Coeliac disease - causes, symptoms and measures for patients

What is coeliac disease and how does it develop?

Coeliac disease is a hereditary autoimmune disease caused by an increased sensitivity to gluten. Gluten is a protein found in wheat, rye and barley. The gliadin fraction of gluten in particular plays a central role in triggering this disease.

Genetic predisposition and immune response

In people with a genetic predisposition, contact with gluten leads to the activation of specific T-cells of the immune system. These T cells recognize and react to certain gluten peptide epitopes. This immune reaction causes inflammation in the mucous membrane of the small intestine.

Consequences of the inflammatory reaction

The inflammation triggered by the immune reaction leads to villous atrophy, damage to the villi of the small intestine. This villous atrophy impairs the intestine's ability to absorb nutrients, which leads to the typical symptoms of coeliac disease, such as diarrhea, abdominal pain and nutrient deficiency.

similar proteins in other cereals

In addition to wheat, rye and barley also contain proteins that can cause similar immunological reactions. Therefore, people with coeliac disease must also avoid these grains to prevent symptoms and maintain intestinal health.

Causes of coeliac disease:

• Genetics: celiac disease has a genetic component, and people with certain gene variants (HLA DQ2/DQ8) have an increased risk.
• Gluten consumption: The consumption of gluten-containing foods triggers the immunological reaction that leads to damage to the small intestine.

Epidemiology of coeliac disease

Spread of coeliac disease

Coeliac disease mainly affects people of northern European descent. Serological studies among blood donors, sometimes confirmed by biopsies, show that the prevalence of the disease in Europe is around 1 in 150 people. In some countries, such as Ireland and Italy, the prevalence is particularly high. In the USA, the prevalence is estimated at around 1 in 250 people, although in some regions a prevalence of up to 1 in 100 is suspected.

Risk groups and familial clustering

The disease often runs in families: About 10-20% of children who are direct relatives ("1st-degree relatives") of celiac disease patients also develop the disease. Women are affected twice as often as men, with a ratio of 2:1. Although coeliac disease is usually diagnosed in childhood, it can also occur later in life.

Connection with other diseases

Patients with certain other conditions have an increased risk of developing coeliac disease. These include

• Lymphocytic colitis
• Down syndrome
• Type 1 diabetes mellitus
• Autoimmune (Hashimoto's) thyroiditis

These comorbidities emphasize the need for careful monitoring and early diagnosis in people at risk.

Symptoms and signs of coeliac disease

Varied clinical presentation
The clinical presentation of coeliac disease is extremely varied and varies greatly from patient to patient. There is no typical presentation, which often makes diagnosis difficult. Some patients are asymptomatic or only show signs of nutritional deficiency, while others suffer from clear gastrointestinal symptoms.

Coeliac disease in children
In young children and adolescents, coeliac disease can manifest itself after the introduction of cereal products such as cereal flakes. Typical symptoms in affected children are

• Growth disturbances, apathy and anorexia
• Pallor and general hypotonia
• Bloated abdomen and muscle wasting
• Soft, voluminous, clay-colored and foul-smelling stools
• Anemia and growth disorders in older children

Coeliac disease in adults

• Gastrointestinal complaints
  • Abdominal pain
  • Meteorism (flatulence)
  • Intermittent diarrhea (occasional occurrence of diarrhea)
  • Constipation
  • Steatorrhea (greasy, pale, bulky and foul-smelling stools), which can vary in severity
• Weight loss: Unexplained weight loss despite normal or increased food intake, but rarely leading to underweight
• Anorexia (loss of appetite)
• Fatigue: Persistent fatigue and weakness.
• Anemia
• Inflammation of the tongue and corners of the mouth as well as aphthae
• Vitamin D or calcium deficiency, which can manifest as osteomalacia, osteopenia or osteoporosis
• Reduced fertility in both sexes
• absence of menstruation in women
• Dermatitis herpetiformis: Around 10% of patients develop dermatitis herpetiformis, a very itchy, papulovesicular skin rash. This occurs symmetrically on the extensor sides of the forearms, above the knees, on the buttocks, shoulders and head and can be triggered by food containing gluten.

Diagnosis of coeliac disease

When should you think about coeliac disease?

The diagnosis of coeliac disease should be considered when clinical and laboratory findings indicate malabsorption. A family history is also a valuable indicator. Especially in patients with iron deficiency without obvious gastrointestinal bleeding, celiac disease should be considered.

How is coeliac disease diagnosed?

The diagnosis is confirmed by a biopsy of the small intestine from the lower section of the duodenum. Typical histological findings are

• Villous atrophy
• Increased intraepithelial lymphocytes
• Crypt hyperplasia

These changes can also occur in other diseases such as tropical sprue, severe bacterial overgrowth of the small intestine (SIBO), eosinophilic enteritis, infectious enteritis (e.g. giardiasis) and lymphomas.

Role of serologic markers

Because the biopsy is not always specific, serologic markers are used for diagnosis:

• Anti-tissue transglutaminase antibodies (tTG)
• Anti-endomysium antibodies (EMA) have a sensitivity and specificity of over 90%.

These markers are particularly useful for screening high-risk individuals, including first-degree relatives and patients with commonly associated diseases. Positive test: If the serological test is positive, a diagnostic biopsy of the small intestine should be performed. Negative test: If the results are negative, celiac disease is highly unlikely if sufficient gluten has been consumed. Otherwise the test cannot be used.

monitoring dietary compliance

Antibody titres decrease in patients who follow a gluten-free diet. These tests are therefore also useful for monitoring dietary compliance.

Histocompatibility tests

Histocompatibility tests can be useful in selected clinical situations. over 95% of celiac disease patients have the HLA-DQ2 or HLA-DQ8 haplotypes. These tests can help to rule out celiac disease when biopsy and serologic markers do not match.

Further laboratory tests

Other pathologic laboratory values that should be investigated include:

• Anemia (iron deficiency in children, folic acid deficiency in adults)
• Low albumin
• Calcium, potassium and sodium
• Elevated alkaline phosphatase and prolonged prothrombin time
  • Malabsorption tests (not specific for coeliac disease): pathological D-xylose test (for severe ileum involvement)
  • Steatorrhea of 10-40 g/day

Tips and risks: In patients with iron deficiency without obvious gastrointestinal bleeding, coeliac disease should always be considered.

Treatment of coeliac disease

• Gluten-free diet: Strict avoidance of gluten is the most important treatment
• Supplements for all serious deficiencies
• Nutritional counseling: A nutritionist can help plan a balanced, gluten-free diet.
• Drug therapy: In some cases, medication may be prescribed to relieve symptoms.
• Regular check-ups: medical monitoring is important to ensure that the condition is well controlled.

Treatment for coeliac disease consists of a gluten-free diet (avoiding foods containing wheat, rye or barley). Gluten is so prevalent (e.g. commercially available soups, sauces, ice cream and hot dogs) that a patient needs a detailed list of foods to avoid. Patients are encouraged to consult a dietitian and join a celiac disease support group.

• IG Zöliakie der Deutschen Schweiz; www.zoeliakie.ch
• Association Romande de la Coeliakie; www.coeliakie.ch
• Ticino Coeliac Disease Association; www.celiachia.ch
• Patient organization Germany; www.dzg-online.de
• Patient organization Austria; www.zoeliakie.or.at
• Patient organization England; www.coeliac.org.uk; www.patient.co.uk/health/coeliac-Disease.htm

The success of a gluten-free diet is usually rapid and the symptoms disappear within 1-2 weeks. Even the intake of very small amounts of gluten-containing food can prevent remission and cause a relapse. A biopsy of the small intestine should be repeated after 3-6 months on a gluten-free diet. If the pathological changes in the histology persist, other causes of villous atrophy (e.g. lymphoma) must be considered. A decrease in symptoms and an improvement in small bowel morphology also leads to a decrease in anti-tissue transglutaminase antibodies (tTG) and anti-endomysial antibody titers (EMA) in serum.

Supplemental vitamins, minerals and trace elements are replaced according to the deficiencies. While mild cases often do not require treatment, severe cases require comprehensive replacement therapy. For adults, substitution includes oral iron (II) sulphate 300 mg once every 2 days to 3 times a day, oral folate 5 to 10 mg once a day, calcium supplements and all common multivitamin supplements. In individual cases, children (less frequently adults) who are seriously ill at the time of diagnosis require immobilization of the bowel and total parenteral nutrition.

If a patient responds poorly to gluten withdrawal, either the diagnosis is incorrect or the disease has become refractory to treatment. In some circumstances, corticosteroids or other immunosuppressants can improve symptoms in refractory disease.

Prognosis for coeliac disease

Complications of coeliac disease include refractory disease, collagenous sprue and the development of intestinal lymphoma. Intestinal lymphomas occur in 6-8% of patients with coeliac disease, usually manifesting 20-40 years after the onset of the disease. The incidence of other cancers of the gastrointestinal tract (carcinomas of the esophagus and oropharynx, adenocarcinomas of the small intestine) is increased: if a strict gluten-free diet is followed, the risk of cancer is significantly reduced. If people who have been on a gluten-free diet for a long time develop symptoms of coeliac disease again, it is important to get a precise diagnosis

When to seek medical help?

If coeliac disease is suspected or if gastrointestinal symptoms persist, it is important to consult a doctor. Diagnosis often requires specific blood tests and a biopsy of the small intestine.

Conclusion: Coeliac disease requires a lifelong commitment to a gluten-free diet.