On the way back from our National Meeting (NASPGHAN), I had the opportunity to read “Gluten-Related Disorders” ed. by Alessio Fasano. The book is a very good summary about the science of celiac disease (CD), wheat allergy, and nonceliac gluten sensitivity (NCGS); at the same time, there is some redundancy due to multiple authors (particularly evident in later chapters). One of the book’s features is clinical vignettes to drive home multiple teaching points. For example, the ‘refractory’ CD patient who in fact has Crohn’s disease. The book also provides a code to obtain the information online, so it is fully searchable. In the introduction, there is an in-depth explanation of why gluten can be so difficult for the GI tract. The discovery that a gluten-free diet can be helpful was a byproduct of wheat shortages during WWII. Here are some useful insights that were noteworthy:
Definitions (page 9): reviews the terms “silent CD,” “potential CD,” and “latent CD.”
- Silent =asymptomatic but with all other features: +antibodies, +HLA type, +abnl histology
- Potential =+antibodies but lack of histology evidence (antibodies often precede development of clinical disease)
- Latent =previous evidence of CD but currently tolerating gluten in diet with normal histology
- While increase in CD is partly due to awareness, there has been a “true increase in prevalence, with rates doubling every 20 years or so.”
- Early vaccinations are not risk factors for the development of CD
- Breastfeeding can reduce risk of CD by about 50% though gluten should be introduced between 4-6 months.
- Table of the main extraintestinal manifestations on page 24. Most common: anemia (especially iron deficiency), short stature, and pubertal delay.
- Associated diseases (Table 3, page 29): Down syndrome, Turner syndrome, Type I Diabetes, Williams syndrome, IgA deficiency, and Autoimmune thyroid disease.
- Eosinophilic esophagitis has been identified in a small number of patients with celiac disease. The book notes a study with 7 pediatric patients; only one of them improved their esophageal eosinophilia with a GFD.
Tips on diagnosing celiac
- Bulb abnormalities with a normal 2nd portion of duodenum biopsy can be seen in 10% or more of patients with celiac. The authors recommend obtaining 4 biopsies from 2nd and 3rd portion and 2 biopsies from bulb (separate containers) (page 144-145).
- Most celiac experts say there is no celiac without DQ2 or DQ8. There are several situations in which a negative HLA type could be helpful (page 78)
- -negative serology but abnormal histology
- -gluten-free diet (GFD) started before diagnosis confirmed
- -failure to respond to GFD
- -asymptomatic high-risk individuals to help determine if periodic serology is worthwhile
- In most individuals, obtaining TTG IgA along with serum IgA is recommended for diagnosis (and avoiding older gliadin antibody tests). If clinical suspicion is high, endoscopy is warranted regardless of result.
- Under the age of 2, deamidated anti-gliadin antibodies appear months earlier than the TTG in prospective studies, so order the dAGA IgG and dAGA IgA in kids under 2. (Available with both quest and labcorp). The deamindated anti-gliadin antibodies may be more helpful/sensitive in monitoring dietary adherence than TTG.
- Infants who have a first degree family member with celiac should be introduced to “small” amounts of gluten between 4 and 6 mos of age – not before and not delayed. It appears to promote tolerance though it’s not clear if it just delays inevitable onset. Small amounts can be a serving a day of a mixed, barley baby cereal.
- Section V is devoted to diagnosis. Table 1 (page 72) lists the sensitivity/specificity of the available serologies.
- Screening asymptomatic persons. The controversy regarding this practice is alluded to on page 75. Currently NASPGHAN recommends screening at risk groups whereas AGA does not.
- Endoscopy/Biopsy discussed (pages 78-82). States a biopsy is not needed in the case of dermatitis herpetiformis due to characteristic deposits of IgA in the dermal papilla. The authors recommend biopsy in all cases, but review ESPGHAN guidelines which state that biopsy can be omitted if TTG IgA >10 time ULN –if verified by positive EMA, HLA typing, and followed for symptomatic improvement.
- Antibody tests “become negative in 15% after 1 month on GFD and in 57% after 3 months…diagnosis of CD cannot be made while on GFD.” Algorithm for diagnosis of CD with a child on GFD presented on page 148.
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Disclaimer: These blog posts are for educational purposes only. Specific dosing of medications (along with potential adverse effects) and specific medical management interventions should be confirmed by prescribing physician. Application of the information in a particular situation remains the professional responsibility of the practitioner.