Treatment of Hypo/Hyperthyroidism
Timothy C. Evans, MD PhD FACP Department of Medicine Univ of Washington
Thyroid Disease
• Thyroid Function Tests • Hypothyroidism • Hyperthyroidism
Thyroid Diagnostic Tests
• • • • • • Thyroid Hormone (T4, T3) Free vs. Bound (T3U, free T4) TSH Thyroid Autoantibodies Radionuclide Uptake and Scan Ultrasound
Hypothyroidism
• Clinical Presentation—fatigue, cold intolerance, dry skin/hair, heavy periods, constipation, mental slowness • Diagnosis—Elevated TSH, low free T4 • Reason to Rx—Sx, hypercholesterolemia • Treatment—Levothyroxine (LT4) • Monitoring—TSH after 6 weeks
Hypothyroidism—Etiology
• • • • Autoimmune thyroiditis Post thyroid ablation (surgery, 131I) Multinodular goiter Transient (postpartum thyroiditis, subacute thyroiditis) • Drugs—lithium, amiodarone • Congenital
Hypothyroidism Rx
• Thyroid hormone is a cardiac stimulant. • Treatment risk is precipitation of cardiac ischemia. • Go slow in fragile elderly patients, or even wait until the ischemic heart disease is stabilized before thyroid treatment. • Monitor TSH, after 6 wks equilibration.
Hypothyroidism—Case #1
• 25 y/o woman, fatigue, constipation, heavy periods, cold intolerance, neg PMHx • Thyroid gland twice normal size, firm, symmetrical • TSH—43 mU/L, free T4 0.2 • Dx? Rx?
Hypothyroidism Case #1—Answer
• Autoimmune thyroiditis (lymphocytic thyroiditis, Hashimoto’s thyroiditis) • Levothyroxine 0.1 mg qd, TSH in 6 weeks and adjust dose
Hypothyroidism—Case #2
• 65 y/o woman, fatigue, constipation, difficulty concentrating, weight loss • LDL 192 mg/dL • Thyroid twice normal size, nodular, no dominant nodule • TSH 55, free T4 0.4 • Dx? Rx? Why? How?
Hypothyroidism Case #2—Answer
• • • • • Dx probably multinodular goiter Treatment will help LDL LDL may indicate CAD Rx—levothyroxine 0.025 mg qd TSH and increase dose (?) in 6 weeks
Hypothyroidism—Case #3
• 25 y/o woman, stable hypothyroidism, LT4 0.112 mg qd, TSH 3.2, T4 9.4, T3U 1.0, FTI 9.4 • Now in second trimester pregnancy • What to expect? Why? • What to do?
Hypothyroidism Case #3—Answer
• TSH 28, T4 9.4, T3U 0.6, FTI 5.64 • Increased TBG due to increased estrogen • Increase LT4, follow TSH
Hypothyroidism—Case #4
• 25 y/o woman, stable hypothyroidism, LT4 0.112 mg qd, TSH 2.9 • Start oral contraceptives • What to expect? • What to do?
Hypothyroidism Case #4—Answer
• TSH 18 • Increase dose LT4, follow TSH
Hypothyroidism—Case #5
• 28 y/o man panhypopituitarism following pituitary surgery • LT4 0.1 mg qd, TSH 0.1, total T4 6.4 • How to treat? Follow? • If you were just starting thyroid replacement, what else would you do?
Hypothyroidism Case #5—Answer
• Increase dose LT4. • Follow free T4 and keep at high normal in order to normalize T3. • If just starting thyroid replacement, make sure cortisol coverage is started and normalized first to avoid precipitating adrenal insufficiency.
Hypothyroidism—Case #6
• 29 y/o woman, 4 months postpartum, fatigue, firm thyroid twice normal size, euthyroid before/during pregnancy • What is this? • What would you do?
Hypothyroidism Case #6—Answer
• • • • TSH 26 Dx—postpartum thyroiditis Rx—LT4, adjust dose to normalize TSH. D/C LT4 at one yr postpartum and follow TSH.
Hyperthyroidism
• Clinical Presentation—restlessness, tachycardia, heat intolerance, loose stools, eye changes, weight loss • Thyroid may be diffusely enlarged, nodular, or nonpalpable. • TSH low, T4 and T3 high • RAIU and scan to distinguish causes. • Rx because of cardiac and bone comp.
Hyperthyroidism Etiology
Graves’ disease Multinodular goiter Autonomous nodule Exogenous thyroid hormone Transient—subacute thyroiditis, postpartum thyroiditis • Drugs—amiodarone • • • • •
Hyperthyroidism Treatment Options
• Antithyroid drugs —methimazole, propylthiouracil • 131I ablation • Surgery • Propranolol • Thyroid storm—add SSKI, ipodate, glucocorticoids
Hyperthyroidism—Case #1
• 27 y/o woman, tachycardia, agitation, weight loss, heat intolerance, diffuse thyroid enlargement, thyroid bruit, exophthalmos, not pregnant • TSH < 0.03, T4 15.2, T3 358 • What is the diagnosis? • Treatment?
Hyperthyroidism Case #1—Answer
• Diagnosis—Graves’ because of exophthalmos. • Could do RAIU and scan to prove it. • Propranolol 20 mg tid, methimazole 40 mg qd
Hyperthyroidism Case #1—Part 2
• After one month treatment, TSH < 0.03, T4 10.2, T3 180 • What is the interpretation of these lab values? • Now what?
Hyperthyroidism Case #1, Part 2—Answer
• Hypothal/pit suppression • Options—medical Rx, 131I ablation • Option 1—continue methimazole for one year, adjust dose for euthyroidism. • At one year, D/C methimazole. Follow TFTs. • Treat recurrence. • Option 2—131I ablation, sooner or later.
Hyperthyroidism—Case #2
• 38 y/o woman with Graves’ disease on methimazole • Euthyroid at two months on treatment • Pt calls clinic to report multiple painful mouth ulcers. • What next?
Hyperthyroidism Case #2—Answer
• Suspect agranulocytosis. • D/C methimazole, check WBC and diff, follow. • Rx hyperthyroidism with 131I.
Hyperthyroidism—Case #3
• 62 y/o woman with sx hyperthyroidism, no exophthalmos, very large nodular gland, atrial fibrillation • TSH < 0.03, T4 14.8, T3 297 • RAIU 66%, patchy uptake • Dx? Rx?
Hyperthyroidism Case #3— Treatment
• Dx—autonomous multinodular goiter • Propranolol 20 mg tid, follow rhythm, anticoagulation. • Methimazole 20 mg qd • After euthyroid, consider cardioversion if necessary. • Rx 131I ablation.
Hyperthyroidism—Case #4
• 28 y/o woman, 25 weeks gestation, sx hyperthyroidism, TSH < 0.03, T4 15.8, T3 320, diffusely enlarged gland, exophthalmos • Dx? Dx tests? Rx?
Hyperthyroidism Case #4—Answer
• Dx—Graves’ disease • No RAIU or scan • Rx—PTU 50 mg qd, follow TFTs, treat to just barely normal. • Definitive treatment after delivery • Rx option—surgery in 2nd trimester • Watch for neonatal hyperthyroidism.
Hyperthyroidism—Case #5
• 32 y/o woman with fever, tender enlarged thyroid, elevated WBC, ESR 90, TSH <0.03, T4 13.1, T3 229, not pregnant, no exophthalmos • RAIU 0% • Dx? Rx?
Hyperthyroidism Case #5—Answer
• Dx—subacute thyroiditis • Early hyperthyroid phase followed by later more prolonged hypothyroid phase • Hyperthyroid Phase Rx—propranolol, NSAID, occasionally prednisone. • Hypothyroid Phase Rx—Levothyroxine for 6–12 months. Then usually euthyroid
Hyperthyroidism—Case #6
• 36 y/o man, malaise, fatigue, Dx hypothyroidism, Rx ―Thyroid Pills‖ • F/U still felt bad, dose increased. • F/U still felt bad, dose increased. • Presented to UWMC, still felt bad. • TSH < 0.03 • Plan—change to LT4 0.1 mg qd.
Hyperthyroidism—Case #6 continued
• • • • • • After 6 wks, TSH still < 0.03. Decreased LT4 to 0.05 mg qd. After 6 wks, TSH still < 0.03. Pt still feels bad. D/C LT4. Retest in 6 weeks.
Hyperthyroidism—Case #6 still continued
• TSH < 0.03, T4 15, T3 315 • RAIU 78%, diffuse pattern • Dx—Graves’ disease