- 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
- propylthiouracil 100 mg TID, max 400 mg TID, may reduce to 50 mg when euthyroid.
- 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)