Maybe It’s My Thyroid…..

1. Maybe It’s My Thyroid….. Cindy Brown, RN, MN, ANP, CDE Southeastern Endocrine & Diabetes

2. Introduction • One in ten Americans have a thyroid disorder • May be thought of as “common cold” of emotional illness • Women in particular emotionally affected by thyroid imbalance

3. Introduction…. • Bodily functions influenced by the thyroid at the heart of a woman’s being: • Weight • Fertility • Pregnancy • Menopause • Osteoporosis

4. Introduction • Body’s response to thyroid disorders - fatigue - most common reason to seek healthcare.

5. Thyroid Hormone Action • Activates nuclear receptors which regulate expression of thyroid hormone-responsive genes: • Fetus & neonate: differentiation of target tissues • Childhood: differentiation/proliferation • Adolescent: role in action of sex steroids

6. Thyroid Hormone Action • Gene expression: • All ages: • Regulates energy production • Regulates functional /structural proteins • Regulates action of other hormones - glucocorticoids, mineralocorticoids, growth factors, biologic amines (catecholamines)

7. Negative Feedback Loop • Thyroid hormone inhibits pituitary secretion of TSH • TSH very sensitive indication index of action • TSH & thyroid hormones maintained in a certain relationship • Modified by TBG (thyroxine-binding globulin)

8. Negative Feedback Loop • High TBG = elevated serum levels thyroid hormone • Low TBG = low serum thyroid • Serum concentrations of TBG influences negative feedback regulation of TSH

9. Negative Feedback Loop • Elevated serum thyroid levels = decreased levels TSH = Hyperthyroidism • Decreased serum thyroid levels = increased TSH = Hypothyroidism

10. Serum Levels of Thyroid Hormones • T3regulates peripheral action of hormone • T3& T4 both released from gland • Peripheral conversion of T4 to T3occurs in liver and target tissues • In presence of liver damage, T3 conversion may be low despite good levels of T4

11. TBG Metabolism • T4 transported to tissue by TBG • High serum TBG (liver damage, pregnancy, OCP’s, HRT) lowers serum concentrations of free T4 which decreases amount of substrate (T4) that can be converted to T3 • Indirect measure of TBG abnormality is T3 uptake

12. Causes of Thyroid Disorders • Hyperthyroidism • Graves’ disease: autoimmune; TSH receptor antibodies • Thyroiditis: • Sub-acute • Post-partum • Pituitary tumor - TSH producing

13. Causes of Thyroid Disorders • Hypothyroidism • Hashimoto’s: autoimmune; TPO and thyroglobulin antibodies • RAI: radioactive iodine ablation • Surgery • Antithyroid drugs • Goitrogens: lithium, amiodarone

14. Differentials • Hashimoto’s autoimmune thyroiditis • Most common cause • Iodine deficiency • Thyroiditis • Pituitary tumors • Treated hyperthyroid –Iatrogenic • CFS • FMS • Flu • Dysmenorrhea/Menorrhagia • Anemia

15. Normal Thyroid Hormone Levels • TSH: 0.4-5.5 MIU/L • Total T3: 60-181 NG/DL • Total T4: 4.5-12.5 MCG/DL • T3 Uptake: 22-35%

16. Hypothyroidism • High TSH, low T3, T4 • Symptoms: • Fatigue • Weight gain • Hypersomnia • Cold feeling • Dry hair, nails, skin • Hair loss • Muscle weakness • Memory deficits

17. Hypothyroidism • Symptoms: • Constipation • Peripheral edema • Periorbital edema • Bradycardia • Hypotension • Heavier or longer menses • Infertility • Inability to exercise

18. Hypothyroidism • Treatment: • Thyroid hormone replacement (L-T4) • Absorbed from small intestine • 6-day half-life • Once daily dosing • Minimal day-to-day variation • Branded preparations preferred to generic

19. Hypothyroidism • Treatment • Available brands: • Synthroid • Levoxyl • Levothroid • Unithroid • Doses: • 0.025-.300 mgs

20. Hypothyroidism • Treatment • Initial dose: • 1.7 mcg per kg • Pregnant: may need 1.8 mcg per kg • Elderly: usually start at lower doses, esp. with angina or CAD

21. Monitoring Hormone Levels • Initially, every 6-8 weeks • When TSH has been stable x 3-6 months, only annual monitoring necessary unless symptomatic • Pregnancy: every trimester; more often if changing doses

22. Hypothyroidism • Myxedema Coma: • End stage of uncompensated hypothyroidism • Presents most often in elderly and women in winter months • Present in respiratory failure, hypotension, bradyarrythmia, along with serious precipitating illness • Treatment is T4 IV @ 1/10th dose of oral

23. Hypothyroidism • Myxedema Coma: • Treatment : • Must be in ICU with support for failing body systems

24. Hypothyroidism • Pearls: • Most feel best with TSH between 1-2 • If TSH normal, but pt. Still not feeling good, think low T3; may need Cytomel (oral T3) • Depression very common • Inadequately treated hypothyroidism can contribute to infertility

25. Hyperthyroidism • Low TSH, High T3 and T4 • Symptoms: • Tachycardia • Atrial fibrillation • Fine tremor • Weight loss • Sweating

26. Hyperthyroidism • Symptoms: • Fatigue • Heat intolerance • Intestinal hyperactivity • Irritability • Decreased or absent menses • Bulging eyes (stare)

27. Hyperthyroidism • Treatment: • Antithyroid drugs (ATD’s) • Radioactive Iodine Ablation (RAI) • Surgery

28. Hyperthyroidism • Antithyroid drugs: • Propylthioluricil (PTU) • Methmizole (Tapazole) • Both inhibit thyroid hormone synthesis in the thyroid gland • PTU inhibits peripheral conversion of T4 to T3

29. Hyperthyroidism • Dosing: • Tapazole: 10 mg BID or TID • PTU: only 50 mg tablets available • Usual starting dose: 2 tabs TID; may double dose if necessary • Both very effective at lowering thyroid hormone levels • TSH will stay suppressed several months

30. Hyperthyroidism • Dosing: • Monitor every 4-6 weeks • When TSH rises, may need to add T4 (thyroid hormone) • Want to leave on ATD’s long enough to allow TSH receptor antibodies to decrease & induce remission; usually 12-18 months

31. Hyperthyroidism • ATD’s: • Side effects: • Leucocytopenia • Agranulocytosis-most serious • Pernicious anemia • Thrombocytopenia • Hepatic dysfunction • Allergy (discoid rashes)

32. Hyperthyroidism • Radioactive Iodine Ablation • Administration of I131 tagged iodine by mouth • Used after TFT’s normal or if unable to control hyperthyroidism with drugs • Usually destroys gland over 3-6 months • Induces permanent hypothyroidism • May cause post-treatment thyroid storm (rare)

33. Hyperthyroidism • Radioactive Iodine Ablation: • Can cause aggravation of Graves’ eye disease • No pregnancy within 6 months of treatment • Surgery: • When disease state or gland size can’t be controlled with drugs • When gland causing obstructive signs

34. Hyperthyroidism • Thyroid Storm • Occurs most often with Graves’ disease • Hormone levels same as with Graves’ • Cardinal signs: • Temperature 102 to 1050 • Profuse sweating • Marked tachycardia (120-140 pulse rate or higher) • Atrial fibrillation

35. Hyperthyroidism • Thyroid storm: • Signs: • CHF • Confusion • Severe restlessness • Coma • Usually induced by concurrent infection or surgery on hyperactive gland

36. Hyperthyroidism • Thyroid storm: • Treatment: • PTU orally or by NG tube • Tapazole not favored because it does not inhibit peripheral conversion of T4 to T3 • Beta blockade, PO or IV • Supportive therapy for fever, dehydration • Perhaps iodine solution or corticosteroids

37. Hyperthyroidism • Graves’ Eye Disease: • Caused by antibody effect on orbital tissue • Includes: • Edema • Inflammation • Hypertrophy of extraocular muscles & orbital fat • Leads to exophthhalmos (proptosis or bulging), upper & lower lid retraction, strabismus, herniated orbital fat

38. Hyperthyroidism • Graves’ Eye Disease: • Should be stabilized for 6 months prior to any other treatment modality • Exception is optic neuropathy caused by strangulation of optic nerve • Extent of protrusion measured by increase in distance between lateral orbital rim and anterior aspect of eye

39. Thyroid Nodules • May be a single nodule or larger of multiple nodules • 95% benign • More common in women, more likely malignant in men • Increase in size while on T4 therapy worrisome for malignancy

40. Thyroid Nodules • Note size, consistency and mobility on physical exam • Usually TSH suppressed, T3 and T4 levels normal • Antibodies may be present, but more likely not • Ultrasound best way to diagnose

41. Thyroid Nodules • Treatment: • Multinodular gland without dominant nodule: T4 to shrink if TSH not suppressed • Single nodule =/> 1 cm: fine needle aspiration • Enlarging nodule despite “good” dose of T4, indeterminate or malignant result from FNA: surgery

42. Thyroiditis • Most common cause: chronic autoimmune thyroiditis or post-partum thyroiditis • Next is subacute thyroiditis • More rare: acute supporative thyroiditis

43. Thyroiditis • Post-partum thyroiditis: • May occur anytime in the first year, but most common in first 3 months • Usually have hyperthyroid symptoms first, followed by hypothyroid findings • Gland usually enlarged • Will not have other markers for inflammation: fever, tenderness, high sed rate

44. Thyroiditis • Post-partum: • Usually spontaneously resolve • May need temporary medication support for symptoms • Beta blockers for tachycardia • Tranquilizers for anxiety • T4 for hypothyroidism • Can progress to permanent hypothyroidism

45. Thyroiditis • Subacute: • Usually follows viral illness • Gland is swollen, tender • Sed rate elevated >50mm/hour • May have fever • Leucocytosis • Follows usual pattern of transient hyperthyroidism, then hypothyroidism, then euthyroid

46. Thyroiditis • Subacute: • Treatment: • Symptomatic • NSAIDS for pain, fever • Prednisone for severe pain unrelieved by above • Beta blockers for hyper phase • Thyroid replacement for hypo phase • Resolve spontaneously • Usually no long term hypothyroidism

47. Maybe It’s My Thyroid…. • Questions ?

48. Maybe It’s My Thyroid... • Thank you for your kind attention!