Approach to Thyroid Function Tests in the Evaluation of Hyperthyroidism
• Low TSH, Low normal T4 → Possibly Central Hypothyroidism. unlikely subclinical hyperthyroidism.
• Low TSH, normal T4 +/- T3 → Subclinical Hyperthyroidism: Work-up similar to hyperthyroidism as below. Can repeat labs 6 weeks after the resolution of pregnancy, critical illness, and dopamine agonists/octreotide.
• Low TSH, high T4 +/- T3 → Primary Hyperthyroidism
→ Signs of symmetrically enlarged thyroid & ophthalmopathy → Graves' Disease → Confirm with TRAb
→ Radioactive Iodine Uptake & Scan
• High or normal TSH, high T4 +/- T3 → Central (secondary) Hyperthyroidism → MRI Pituitary
- Dr. Claire Brickson @crbricks
#Hyperthyroidism #algorithm #diagnosis #endocrinology #TFTs #TSH #Interpretation
