I. Hashimoto's (aka lymphocytic thyroiditis, etc.)
  1. Probably autoimmune in etiology
  2. Nonfocal inflammation of thyroid with abundant lymphoid follicles and proliferation of connective tissue
  3. Long onset (years)
  4. Presents with diffusely enlarged, nontender thyroid
  5. Can cause hyperthyroidism acutely but more often just hypothyroidism from burnt-out gland
II. Subacute (granulomatous, giant cell, de-Quervain's)
  1. Multifocal inflammation surrounded by giant cells, macrophages, and granulomas
  2. Rare, usually self-limited (1-3 mos)
  3. ESR elevation is common
  4. Usually in women
  5. Suspected viral etiology
  6. Symmetrically enlarged thyroid
  7. Neck pain common
  8. Treated with glucocorticoids
III. Chronic nonspecific-most common form
  1. Caused by injury (radiation, trauma, etc.)
  2. Lots of lymphocytes and plasma cells