II. Pathophysiology

  1. Autoimmune lymphocytic infiltration of Thyroid
  2. Results in Thyroid follicle destruction with release of preformed Thyroid Hormone

III. Epidemiology

  1. More common in women by 4 fold

IV. Signs

  1. Painless Goiter (50%)
  2. Hyperthyroidism (up tp 20%)
    1. Duration: Typically <4 months
    2. Followed by Hypothyroidism and then euthyroid

V. Differential Diagnosis

VI. Labs

  1. Thyroid Function Tests (T4 Free and TSH)
    1. Vary based on phase of illness
  2. Antibodies
    1. Antithyroid Peroxidase Antibody or TPO Antibody (positive in 50%)
    2. Thyroid Stimulating Immunoglobulins absent
      1. Contrast with Grave's Disease

VII. Imaging

  1. Radioiodine Uptake (Thyroid uptake and scan)
    1. Low uptake in hyperthyroid phase (contrast with Grave's Disease)

VIII. Management

  1. Beta Blockers (e.g. Propranolol)
    1. Indicated for Hyperthyroidism symptoms
  2. Levothyroxine
    1. Indicated for symptomatic Hypothyroidism or persistent, chronic Hypothyroidism

IX. Course

  1. Resolves within 12 months (up to 18 months) in 89% of cases
  2. Hypothyroidism persists chronically in 10-20% of cases
  3. Recurrence in 5-10% of cases

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