Malady Wise

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Coeliac Kids

Maladywise

Overview

  • Immune-mediated damage to the small intestine in response to ingested gluten

  • Gluten is present in wheat, rye, barley, and oats

  • Affects 1 in 70 Australians, many are undiagnosed

Consequences

If untreated, Coeliac leads to an increased risk of

  • Certain lymphomas

  • Infertility

  • Premature osteoporosis

  • Developing other autoimmune diseases

Associated Conditions

  • Dermatitis herpetiformis

  • High rates of other autoimmune diseases including thyroid, liver disease and diabetes

Symptoms

  • Bloating

  • Diarrhoea or constipation

  • Large foul-smelling stools

  • Pain or nausea

  • Poor weight gain or loss

  • Prolonged fatigue or irritability

  • Severe or persistent mouth ulcers, dental enamel defects, delayed dental eruption

  • Unexplained low iron, B12 and folate

  • Short stature

  • Delayed puberty

Risk factors

  • First-degree relatives of patients with Coeliac have a 10% risk

  • Personal history of other autoimmune diseases (diabetes, thyroid, liver, Addison’s, IgA deficiency)

  • Syndromes with higher prevalence (Down Syndrome)

Testing

Blood test

  • Transglutaminase-IgA (tTG-IgA) and deamidated gliadin peptide IgG (DGP-IgG).

  • IgA levels to check concurrent IgA deficiency

  • DGP-IgG enhances pick-up by 15% compared to tTG-IgA alone, is unaffected by the 3% of patients with coeliac disease and selective IgA deficiency, and is more sensitive than tTG-IgA in children under age 3 years.

  • Consider HLADQ2 or DQ8 testing

    • Over 99% of patients with coeliac disease will be HLA DQ2 and/or DQ8 positive. Therefore, a negative test virtually excludes coeliac disease.

    • 30% to 60% of the general population will be HLA DQ2/DQ8 positive, the vast majority of which do not have coeliac disease.

  • General investigations: FBC, iron studies, vitamin B12, folate, vitamin D, LFTs, TSH.

  • Stool cultures

  • ESR/CRP

  • Faecal calprotectin

Diagnosis

tTG-IgA > 10x upper limit

  • If IgA tTG is > 10x upper limit of normal for assay, there is an option for serological diagnosis without the need for duodenal biopsies under general anaesthetic. If the family prefers serological diagnosis, send:

    • a second confirmatory blood sample for IgA anti-endomysial antibodies (IgA-EMA), or (if this is not available),

    • a repeat IgA tTG.

  • If either EMA is positive or the repeat IgA tTG is still > 10x the upper limit of normal for the assay, this is sufficient for confirmation. HLA-DQ2/DQ8 typing adds little to the confirmation in these cases.

IgA tTG elevated but < 10x upper limit

  • Request duodenal biopsies with referral and instruct the patient to remain on a gluten-containing diet.

DGP-IgG elevated

  • Request duodenal biopsies with referral and instruct the patient to remain on a gluten-containing diet.

In patients aged < 5 years who screen negative for tTG-IgA and DGP-IgG, consider repeat screening prior to adolescence.

In patients aged > 5 years who screen negative for tTG-IgA and DGP-IgG, but have high-risk factors and/or significant symptoms, consider HLA DQ2/8 gene testing.

Management

  • Life long gluten-free diet

  • Suggest that the family considers joining Coeliac Australia for information and support. There is a subscription fee of $100 to $110 to join.

  • Consider seeing a Dietitian to guide management

  • Symptoms should resolve with cessation of gluten

  • 6 monthly reviews initially with repeat blood tests to check micronutrient levels e.g. iron, vitamin B12, folate, vitamin D, and calcium.

References

Summary of Paeds talk at HMRI in 2023 by Dr Li-Zsa Tan

Pathophysiology

  • Gluten - large protein in Wheat, Barley, Rye

  • Incompletely digested into Gliadin

  • Gliadin deaminated by tTG

  • Peptides presented to CD4 T cells

  • AB produced

  • tTG is intracellular in all cells, and extracellular spaces, needed for wound healing + cellular proliferation

  • Leads to poor wound healing

  • Histology is lymphocytosis intraepithelially

  • IL15 produced

  • Disrupts epithelial barrier and tight junctions

  • Destruction of mucosa

Diagnosis

  • tTG-IgA = sens 93% spec 96%

  • EmA = sens 68 to 100, spec 77 to 100

  • Dgp IgG

Serological diagnosis

  • tTG-IgA > 10 x UL = accuracy of 99.6-100%

Endoscopy

  • Proximal duodenum with scalloping

  • Pale mucosa

  • Nodularity and patchy villous atrophy

  • Total mucosal atrophy

Symptoms

  • Puberty and growth delay

  • GI symptoms

  • Bone

  • Carditis

  • Depression

  • T cell lymphoma

  • Miscarriage

  • Cancer risk

False Positives

  • IBD

  • EoE

  • Autoimmune thyroiditis

  • Rh Arthritis

  • Ankylosing spondylitis

  • Malnutrition

Questions

  • Gluten-free oats contain Avenin not Gliadin, cross-contamination in factory, coeliac in remission show not change after trying GF oats but must be stable before attempting

  • Does GF diet prevent Coeliac? No change