Thyroid Disorders


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  • Thyroid Disorders

    1. 1. Thyroid Disorders Tapan A. Patel Cuong Nguyen Mona Jamaldinian
    2. 2. Thyroid Gland <ul><li>Second largest endocrine gland in body </li></ul><ul><li>Small butterfly shaped gland located at base of neck below the sternocleidomastoid muscles </li></ul><ul><li>Thyroid is controlled </li></ul><ul><li>by the hypothalmus </li></ul><ul><li>and pituitary </li></ul>
    3. 3. Functions <ul><li>Stimulates & maintains metabolic processes </li></ul><ul><ul><li>Produces thyroid hormones T3-triiodothyronine and T4-thyroxine </li></ul></ul><ul><ul><li>These hormones regulate metabolism & affect the growth and function of other systems in the body </li></ul></ul><ul><li>Secretes calcitonin to lower serum calcium levels </li></ul><ul><li>Parathyroid gland secretes PTH to raise serum calcium levels </li></ul>
    4. 4. Functions <ul><li>Metabolic stimulants of: </li></ul><ul><ul><li>Neural and skeletal development </li></ul></ul><ul><ul><li>Oxygen consumption at rest </li></ul></ul><ul><ul><li>Stimulating bone turnover by increasing formation and resorption </li></ul></ul><ul><ul><li>Promoting chronitropic and ionotropic effects </li></ul></ul><ul><ul><li>Increasing number of catecholamine receptors in heart </li></ul></ul><ul><ul><li>Increasing production of RBC </li></ul></ul><ul><ul><li>Altering the metabolism of carbs, fats, and protein </li></ul></ul>
    5. 5. Hormones: T3 & T4 <ul><li>T3 (Triiodothyronine) & T4 (Tetraiodothyronine </li></ul><ul><ul><li>Stored in Follicles (round sacs) in the thyroid filled with thyroglobulin, a thyroid protein. </li></ul></ul><ul><ul><ul><li>Dietary iodine enters follicles where they are stored as T3 and T4 </li></ul></ul></ul><ul><ul><li>T4 is converted to T3 by peripheral organs such as kidney, liver, and spleen </li></ul></ul><ul><ul><li>T3 is 10x more active than T 4 </li></ul></ul>
    6. 6. Hormones: T4 to T3 <ul><ul><li>Only 20% of total T3 is secreted by thyroid </li></ul></ul><ul><ul><ul><li>Majority is formed from catalysis of T4 by 5’-iodthryonine deiodinase (highest activity in liver and kidney) </li></ul></ul></ul>
    7. 7. Hormones: T4 <ul><li>T4-thyroxine contains 4 iodine atoms </li></ul><ul><li>It is a slow-acting pre-hormone </li></ul><ul><li>T4 takes 4 days to peak in blood </li></ul><ul><ul><li>Half-life 7 days </li></ul></ul><ul><li>Overall effects take 6 weeks </li></ul><ul><li>T3 is the active and faster-acting hormone </li></ul><ul><li>The immediate effects of T3 last 1-2 days </li></ul><ul><ul><li>Half-life 1.5 days </li></ul></ul>
    8. 8. Iodine <ul><li>Dietary Iodide is removed from the bloodstream by means of an active pump </li></ul><ul><li>The pump can concentrate iodide in the follicular sacs at 350x greater than the blood concentration </li></ul><ul><li>Oxidation of iodide by thyroid peroxidase converts iodide  iodine </li></ul><ul><li>Peripheral de-iodination of T4 to T3 is regulated by many factors including health, nutritional status, and other hormones </li></ul>
    9. 9. Hormones- TSH <ul><li>TSH </li></ul><ul><ul><li>TSH is a pituitary hormone </li></ul></ul><ul><ul><li>Controlled by TRH-thyrotropin releasing hormone from hypothalamus </li></ul></ul><ul><ul><li>Functions to stimulate thyroid hormone production </li></ul></ul><ul><ul><ul><li>May enlarge thyroid (goiter) when under producing </li></ul></ul></ul><ul><ul><li>Labs: </li></ul></ul><ul><ul><ul><li>High TSH indicates low thyroid hormone= hypo </li></ul></ul></ul><ul><ul><ul><li>Low TSH indicates high thyroid hormone = hyper </li></ul></ul></ul>
    10. 10. Hormones-Calcitonin & PTH <ul><li>Produced by thyroid to regulate serum calcium levels </li></ul><ul><li>Calcitonin stimulates movement of calcium into bone </li></ul><ul><li>Parathyroid hormone (PTH) opposite effect of calcitonin </li></ul>
    11. 11. Negative Feedback System The disruption of any of these mechanisms can cause abnormal levels of T3 and T4 leading to thyroid disease TRH T3 & T4 Thyroid TSH
    12. 12. Diseases <ul><li>Hypothyroidism-Under Activity </li></ul><ul><li>Prevalence </li></ul><ul><ul><li>Affects 5-17% of population </li></ul></ul><ul><ul><li>Females> Males </li></ul></ul><ul><ul><li>Higher in >60 years old </li></ul></ul><ul><li>Types </li></ul><ul><ul><li>Hashimoto’s thyroiditis </li></ul></ul><ul><ul><li>Ord’s thyroiditis </li></ul></ul><ul><ul><li>Postoperative hypothyroidism </li></ul></ul><ul><ul><li>Postpartum hypothyroidism </li></ul></ul><ul><ul><li>Iatrogenic hypothyroidism </li></ul></ul>
    13. 13. Diseases <ul><li>Hyperthyroidism- Over activity </li></ul><ul><li>Prevalence </li></ul><ul><ul><li>Affect 5-17% of population </li></ul></ul><ul><ul><li>Females> Males </li></ul></ul><ul><ul><li>More common in younger persons </li></ul></ul><ul><li>Types </li></ul><ul><ul><li>Thyroid storm </li></ul></ul><ul><ul><li>Graves disease </li></ul></ul><ul><ul><li>Toxic thyroid nodule </li></ul></ul><ul><ul><li>Plummers disease </li></ul></ul><ul><ul><li>Hashitoxicosis </li></ul></ul><ul><ul><li>De Quervain thryoiditis </li></ul></ul><ul><ul><li>Iatrogenic hyperthyroidism </li></ul></ul>
    14. 14. Labs 80-220ng/dL Bound & Free T 3 Total(T 3 ) 0.25-6.7U/mL Thyroid stimulating hormone TSH 22-34% Binding capacity of TBG T 3 Resin Uptake 80-220ng/dL Bound & Free T 3 Total T 3 (TT 3 ) 0.8-1.5 ng/dL Free T 4 Free T 4 (FT 4 ) 4.5-12.5mg/dL Bound & Free T 4 Total T 4 (TT 4 ) Normal Range Measurement Thyroid Function Test
    15. 15. Labs <ul><li>Hyperthyroidism </li></ul><ul><ul><li> FT4 </li></ul></ul><ul><ul><li> TSH </li></ul></ul><ul><li>Hypothyroidism </li></ul><ul><ul><li> FT4 </li></ul></ul><ul><ul><li> TSH </li></ul></ul>
    16. 16. Hyperthyroidism-Types <ul><li>Graves disease </li></ul><ul><ul><li>Most common form (70-80%) </li></ul></ul><ul><ul><ul><li>Autoimmune disorder in which thyroid-stimulating antibodies are circulating in blood. These bind to thyroid cells and activate cells in the same manner as TSH. </li></ul></ul></ul><ul><ul><li>7 times greater in women </li></ul></ul><ul><ul><li>Peak onset is 20-30’s </li></ul></ul>
    17. 17. Hyperthyroidism-Types <ul><li>Can be caused by: </li></ul><ul><ul><li>Toxic multinodular goiter </li></ul></ul><ul><ul><li>Solitary toxic nodule </li></ul></ul><ul><ul><li>Thyroiditis </li></ul></ul><ul><ul><li>Drug-induced thryotoxicosis </li></ul></ul><ul><ul><li>Pituitary or trophoblastic tumors </li></ul></ul>
    18. 18. Hyperthyroidism-Symptoms <ul><li>Weight loss </li></ul><ul><li>Tachycardia </li></ul><ul><li>Bulging eyes </li></ul><ul><li>Nervous/Anxious </li></ul><ul><li>Insomnia </li></ul><ul><li>Intolerant of heat </li></ul><ul><li>Goiter </li></ul>
    19. 19. Goiter <ul><li>A diet deficient in iodine </li></ul><ul><li>Increase in thyroid stimulating hormone (TSH) in response to a defect in normal hormone synthesis within the thyroid gland. </li></ul>
    20. 20. Thyroid Storm <ul><li>Life threatening syndrome </li></ul><ul><li>Decompensated hyperthyroidism </li></ul><ul><li>Symptoms </li></ul><ul><ul><li>Hyperthyroid symptoms with agitation, confusion, delirium, psychosis </li></ul></ul><ul><ul><li>Gastrointestinal: Nausea/Vomiting, Abdominal pain </li></ul></ul><ul><ul><li>Tachycardia associated with CHF </li></ul></ul>
    21. 21. Thyroid Storm Treatment <ul><li>Antithyroids </li></ul><ul><ul><li>PTU 200-400mg po/NG q4-8h </li></ul></ul><ul><ul><li>Methimazole 60-120mg/d PO/NG divided q6-8h </li></ul></ul><ul><li>Potassium Iodide 2-5 drops PO/NG q6h </li></ul><ul><li>Lugol Solution-Strong Iodine10 drops po TID </li></ul><ul><li>Glucorticoids: block conversion of T4 to T3 </li></ul><ul><ul><li>Hydrocortisone succinate 100-200mg IV q6-8 </li></ul></ul><ul><ul><li>Dexamethasone 2mg Po/IV q6-8h </li></ul></ul><ul><li>BB </li></ul><ul><ul><li>Esmolol: 500mcg/kg/min </li></ul></ul><ul><ul><li>Propranolol 20-80mg/dose PO/NG q4-6h </li></ul></ul>
    22. 22. Hyperthyroidism-Treatment <ul><li>Drug Therapy </li></ul><ul><ul><li>Beta blocker </li></ul></ul><ul><ul><ul><li>Atenolol 50mg-100mg po daily </li></ul></ul></ul><ul><ul><ul><li>Propranolol 20-40mg po TID </li></ul></ul></ul><ul><ul><li>Antithyroids </li></ul></ul><ul><ul><ul><li>Methimazole 15-30mg po daily </li></ul></ul></ul><ul><ul><ul><li>Propylthiouracil (PTU) 300mg TID </li></ul></ul></ul>
    23. 23. Hyperthyroid-Treatment <ul><li>Procedural Therapy </li></ul><ul><ul><li>Radionuclide albation of thyroid gland </li></ul></ul><ul><ul><li>Total thyroidectomy </li></ul></ul>
    24. 24. Methimazole <ul><li>Methimazole prevents peroxidase enzyme from coupling and iodinating the tyrosine residues on thyroglubulin. Reduces T3 & T4 production. </li></ul><ul><li>Dosage </li></ul><ul><ul><li>15-30mg PO daily </li></ul></ul>
    25. 25. Methimazole <ul><li>Adverse Effects </li></ul><ul><ul><li>Skin rash </li></ul></ul><ul><ul><li>Loss of taste </li></ul></ul><ul><ul><li>GI upset </li></ul></ul><ul><ul><li>Drowsiness </li></ul></ul><ul><ul><li>Decreased Platelets </li></ul></ul><ul><li>antagonistic properties of Methimazole </li></ul>
    26. 26. Methimazole <ul><li>Drug Interactions: </li></ul><ul><ul><li>Discontinue before treatment with radioiodine; affects uptake </li></ul></ul><ul><ul><li>Amiodarone: Increases T3 and T4 serum levels </li></ul></ul><ul><ul><li>Warfarin: enhanced due to vitamin K </li></ul></ul>
    27. 27. Propylthiouracil -PTU <ul><li>Thio-urea derivative </li></ul><ul><li>Preferred agent in pregnant women </li></ul><ul><li>DOC for severe thyrotoxicosis </li></ul><ul><li>Dosage </li></ul><ul><ul><li>Adults: 300-450mg/day divided q8h </li></ul></ul><ul><ul><li>Severe cases: 600-1200mg/day </li></ul></ul><ul><ul><li>Maintenance dose 100-150mg/day divided q 8-12 hours </li></ul></ul><ul><li>Drug Interactions </li></ul><ul><ul><li>Similar to Methimazole </li></ul></ul>
    28. 28. PTU <ul><li>Adverse reactions </li></ul><ul><ul><li>Rash </li></ul></ul><ul><ul><li>Itching </li></ul></ul><ul><ul><li>Hives </li></ul></ul><ul><ul><li>Agranulocytosis </li></ul></ul><ul><ul><li>Vasculitis </li></ul></ul>
    29. 29. Carbimazole-UK <ul><li>Pro-drug converted to active form -methimazole </li></ul><ul><li>Dosage </li></ul><ul><ul><li>15-40mg PO daily until normal function </li></ul></ul><ul><ul><li>Reduce to 5-15mg po daily maintenance dose </li></ul></ul><ul><li>Adverse Effects </li></ul><ul><ul><li>Bone marrow suppression </li></ul></ul><ul><ul><li>Neutropenia </li></ul></ul><ul><ul><li>Agranulocytosis </li></ul></ul>
    30. 30. Sodium Iodide I-131 (Iodotope) <ul><li>Quickly absorbed and taken up by thyroid </li></ul><ul><li>No other tissue capable of retaining radioactive iodine therefore low adverse effects </li></ul><ul><li>Dose </li></ul><ul><ul><li>Adult 75-150mCi/g of thyroid x estimated thyroid gland size </li></ul></ul><ul><ul><li>24hour radioiodine uptake </li></ul></ul><ul><ul><li>Discontinue antithyroid therapy 3-4days before </li></ul></ul>
    31. 31. Hypothyroidism <ul><li>Types: </li></ul><ul><ul><li>Primary hypothyroidism </li></ul></ul><ul><ul><ul><li>Most common cause </li></ul></ul></ul><ul><ul><ul><li>Failure of thyroid gland </li></ul></ul></ul><ul><ul><ul><li>Occurs primarily in women aged 30-50 years old </li></ul></ul></ul><ul><ul><ul><ul><li>Chronic autoimmune thyroiditis or Hashimotos disease is the most common primary hypothyroidism AND hypothyroidism overall </li></ul></ul></ul></ul><ul><ul><li>Secondary Hypothyroidism </li></ul></ul><ul><ul><li>Tertiary Hypothyroidism </li></ul></ul><ul><ul><li>Other causes </li></ul></ul>
    32. 32. Hypothyroidism-Symptoms <ul><li>Fatigue </li></ul><ul><li>Weight Gain </li></ul><ul><li>Depression </li></ul><ul><li>Dry skin </li></ul><ul><li>Bradycardia </li></ul><ul><li>Constipation </li></ul><ul><li>Intolerant to cold </li></ul>
    33. 33. Hashimoto’s Disease <ul><li>Autoimmune disorder in which antibodies are directed against a thyroid sites to : </li></ul><ul><ul><li>Inhibit thyroid peroxidase </li></ul></ul><ul><ul><li>Inhibit effects of TSH </li></ul></ul><ul><ul><li>Stimulate thyroid growth </li></ul></ul>
    34. 34. Hypothyroidism-Primary <ul><li>Drug induced </li></ul><ul><ul><li>Amiodarone, lithium, thiocyanates, phenylbutazone, sulfonylureas, PTU & methimazole </li></ul></ul><ul><li>Iatrogenic </li></ul><ul><ul><li>Surgical removal of the thyroid gland and radiation treatment </li></ul></ul>
    35. 35. Primary Hypothyroidism <ul><li>Thyroid gland failure </li></ul><ul><ul><li>Decrease T3 & T4 </li></ul></ul><ul><ul><li>Increase TRH due to negative feedback </li></ul></ul><ul><ul><li>Increased TSH due to decreased TRH </li></ul></ul>
    36. 36. Secondary Hypothyroid <ul><li>Pituitary failure </li></ul><ul><ul><li>Insufficient TSH release as a result of: </li></ul></ul><ul><ul><ul><li>Pituitary tumors </li></ul></ul></ul><ul><ul><ul><li>Surgery </li></ul></ul></ul><ul><ul><ul><li>Pituitary radiation </li></ul></ul></ul><ul><ul><ul><li>Pituitary necrosis </li></ul></ul></ul><ul><ul><ul><li>Autoimmune mechanisms </li></ul></ul></ul>
    37. 37. Tertiary Hypothyroidism <ul><li>Hypothalamic Failure- very rare </li></ul><ul><li>Insufficient TRH release as a result of: </li></ul><ul><ul><li>Trauma </li></ul></ul><ul><ul><li>Irradiation </li></ul></ul><ul><ul><li>Tumors </li></ul></ul>
    38. 38. Hypothyroidism-Treatment <ul><li>Drug Therapy </li></ul><ul><ul><li>Levothyroxine Sodium-DOC synthetic T4 </li></ul></ul><ul><ul><ul><li>Adults 1-1.5mgc/kg/day orally initially, adjust as needed. Average dose 1.6-1.8mcg/kg/day </li></ul></ul></ul><ul><ul><ul><li>Pediatrics 1-1.5mgc/kg/day. Average 4 mcg/kg/day </li></ul></ul></ul><ul><ul><li>Thyroid (Armour) </li></ul></ul><ul><ul><ul><li>30mg PO daily, increase 15mg q 2-3 week </li></ul></ul></ul><ul><ul><li>Liotrix (Thyrolar) synthetic combo T3 & T4 </li></ul></ul><ul><ul><ul><li>Thyrolar 1/2 (6.25/25mcg) start1 tab daily , increase PRN q 2-3 weeks. </li></ul></ul></ul><ul><ul><li>L-triiodothyronine (Cytomel) synthetic T3 </li></ul></ul><ul><ul><ul><li>25mcg PO daily/ increase 12.5-25mcg daily every 1-2 weeks </li></ul></ul></ul>
    39. 39. Hypothyroidism-Treatment <ul><li>Adverse Effects </li></ul><ul><ul><li>MI </li></ul></ul><ul><ul><li>Osteopenia </li></ul></ul><ul><ul><li>HA </li></ul></ul><ul><li>Contraindicated </li></ul><ul><ul><li>Acute MI </li></ul></ul><ul><ul><li>Treatment of obesity </li></ul></ul><ul><ul><li>Uncontrolled HTN </li></ul></ul>
    40. 40. Monitoring <ul><li>Obtain baseline FT4, TSH, LFT, CBCs before initiation of therapy </li></ul><ul><li>Repeat FT4 and TSH after 4-6 weeks on therapy and 4-6 weeks after adjustments </li></ul><ul><li>Once euthyroid state obtain thyroid function test after 3-6 months </li></ul>