Celiac Disease Overview

Introduction

• Celiac disease: inflammatory disease triggered by ingestion of gluten (protein gliadin) in susceptible individuals.
• Can present with or without symptoms:
  • Common symptoms: abdominal pain, discomfort, bloating, diarrhea, stinky stool (steatorrhea), anemia, weight loss, and failure to thrive in children.
  • Asymptomatic in one-third of cases.

Clinical Signs

• Diarrhea, weight loss, and anemia (iron deficiency or vitamin B12).
• Facial signs: aphthous ulcers, atrophic glossitis (from anemia), and anorexia (from malabsorption).
• Dermatitis herpetiformis (Düring's disease): chronic, itchy blistering skin condition on extensor surfaces (elbows, ankles, below knees).

Diagnosis

1. Investigations

   • Full blood count: detect anemia or infections.
   • Electrolyte urea creatinine: check for malabsorption or electrolyte imbalance.
   • Liver function tests (LFTs): rule out liver or biliary tree issues.
   • Blood smear: identify type of anemia.
   • Serology tests: detect autoantibodies (transglutaminase, endomycin, gliadin).
   • Endoscopy: gold standard; involves biopsy of small intestine tissue before and after gluten consumption.

2. Tissue Changes in Celiac Disease

   • Increase in lymphocytes, crypt hypertrophy, and villus atrophy (hallmarks of diagnosis).

Management

• Diet: Gluten-free diet (avoid barley, rye, oats, wheat - BROW acronym).
• Supplements: For malabsorption (calcium, iron, vitamins).
• Celiac Crisis: Life-threatening condition needing urgent treatment:
  • Symptoms: unexplained diarrhea, severe malabsorption, massive electrolyte imbalance.
  • Treatment: rehydration with electrolytes, corticosteroids for inflammation and pain.

Pathophysiology

• Small Intestine Structure:

  • Jejunum, duodenum, stomach, enterocytes, mucus, lamina propria.
  • Antibodies (IgA) on mucus, antigen-presenting cells in lamina propria.
  • Risk factors: family history, autoimmune thyroid disease, type 1 diabetes, IgA deficiency, inflammatory bowel disease.

• Disease Mechanism:

  • Gliadin from gluten absorbed, converted to deaminated gliadin peptides by tissue glutaminase.
  • Antigen-presenting cells present peptides to naive T-cells via HLA-DQ2/DQ8:
    • T-cells become CD8 (T killer) or CD4 (T helper) cells.
  • T killer cells promote inflammation; T helper cells activate B cells, leading to antibody production (anti-gliadin, anti-endomycin, anti-transglutaminase).
  • Inflammation damages small intestine, affecting nutrient absorption.

Pathological Changes

• Villous atrophy, crypt hyperplasia, increased lymphocytes, cell death.

Complications

• Anemia, increased risk of tumors (GIT T-cell lymphomas), hyposplenism, osteoporosis, neuropathies.

Differential Diagnoses

• Cow milk sensitivity, food-sensitive enteropathies, Crohn's disease, colitis, GIT lymphoma, Whipple's disease, Giardia lamblia infection, Irritable bowel syndrome.