II. Pathophysiology
- Autoimmune lymphocytic infiltration of Thyroid
- Results in Thyroid follicle destruction with release of preformed Thyroid Hormone
III. Epidemiology
- More common in women by 4 fold
IV. Signs
- Painless Goiter (50%)
-
Hyperthyroidism (up tp 20%)
- Duration: Typically <4 months
- Followed by Hypothyroidism and then euthyroid
V. Differential Diagnosis
- Drug-Induced Thyroiditis
-
Postpartum Thyroiditis
- Nearly identical, except limited to Postpartum Period
-
Hashimoto's Thyroiditis
- Similar, except pathology (Fibrosis, Hurthle Cells)
-
Grave's Disease
- Presents with pretibial edema, Proptosis
- Subacute Thyroiditis
VI. Labs
-
Thyroid Function Tests (T4 Free and TSH)
- Vary based on phase of illness
- Antibodies
- Antithyroid Peroxidase Antibody or TPO Antibody (positive in 50%)
- Thyroid Stimulating Immunoglobulins absent
- Contrast with Grave's Disease
VII. Imaging
-
Radioiodine Uptake (Thyroid uptake and scan)
- Low uptake in hyperthyroid phase (contrast with Grave's Disease)
VIII. Management
-
Beta Blockers (e.g. Propranolol)
- Indicated for Hyperthyroidism symptoms
-
Levothyroxine
- Indicated for symptomatic Hypothyroidism or persistent, chronic Hypothyroidism
IX. Course
- Resolves within 12 months (up to 18 months) in 89% of cases
- Hypothyroidism persists chronically in 10-20% of cases
- Recurrence in 5-10% of cases