Hyperthyroidism¶

Griffin Bullock, Lauren Waskowicz

Background¶

Excess thyroid hormone caused by increased synthesis, excessive release of preformed thyroid hormone or endogenous/exogenous release of hormone from extrathyroid source
Low TSH and High T4 and/or T3 (primary): Graves’, Toxic goiter, TSH-producing adenoma, hyperemesis gravidarum, subacute granulomatous thyroiditis, amiodarone, radiation, excessive replacement, struma ovarii
Low TSH/Normal T4 and T3: Subclinical hyperthyroidism, central hypothyroidism, non-thyroidal illness, recovery from hyperthyroidism, pregnancy (physiologic)
Subclinical Hyperthyroidism: repeat testing to verify abnormality is not transient

Sx: Heat intolerance, tremor, palpitations, anxiety, weight loss (w/ normal/increased appetite), increased BM frequency, SOB
Physical Exam: Goiter, tachycardia/Afib, stare/lid lag, marked muscle weakness (rare presentation of thyrotoxic periodic paralysis), hyperreflexia
Graves Specific Findings: proptosis/exophthalmos, infiltrative dermopathy (localized or pretibial myxedema)

TSH, free T4, free T3 (only T3 or T4 may be elevated, though both often are)
- Biotin affects assay, causes falsely ↓ TSH and falsely ↑ FT4/FT3
CBC: may have a normocytic anemia due to increased plasma volume