Definition
- Autoimmune destruction of the thyroid gland
- Characterized clinically by gradual thyroid failure, with or without goiter formation
- The major cause of Hypothyroidism in adults
- Enlarged painless thyroiditis
Risk factors
- Genetics
- Autoimmune conditions
- Iodine excess
- Radiation
- Female (4-10:1)
Pathophysiology
- Autoimmune-mediated destruction of thyrocytes
- Formation of immune complexes and compliment in basement membrane of follicular cells
- Thyroid function altered
- Impaired T3 and T4 production due to TPO inhibition
- Infiltration of lymphocytes and resultant fibrosis
- “Chronic lymphocytic thyroiditis”
- Decreased number and efficiency of thyroid follicles
- Autoantibodies
- Presence of Thyroid Peroxidase antibodies (anti –TPO Abs) can be detected
- Many also have antibodies that block TSH
Management
- Thyroid hormone replacement