Medical diagnosis: coeliac disease

In people with coeliac disease, consuming gluten damages the lining of the small intestine. For them to live without any symptoms, they need to follow a lifelong gluten-free diet. For that reason, a reliable medical diagnosis is very important – and also because other conditions can also be triggered by gluten-containing cereal.

Coeliac disease is an autoimmune disorder which can occur at any age and which can manifest through a wide range of symptoms. The condition is triggered by gluten, which is contained in cereals such as wheat, rye and barley. In people with coeliac disease, consuming gluten-containing foods leads to chronic inflammation of the small intestine.

Normally, the lining (mucosa) of the small intestine has millions of tiny projections known as 'villi' which enlarge the surface of the small intestine – and in so doing increase potential nutrient uptake. In people with coeliac disease, the intestinal mucosa is so badly damaged by the inflammation that the villi become flattened and sufficient nutrients are no longer absorbed in the body. This can lead to an undersupply of vitamins and minerals, such as vitamin B12, iron or calcium. Untreated coeliac disease can also cause secondary conditions such as anaemia or osteoporosis.

However, if people with coeliac disease follow a strict gluten-free diet, the normal intestinal mucosa recovers and they can lead a symptom-free life. For this reason, a reliable medical diagnosis is very important. However, to ensure that the diagnosis is correct, it is important not to start on a gluten-free diet before the exam is performed. Otherwise, the results may be distorted. At the doctor's, patients with suspected coeliac disease are first given a blood test to detect antibodies specific to coeliac disease. In order to ensure that this test is meaningful, total immunoglobulin A (‘IgA’) is also determined. If antibodies are detected, a biopsy of the small intestine is performed to confirm the diagnosis. To this end, a tiny specimen of the mucosa is taken endoscopically and examined under a microscope. If abnormal changes to the intestinal mucosa are detected, the patient is diagnosed with coeliac disease.

In patients with coeliac disease, a reliable medical diagnosis is also very important because other conditions triggered by gluten-containing cereal exist as well:

• In individuals with a wheat allergy, the immune system reacts to what are usually harmless components of the wheat. While these individuals thus have to follow a wheat-free diet, they can consume other gluten-containing cereals without any trouble.
• The symptoms of gluten and wheat sensitivity are associated with hypersensitivity to gluten and wheat ingredients. If coeliac disease and wheat allergy have been ruled out as reasons for the symptoms, the diagnosis of gluten and wheat sensitivity is based on decrease in symptoms in response to the gluten-free diet.
• If coeliac disease, gluten and wheat sensitivity and wheat allergy are ruled out, irritable bowel syndrome may also be considered as a cereal-associated disorder.  Some people with IBS respond to a diet that is low in ‘FODMAPs’ (short-chain fermentable carbohydrates). Wheat is a main contributor of FODMAPs in the western diet.