Coeliac Disease Flashcards
Overview of Coeliac Disease
- Immune illness triggered by dietary gluten.
- 1.5 % general population prevalence. One of the most common autoimmune illnesses
- 80% of cases remain undetected.
Active case-finding - 30 at-risk individuals need to be tested to find a +’ve case of coeliac disease.
- Can develop at any age
- Median age of diagnosis 40yo.
- Slight F > M but maybe skewed due to lack of male presentation.
Associations
- Lymphoproliferative malignancies
- Sepsis
- Refractory disease
Diagnosis of Coeliac Disease
Key diagnostic features
- Intestinal histology showing raised intraepithelial lymphocytes, crypt hyperplasia and villous atrophy.
Signs of disease remission following Gluten free diet.
- Symptom resolution
- Normalised coeliac disease serology
- Mucosal healing.
Case-finding for coeliac disease
Offer serological testing to following
- Persistent unexplained abdominal or GIT symptoms
- Faltering growth
- Unexpected weight loss
- Severe or persistent mouth ulcers
- Unexplained dietary deficiency
- T1DM at diagnosis
- Autoimmune thyroid disease at diagnosis
- IBS
- 1st degree relatives +’ve
Consider serological testing in following
- Reduced BMD
- Unexplained neurological symptoms (ataxia, peripheral neuropathy)
- Subfertility, recurrent miscarriage.
- Persistently raised liver enzymes
- Dental enamel defects
- Down or Turner Syndrome.
Coeliac Serology Information
- tTG - Tissue transglutaminase
- DGP - Deamidated gliadin peptide. 95% sensitivity and 90% specificity
+‘ve serology in isolation is insufficient of diagnosis. Higher titre of serology has greater +’ve predictive value.
Persistent +’ve coeliac disease serology with normal small intestinal histology may have potential coeliac disease and follow up is recommended.
Small intestinal biopsy Information
Gastroscopy performed typically with IV sedation with total procedure taking as little as 10 minutes.
Patchy involvement of proximal small bowel. Two biopsies from 1st part of duodenum, four biopsies from 2nd part of duodenum recommended.
Sometimes can also see macroscopic changes in bowel such as mucosal scalloping, but diagnosis rests on microscopic appearance as follows:
- Intraepithelial lymphocyte proliferation.
- Crypt hyperplasia
- Villous atrophy
Note
- Villous atrophy can also be pfound in giardia, Crohn’s disease, CMPI, Olmesartan use.
HLA DQ2/8 Genotyping
Strong association with Coeliac disease.
- Almost all patients with Coeliac disease have genotypes +’ve.
- 40-50% of the Australian community regardless of presence of disease will have DQ2/8 genotypes +’ve.
- Used best to exclude disease.
Test cost to medicare is $118.85
Diagnosing gluten-sensitive or wheat-sensitive patiens
Reduced sensitivity if currently on gluten-free diet with alleviation of symptoms.
Option 1
- HLA DQ2/8 Genotyping. Absence essentially rules out.
Option 2
- Gluten challenge -> Testing.
- 3-6g gluten consumed daily for 2 weeks will cause changes in 50-70% of affected adults with development of +’ve serology about 4/52 post in 10-55%.
- 3-6g gluten = 2-4 slices of wheat bread, 2-4 weet-bix or 0.5-1 cup of cooked pasta.
Recommend to be on gluten diet for 6+ weeks.
Caution. Need to follow up with serology testing of small intestinal biopsy. Symptomatic relapse with gluten challenge is common and has poor predictive value for coeliac disease.
To improve adherence to gluten challenge, can consider specific fermented breads with lower FODMAP content to reduce potential for GIT symptoms.
Family screening
10% chance if one 1st degree family member affected - Screen all 1st degree relatives
20% chance if multiple 1st degree family members affected. Screen 1st and 2nd degree relatives.
If children are HLADQ2/8 +’ve, consider repeat coeliac serology screening every 2-3 years to avoid detrimental affects of unrecognised coeliac disease on growth and bone health.
