Overview of Celiac Disease

Overview of Celiac Disease

  • Objective: Describe pathophysiology, clinical manifestations, and management of celiac disease.

Definition of Celiac Disease

  • Celiac disease is a chronic condition caused by an abnormal immune reaction to the protein gluten.

  • Gluten triggers an inflammatory response in the mucosa of the small intestine, leading to nutrient malabsorption.

  • It is classified as an autoimmune disorder, characterized by a reactive CD4+ T cell-mediated response.

Pathophysiology of Celiac Disease

Immune Mechanism

  • Involves human leukocyte antigens (HLA):

    • HLA DQ2 or HLA DQ8 on the surface of antigen-presenting cells are necessary for the development of celiac disease.

  • An autoimmune reaction occurs when T cells respond to gliadin peptides from gluten.

Gliadin and Its Role

  • Gliadin: A peptide found in wheat, rye, barley, and oats.

  • After consuming gluten, the digestive process breaks it down into gliadin.

  • Gliadin peptides permeabilize the intestinal mucosa and enter the gut wall.

Immune Response

  • Immunoglobulin A (IgA) antibodies are produced against gliadin.

  • IgA serves as a substrate for transglutaminase, leading to the formation of anti-transglutaminase antibodies.

  • This reaction causes further immune cell activation and mediators, resulting in damage to the intestinal mucosa.

Mucosal Damage

  • Villi, small finger-like projections on the mucosa of the small intestine, become:

    • Blunted or flattened, especially in the proximal small intestine (close to the duodenum).

    • Increased intraepithelial lymphocytes and hyperplasia of intestinal glands due to immune response.

  • Reduced surface area of the intestinal lining leads to decreased absorption of:

    • Carbohydrates

    • Proteins

    • Fats

  • This malabsorption results in symptoms associated with celiac disease.

Clinical Manifestations

Symptoms in Children:

  • Chronic diarrhea

  • Weight loss

  • Failure to thrive (due to malnutrition linked to diarrhea and absorption issues)

Symptoms in Adults and Children:

  • Bloating in the abdominal area

  • Iron deficiency anemia due to malabsorption

  • Constipation may occur (despite chronic diarrhea in children)

  • Fatigue

  • Abdominal pain

  • Risk of osteoporosis, particularly associated with Vitamin D malabsorption.

Diagnosis of Celiac Disease

  • Diagnostic tests include serology tests measuring:

    • Levels of Immunoglobulin A

    • Levels of transglutaminase

  • Tissue biopsy is crucial for definitive diagnosis, examining the condition of the intestinal villi and mucosa.

  • Mass classification system is used to determine the severity of celiac disease.

Management of Celiac Disease

  • Primary treatment: Adhering to a gluten-free diet, avoiding foods containing gluten to prevent inflammatory reactions.

  • Supplementation with:

    • Vitamin B12

    • Vitamin D

    • Folic acid

  • Monitoring for potential complications, especially with respect to osteoporosis in older individuals.

Summary of Pathophysiology

  • Ingestion of gluten by genetically susceptible individuals.

  • Gluten digestion leads to gliadin, which triggers an immune response.

  • Resulting chronic inflammation damages intestinal mucosa and villi.

  • Impaired absorption leads to malnutrition, diarrhea, nutrient deficiencies, and weight loss.

Concept Map Summary

  • Celiac disease involves:

    • An autoimmune reaction triggered by gluten.

    • Gliadin activates T cells, leading to interleukin 15 release.

    • Damage to enterocytes causes atrophy of villi and malabsorption syndrome.

  • Student should now have a comprehensive understanding of the pathophysiology, clinical manifestations, and management of celiac disease.

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