OVERVIEW oF CELIAC DISEASE
- Definition: Celiac disease (gluten-sensitive enteropathy, nontropical sprue) is a small bowel disorder characterized by:
- Mucosal inflammation
- Villous atrophy
- Crypt hyperplasia
- Cause: An immune-mediated disorder triggered by gliadin (component of gluten found in wheat, barley, and rye).
- Prevalence: ~1 in 300 individuals (rarer in those of Chinese, Japanese, or African descent).
PATHOPHYSIOLOGY
- Genetically determined immune process.
- Gluten exposure → tissue transglutaminase (tTG) deamidates gliadin → enhanced immunogenicity → autoimmune reaction.
- Key antibodies:
- IgA anti-endomysium
- IgA anti–tissue transglutaminase
- Mechanism: Ongoing immune response damages the small intestinal villi → malabsorption.
CLINICAL PRESENTATION
- Common malabsorption signs:
- Steatorrhea (foul-smelling, floating stools)
- Diarrhea
- Weight loss
- Abdominal pain/distension
- Nutrient deficiencies:
- Iron deficiency anemia (microcytic)
- B vitamin deficiencies (e.g., vitamin B12)
- Vitamin D and calcium deficiency → osteopenia, osteoporosis, osteomalacia
- Vitamin K deficiency → easy bruising, coagulopathy
- Other manifestations:
- Growth failure in children
- Dental enamel defects
- Edema (protein loss)
ASSOCIATED CONDITIONS
- Dermatitis herpetiformis (itchy papulovesicular rash)
- Type 1 diabetes (5% of T1D patients have celiac disease)
- Autoimmune thyroid disease
- IgA deficiency
- Liver disease
- Down syndrome (up to 16% may have celiac disease)
DIAGNOSTIC EVALUATION
- Clinical suspicion:
- Chronic diarrhea, malabsorption, weight loss
- Iron/B12 deficiency
- Osteopenia/osteoporosis
- Infertility, short stature, delayed puberty
- Initial tests:
- Serology (on a gluten-containing diet):
- IgA tissue transglutaminase antibody (tTG-IgA)
- IgA endomysial antibody (EMA)
- If IgA is deficient → use IgG-based tests (tTG-IgG).
- Serology (on a gluten-containing diet):
- Small bowel biopsy (gold standard for confirmation):
- Villous atrophy
- Crypt hyperplasia
- Increased intraepithelial lymphocytes
- 72-hour stool fat (to document steatorrhea) is sometimes used to characterize malabsorption severity.
MANAGEMENT
- Gluten-free diet (lifelong):
- Eliminate wheat, rye, barley
- Dietitian consultation
- Focus on strict label reading for hidden gluten
- Supplementation:
- Correct nutrient/vitamin deficiencies (e.g., iron, vitamin B12, vitamin D, calcium, vitamin K)
- Response:
- Symptom improvement usually within ~2 weeks
- Nonresponse often linked to inadvertent dietary gluten