Coeliac disease

Coeliac disease is a chronic autoimmune disease in which the immune system targets the body when it is exposed to gluten, a dietary protein found in wheat, barley and rye. This causes inflammation and damage in the gut (small intestine), preventing the body from absorbing nutrients (Payne, 2022).

Many people wrongly believe coeliac disease is a food allergy or intolerance.

One person in 100 has coeliac disease, but only one-third (36%) have a formal diagnosis. Some 500,000 are living with the disease but do not know. A person’s chances of having coeliac disease increases to 1 in 10 if they have a parent or sibling with it (Coeliac UK, 2022a).

Coeliac disease is more prevalent in people with other autoimmune diseases and chromosomal syndromes. It is most commonly diagnosed between the ages of 50 and 59, although it can affect anybody at any age (Payne, 2022).

Symptoms of coeliac disease include a variety of gastric problems that may be different depending on the patient’s age (Payne, 2022).

In babies, symptoms will begin when they start eating solid foods containing gluten. The infant may have foul-smelling diarrhoea and vomit frequently. Their stools might be pale, the abdomen swollen, and the baby may not thrive (Payne, 2022).

In children, symptoms may be difficult to spot if they are mild. As such, poor or delayed growth is often the first sign, because they don’t absorb dietary nutrients. They may develop anaemia and other nutrient deficiencies. The child may have diarrhoea and foul-smelling stools. Left undiagnosed and untreated, coeliac disease can delay puberty (Payne, 2022).

In adults, symptoms include:

• persistent gut problems
  • irritable bowel syndrome (coeliac disease is often misdiagnosed as IBS)
  • abdominal pain
  • flatulence
  • bloating
  • diarrhoea
• lethargy and feeling weak, due to nutrient deficiencies
• anaemia
• recurrent mouth ulcers
• weight loss

It is not known exactly why some people are sensitive to gluten. Coeliac disease is an autoimmune disease, in which the body makes antibodies against gluten. When the person consumes gluten-containing food or drink, their gut mistakes the gluten for some kind of bacteria, virus or other foreign body.

This triggers the antibodies to attack the body’s tissue – in this case, the lining of the gut. The gut becomes inflamed and damaged, which in turn flattens the millions of tiny tubes covering the surface of the gut, called villi (Coeliac UK, 2022b).

In a healthy gut, these villi increase the gut’s surface area enabling it to better digest food. In coeliac disease, with the villi flattened as a result of inflammation, the gut’s ability to digest food is diminished – and the body cannot absorb dietary nutrients.

Other long-term conditions

It is not known whether associated health conditions directly

Patients with symptoms of coeliac disease should not eliminate gluten from their diet before a formal diagnosis. Coeliac disease will be suspected in patients who present with symptoms, together with the presence of a family history and risk factors.

Next, the patient will have coeliac serology testing to check for antibodies (serum immunoglobulin (Ig)A tissue transglutaminase antibodies (tTGA) and total IgA). The results of this test do not constitute a firm diagnosis, but indicate further assessment is needed (NICE, 2020c).

It is important that the patient consumes gluten in at least one meal a day for at least 6 weeks before the blood tests (NICE, 2020c).

Typically, if the serology tests suggest coeliac disease the patient would be referred to a gastroenterology specialist and have an endoscopic intestinal biopsy to confirm or rule out coeliac disease (NICE, 2020c).

The British Society of Gastroenterologists published interim guidance in the wake of

Treatment for coeliac disease is total, lifelong exclusion of gluten from the diet. Some people with coeliac disease also react to oats. This may be because oats contain a dietary protein called avenin, which appears to trigger a similar reaction, in some people, to gluten. Oats can sometimes trigger an immune response because they are contaminated with gluten from manufacturing processes (NHS, 2019b).

Gluten is present in barley, wheat, rye, semolina, durum, couscous and spelt. Gluten-containing foods include:

• bread
• pasta
• cereals
• cakes
• biscuits and crackers
• pies
• sauces and gravy

Patients may also be advised to take iron, vitamin and calcium supplements to replace nutrients, especially in the 6 weeks following diagnosis while the lining of the gut recovers (Payne, 2022).

Some people with coeliac disease develop complications despite adhering to a completely gluten-free diet but usually, complications occur if patients are not strictly following their diet.

Complications include returning symptoms described above, as well as (NHS, 2019c):

• malabsorption
  • iron-deficient anemia
  • B12-deficient anaemia
  • folate-deficient anaemia
  • osteoporosis
• malnutrition
• lactose intolerance
• pregnancy complications – premature birth, low birth weight
• weakness of tooth enamel
• lymphoma of the gut (rare)

People with coeliac disease also have a higher risk of other autoimmune diseases, including type 1 diabetes, hypothyroidism, Sjögren’s syndrome (characterised by dry eyes and mouth) and primary biliary cholangitis (damage to the bile ducts and liver, causing cirrhosis) (Payne, 2022).

The neurological conditions gluten ataxia (difficulty with balance and coordination), gluten neuropathy (numbness, tingling in the limbs) and gluten encephalopathy (brain disorder causing headaches and poor cognition and memory) are slightly more common in people with coeliac disease. Research into the link between these conditions

References

British Society of Gastroenterology. BSG Interim Guidance: COVID-19 specific non-biopsy protocol for those with suspected coeliac disease. 2022. www.bsg.org.uk/covid-19-advice/covid-19-specific-non-biopsy-protocol-guidance-for-those-with-suspected-coeliac-disease/ (accessed 22 July 2022)

Coeliac UK. About coeliac disease. 2022a. www.coeliac.org.uk/information-and-support/coeliac-disease/about-coeliac-disease/ (accessed 22 July 2022)

Coeliac UK. Causes. 2022b. www.coeliac.org.uk/information-and-support/coeliac-disease/about-coeliac-disease/causes/ (accessed 22 July 22)

Coeliac UK. Genetics – at a glance. 2022c. www.coeliac.org.uk/information-and-support/coeliac-disease/about-coeliac-disease/causes/genetics/ (accessed 22 July 22)

National Institute for Health and Care Excellence. Coeliac disease: diagnosis (CKS) 2020a. https://cks.nice.org.uk/topics/coeliac-disease/diagnosis/diagnosis/ (accessed 1 December 2022)

National Institute for Health and Care Excellence. Coeliac disease: what are the causes? (CKC) 2020b. https://cks.nice.org.uk/topics/coeliac-disease/background-information/causes/ (accessed 1 December 2022)

National Institute for Health and Care Excellence. Coeliac disease: How should I assess a person with suspected coeliac disease? (CKS) 2020c. https://cks.nice.org.uk/topics/coeliac-disease/diagnosis/assessment/ (accessed 1 December 2022)

NHS. Symptoms – coeliac disease. 2019a. www.nhs.uk/conditions/coeliac-disease/symptoms/ (accessed 22 July 2022)

NHS. Treatment – coeliac disease. 2019b. www.nhs.uk/conditions/coeliac-disease/treatment/ (accessed 22 July 2022)

NHS. Complications – coeliac disease. 2019c. www.nhs.uk/conditions/coeliac-disease/complications/

Payne J, Coeliac disease. 2018.