Hyperthyroidism

Hyperthyroidism – Griffin Bullock

Background

  • Low TSH and High T4 and/or T3 (primary): Graves’ disease, 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

 

Presentation

  • Anxiety/emotional lability, weight loss, heat intolerance, tremor, palpitations, increased appetite, unexplained weight loss, new onset atrial fibrillation, myopathy, gynecomastia, menstrual disorder, rapid speech, exophthalmos, tachycardia, pretibial myxedema, tremor, hyperreflexia, lid lag, changes to hair or skin

 

Evaluation

  • 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

 

Management

  • Thyrotropin antibodies (Graves: specific test, not sensitive)
  • Radioiodine uptake scan if thyrotropin antibodies negative
  • Thyroidal blood flow evaluation on US (pregnancy)
  • Treatment: methimazole, PTU, Radioiodine ablation, surgery
    • Pts should be referred to endocrinology for treatment plan based on work up