Thyroid Flashcards
Synthesis and Transport of Thyroid Hormones:
A. Peripheral Conversion of T4 to T3 B. Iodine organification C. Iodide conversion to iodine D. Coupling E. Proteolysis and Release
C B D E A
Converts Iodide to Iodine
Thyroid Peroxidase
Autoimmune disorder where B lymphocytes produce an antibody activating TSH receptors causing thyrotoxicosis
Graves Disease
More potent peripheral thyroid hormone
T3
Triad of Graves Disease
Exophthalmos, Pretibial Myxedema, Goiter
T3 analog
Liothyronine
T4 analog
Levothyroxine
Myxedema Coma DOC
IV Levothyroxine
Medical emergency representing end-state hypothroidism
Myxedema Coma
Dosage of Levothyroxine Loading in Myxedema Coma
300 - 400 mcg
Dosage of Levothyroxine Maintenance in Myxedema Coma
50 - 100 mcg daily
Pregnancy hyperthyroidism DOC
Propylthiouracil
Thioamides
Propylthiouracil and Methimazole
Most potent thioamide
Propylthiouracil
Side effect of thioamides
Hypothyroidism
Agranulocytosis
Teratogenic effect of Methimazole
Aplasia cutis congenita
Non-pregnant hyperthyroidism DOC
Methimazole
Propylthiouracil MOA
Inhibits thyroid peroxidase, Inhibits iodine organification and Inhibits peripheral conversion of T4 to T3
Methimazole MOA
Inhibits thyroid peroxidase and inhibits iodine organification
Acute severe neutropenia caused by thioamides
Agranulocytosis
Agranulocytosis DOC
G-CSF
Definitive treatment for hyperthyrodism
Radioactive Iodine (I 131)
Radioactive Iodine MOA
beta rays emitted destroy thyroid parenchyma
Side effect of Radioactive MOA
Permanent Hypothyroidism
Lugol’s Solution
Potassium Iodide
Iodine + Potassium Iodine
Lugol’s Solution (Potassium Iodide)
Potassium Iodide MOA
Inhibit iodine organification and release of T3 and T4
Decreased gland vascularity and size
Use of Potassium Iodide
Pre-thyroidectomy drug to reduce bleeding risk
Radiation prophylaxis
Thyroid storm
Effect of prenatal exposure to potassium iodide
Fetal goiter
Hyperthyroidism after intake of iodine
Jod-Basedow Phenomenon
Hypothyroidism after intake of iodine
Wolf-Chaikoff Phenomenon
Beta-blocker inhibiting peripheral conversion of T4 to T3
Propranolol, Atenolol, Metoprolol, Esmolol
Beta-blocker used to treat thyrotoxicosis-induced arryhthmia
Esmolol
T/F: Propranolol alters thyroid hormone levels
False
Drugs that cause peripheral conversion of T4 to T3
PTU, Propranolol, Hydrocortisone
Sudden and life-threatening acute exacerbation of thyrotoxic symptoms with granulocyte count of <500 cells/mm3
Thyroid Storm
Thyroid Storm treatment
PTU, Iodide, Propranolol, Hydrocortisone
Drug-induced hyperthyroidism
Clofibrate, Amiodarone, Methadone
Amiodarone-induced hypothyroidism DOC
Levothyroxine
Amiodarone-induced hyperthyroidism DOC
Thioamides/Hydrocortisone