged malnutrition and malabsorption – such as short stature and weakened bones – may be permanent. It is important to detect and treat coeliac disease as soon as possible, especially in young children. Coeliac disease should be considered in infants who are not thriving, since foods with gluten are common and coeliac autoantibodies may begin to develop shortly after a child switches from milk to solid foods.

In most cases, those on a strict gluten-free diet will remain healthy and symptom-free and can live a relatively normal life. However, if a person begins to consume gluten-containing foods again, within a short period of time both the symptoms of coeliac disease and the damage to intestinal villi will return. Even people with few or no symptoms can have intestinal damage and, over time, may develop complications, such as nutritional deficiencies and decreased bone mineral density. Coeliac disease when uncontrolled is associated with an increased risk of non-Hodgkins lymphoma.

A small percentage of those affected by coeliac disease do not respond to a gluten-free diet and/or may have irreversible damage to the intestine. These people may require additional medical interventions and nutritional support.


Related Pages

On this site
Tests: Coeliac disease tests, Total Protein, Albumin, Calcium, Vitamin D, FBC, Autoantibodies
Conditions: Autoimmune disorders, Malnutrition, Malabsorption

Elsewhere on the web
Coeliac Society of Australia
Healthdirect Australia: Coeliac disease and gluten intolerance

MedlinePlus Health Information: Celiac Disease 
National Digestive Diseases Information Clearinghouse: Celiac Awareness Campaign 
Celiac Support Association CSA/USA On-Line 
MayoClinic.com: Celiac disease diet, How do I get enough grains? 
Familydoctor.org: Celiac disease  
Kidshealth.org: Celiac disease  
North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition: Gluten-Free Diet Guide for Families (pdf)