Approach to the Diagnosis of Hyperthyroidism - Differential Diagnosis and Workup Algorithm • Secondary Hyperthyroidism (↑↔TSH, ↑Total T3/Free T4) • Subclinical Hyperthyroidism (↓TSH, ↔Total T3/Free T4) • Overt Hyperthyroidism (↓TSH, ↑Total T3/Free T4) • ß-hCG-associated Hyperthyroidism (↑↑↑ ß-hCG) • Hyperthyroidism unlikely (↔TSH, ↔Total T3/Free T4) Radioactive Iodine Scan - High Uptake: • Graves disease • Low iodine state, Gestational trophoblastic disease • Toxic adenoma, Multinodular goiter Radioactive Iodine Scan - Low Uptake: • Early Hashimoto thyroiditis (i.e., hashitoxicosis) • Thyroiditis, Iodine (e.g. contrast), Struma ovarii, Amiodarone • Exogenous thyroid hormone use Matthew Ho, MD PhD @MatthewHoMD #Hyperthyroidism #Differential #Diagnosis #Algorithm #endocrinology
