Coeliac Disease

Coeliac Disease

Coeliac disease is a common, chronic, immune-mediated condition triggered by the ingestion of gluten, a protein found in wheat, barley, and rye. It’s an autoimmune response that leads to inflammatory damage of the small bowel lining, causing villous atrophy and malabsorption. In the UK, the National Institute for Health and Care Excellence (NICE) provides comprehensive guidance on its diagnosis and management.

 

Pathophysiology and Epidemiology

When a person with a genetic predisposition (most commonly the HLA-DQ2 or HLA-DQ8 haplotypes) ingests gluten, T-cells are activated in the small bowel. This leads to an inflammatory cascade, resulting in the destruction of the villi, which are essential for nutrient absorption.

The condition affects about 1% of the UK population, but it is more prevalent in certain groups, including those with:

  • Type 1 diabetes

  • Down’s syndrome

  • Autoimmune thyroid disease

  • First-degree relatives with coeliac disease

 

Clinical Presentation

The presentation of coeliac disease is highly varied, ranging from asymptomatic to severe malabsorption.

 

In Children

  • Gastrointestinal: Abdominal distension, chronic diarrhoea with pale, bulky, foul-smelling stools (steatorrhoea), and poor appetite.

  • Systemic: Failure to thrive and faltering growth are classic signs in young children. Older children may present with short stature.

  • Nutritional: Fatigue, lethargy, and pallor due to iron-deficiency anaemia.

 

In Adults

  • Gastrointestinal: Chronic diarrhoea, bloating, and weight loss.

  • Nutritional: Fatigue, weakness, and symptoms of nutritional deficiencies, such as oral aphthous ulcers, glossitis, and signs of anaemia.

  • Dermatological: An itchy, papulovesicular rash called dermatitis herpetiformis typically found on the elbows, knees, or scalp.

  • Other: Unexplained infertility, recurrent miscarriages, and neurological symptoms like peripheral neuropathy.

 

Diagnosis and Investigations

Crucially, patients must be consuming a gluten-containing diet for a minimum of 6 to 8 weeks before testing to ensure accurate results.

 

NICE UK Screening Recommendations

NICE recommends screening for coeliac disease in people with a range of symptoms and conditions, including:

  • Persistent, unexplained gastrointestinal symptoms (e.g., abdominal pain, bloating, diarrhoea).

  • Faltering growth, unexpected weight loss, or prolonged fatigue.

  • Unexplained iron, vitamin B12, or folate deficiency.

  • A diagnosis of type 1 diabetes or autoimmune thyroid disease.

  • First-degree relatives of people with coeliac disease.

 

Diagnostic Pathway

  1. Initial Blood Test: The primary screening test is a blood sample for tissue transglutaminase IgA (tTG-IgA) antibodies.

  2. IgA Deficiency: If a patient has a selective IgA deficiency, which is common in coeliac disease, an alternative test, such as deamidated gliadin peptide IgG (DGP-IgG) or tTG-IgG, should be used.

  3. Endoscopy and Biopsy: A small-bowel biopsy is considered the gold standard for confirmation. An endoscopy is performed, and biopsies from the duodenum show the characteristic features of villous atrophy, crypt hyperplasia, and increased intraepithelial lymphocytes. However, recent NICE guidance suggests a biopsy may be omitted in children if the tTG-IgA levels are extremely high (>10x the upper limit of normal) and a second positive blood test (EMA-IgA) is also present.

 

Management

Management of coeliac disease is a lifelong commitment and involves a strict, gluten-free diet.

  • Dietary Management: The patient must completely eliminate all foods containing wheat, barley, and rye. This requires close collaboration with a specialist dietitian to ensure nutritional adequacy and to teach the patient and their family how to read food labels and identify hidden gluten.

  • Monitoring: Regular follow-up appointments are essential to monitor symptom improvement, check for healing of the small bowel lining (with repeat serology), and to screen for nutritional deficiencies.

  • Nutritional Supplements: Vitamins and minerals, particularly iron, vitamin D, and calcium, may be needed, especially in the initial stages.

  • Patient Education: Education on the disease and its implications is vital. Referral to support groups, like Coeliac UK, is highly recommended.

  • Complications: Untreated coeliac disease can lead to long-term complications, including osteoporosis, nutrient deficiencies, and an increased but still small risk of gastrointestinal cancers, such as intestinal lymphoma.