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hyperthyroid

Thyroid Disorders: Hyperthyroid

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  • Graves Disorder, pituitary adenomas, toxic goiter, drug-induced (excess thyroid hormone, amiodarone)
    elevated free T4, suppressed TSH
  • Can use radioactive iodine update study to diagnose. Uptake is elevated if thyroid is excessively secreting T4 or T3: Graves disease, TSH-secreting adenoma, toxic adenoma, multinodular goiter
  • Clinical presentation: weight loss, lid lag, heat intolerance, goiter, fine hair, tachycardia, nervousness, menstrual disturbances, sweating, exophthalmos
  • Normal TSH: 0.4-4 (clinically significant if less than <2.5).

Treatment:

  • Ablation is the treatment of choice
  • Can use meds in patients waiting for ablation or those who are not surgical candidates
    • propylthiouracil 100 mg TID, max 400 mg TID, may reduce to 50 mg when euthyroid.
      • PTU may cause hepatotoxicity. Routine liver tests suggested.
    • methimazole – preferred unless pregnant, 10-20 mg daily up to 40 mg TID, may reduce to 5-10 mg daily once euthyroid
    • Both drugs can cause a rash, arthralgias, fever, agranulocytosis early in therapy
    • Max effect can take 4-6 months. Remission only 20-30%.  Usually, need 12-18 month trial. Monitor every 1-3 months
  • Can use non-selective Beta-blockers (primarily propranolol, may use nadolol). Use mostly for symptom relief or acutely during Thyroid storm.
  • Iodines: Lugol solution has a limited efficacy of 7-14 days.

Thyroid Storm:

  • AVOID NSAIDS IN THYROID STORM
  • Life-threatening: caused by trauma, infection, antithyroid agent, withdrawal, severe thyroiditis, post-ablative therapy

Treatment:

  • Ablation is the treatment of choice
  • propylthiouracil – 500-1000 mg, then 250 mg every 4 hours
  • methimazole – 60-80 mg daily
  • Iodine therapy 1 hour after PTU
  • Beta-blocker therapy: propranolol or esmolol for symptoms
  • APAP for fever. No NSAIDS.  They displace protein-bound thyroid hormone
  • Prednisone 300 mg IV, then 100 mg every 8 hours.

You can use PTU in the first trimester of pregnancy (causes hepatotoxicity) and methimazole at the start of 2nd trimester (can cause embryopathy in first)