Hyperthyroidism Diagnosis and Management
Initial Diagnostic Workup
- For patients with suspected hyperthyroidism, measure TSH, free T4, and free T3 to confirm the diagnosis, then obtain radioactive iodine uptake and scan to distinguish between Graves' disease, toxic multinodular goiter, and toxic adenoma 1
- TSH <0.1 mIU/L with elevated free T4 and/or T3 confirms overt hyperthyroidism 1
- Radioactive iodine uptake distinguishes destructive thyroiditis (low uptake) from true hyperthyroidism (elevated uptake) 1
- Beta-adrenergic blockers should be used for symptomatic relief in all patients with thyrotoxicosis regardless of etiology, particularly important in elderly patients and those with cardiac disease 1
Critical Monitoring for Adverse Effects
- Agranulocytosis is the most serious adverse effect of antithyroid drugs, occurring more frequently with higher doses 1
- Instruct patients to discontinue medication immediately and seek medical attention for fever, sore throat, or mouth sores 1
Special Populations
- Repeat thyroid function testing within 2 weeks if TSH <0.1 mIU/L in patients with cardiac disease or atrial fibrillation 1
- More aggressive initial treatment warranted due to cardiovascular risks in patients with cardiac disease or atrial fibrillation 1
- Avoid iodine exposure (radiographic contrast) as it may precipitate overt hyperthyroidism in patients with nodular thyroid disease 1
- Requires special consideration and closer monitoring in patients with nodular thyroid disease 1
Treatment Monitoring and Titration
- Once euthyroid, reduce methimazole dose by 50% and monitor every 6-8 weeks 2