DIAGNOSING COELIAC DISEASE

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*NOTE: Please ensure parents/patient does not change the diet prior to consultation

NOTE: If GP has patient with positive TTG they can refer to Paediatric Gastroenterologist

PLEASE SEE ENCLOSED GUIDELINE

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Dr Charlie Charlton

Dr Mary Weston

June 06

Coeliac Disease

Background

  • Coeliac Disease is an autoimmune disorder
  • Can present with a wide range of symptoms
  • Silent and atypical forms are increasingly being recognised.
  • Some individuals are at increased risk because of heredity or associated disorders.
  • There should be a low threshold for doing the indicative tests as the number diagnosed in Nottingham and Trent is lower than expected ( estimated prevalence 1:100 in the UK)

Coeliac disease is diagnosed by having

  • a positive history
  • positive serology (suggesting a high chance of having coeliac disease)
  • positive histology findings on an adequate gluten containing diet (may need a dietetic assessment)
  • response to a gluten-free diet

If the child has significant GI symptoms without positive serology the child may still need a biopsy to look for other GI pathology.

If the child has mild symptoms and negative serology the child could be monitored and repeat serology at a later stage particularly if symptoms increase.

If patient has positive serology and normal histology (check adequate biopsy speciman) a repeat endoscopy should be done if clinical picture changes e.g faltering growth, increase or change in GI symptoms, poor diabetic control, develops anemia etc

Serology

Anti-Gliadin antibody tests ( IgA and IgG) have been superceded by use of other tests.IgG gliadin antibodies can occur in 30% of control populations and have repeatedly been shown to be extremely non-specific.

Endomysial Antibodies (EMA) have a higher specificity

Tissue transglutaminase (tTG) has been identified as the major autoantigen in coeliac disease.

In terms of sensitivity and specificity antiendomysial antibodies (EMA) and tTG titres are the preferred serological screening tests.

  • EMA (immunofluorescent test) have a specificity close to 99% but sensitivity of 90-92%.
  • IgA-tTG screening tests(ELISA test) have been developed with sensitivities and specificities in the 93-97% range.
  • In IgA deficiency IgG-EMA and IgG-tTG should be measured. TTG antibodies can be falsely positive in patients who have other bowel disorders and especially in patients who have other autoimmune conditions like Type 1 Diabetes.

Gluten causes intestinal damage in individuals whose antigen-presenting cells express either the heterodimer DQ2 (produced by individuals who are HLADR3 (or DR5/DR7)) or the heterodimer DQ8 (produced by those who are HLADR4) – therefore genetic markers are another useful test.

NB: Confirmation of the diagnosis requires a biopsy on an adequate gluten containing diet in all cases.

Using the BSGHAN Coeliac Disease Working Party Guideline we have developed the following algorithm for Nottingham (see overleaf)