Thyroid Disorders Slide Show

Slide Transcript 1. Thyroid Disorders Slide Show Tapan A. Patel Cuong; Nguyen Mona Jamaldinian 2. Thyroid Gland Second largest endocrine gland in body Small butterfly shaped gland located at base of neck below the sternocleidomastoid muscles Thyroid is controlled by the hypothalmus and pituitary 3. Functions Stimulates & maintains metabolic processes Produces thyroid hormones T3-triiodothyronine and T4-thyroxine These hormones regulate metabolism & affect the growth and function of other systems in the body Secretes calcitonin to lower serum calcium levels Parathyroid gland secretes PTH to raise serum calcium levels 4. Functions Metabolic stimulants of: Neural and skeletal development Oxygen consumption at rest Stimulating bone turnover by increasing formation and resorption Promoting chronitropic and ionotropic effects Increasing number of catecholamine receptors in heart Increasing production of RBC Altering the metabolism of carbs, fats, and protein 5. Hormones: T3 & T4 T3 (Triiodothyronine) & T4 (Tetraiodothyronine Stored in Follicles (round sacs) in the thyroid filled with thyroglobulin, a thyroid protein. Dietary iodine enters follicles where they are stored as T3 and T4 T4 is converted to T3 by peripheral organs such as kidney, liver, and spleen T3 is 10x more active than T 4 6. Hormones: T4 to T3 Only 20% of total T3 is secreted by thyroid Majority is formed from catalysis of T4 by 5’-iodthryonine deiodinase (highest activity in liver and kidney) 7. Hormones: T4-thyroxine contains 4 iodine atoms It is a slow-acting pre-hormone T4 takes 4 days to peak in blood Half-life 7 days Overall effects take 6 weeks T3 is the active and faster-acting hormone The immediate effects of T3 last 1-2 days Half-life 1.5 days 8. Iodine Dietary Iodide is removed from the bloodstream by means of an active pump The pump can concentrate iodide in the follicular sacs at 350x greater than the blood concentration Oxidation of iodide by thyroid peroxidase converts iodide  iodine Peripheral de-iodination of T4 to T3 is regulated by many factors including health, nutritional status, and other hormones 9. Hormones- TSH TSH TSH is a pituitary hormone Controlled by TRH-thyrotropin releasing hormone from hypothalamus Functions to stimulate thyroid hormone production May enlarge thyroid (goiter) when under producing Labs: High TSH indicates low thyroid hormone hypo Low TSH indicates high thyroid hormone hyper 10. Hormones-Calcitonin & PTH Produced by thyroid to regulate serum calcium levels Calcitonin stimulates movement of calcium into bone Parathyroid hormone (PTH) opposite effect of calcitonin 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. Diseases Hypothyroidism-Under Activity Prevalence Affects 5-17% of population Females> Males Higher in >60 years old Types Hashimoto’s thyroiditis Ord’s thyroiditis Postoperative hypothyroidism Postpartum hypothyroidism Iatrogenic hypothyroidism 13. Diseases Hyperthyroidism- Over activity Prevalence Affect 5-17% of population Females> Males More common in younger persons Types Thyroid storm Graves disease Toxic thyroid nodule Plummers disease Hashitoxicosis De Quervain thryoiditis Iatrogenic hyperthyroidism 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. Labs Hyperthyroidism  FT4  TSH Hypothyroidism  FT4  TSH 16. Hyperthyroidism-Types Graves disease Most common form (70-80%) 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. 7 times greater in women Peak onset is 20-30’s 17. Hyperthyroidism-Types Can be caused by: Toxic multinodular goiter Solitary toxic nodule Thyroiditis Drug-induced thryotoxicosis Pituitary or trophoblastic tumors 18. Hyperthyroidism-Symptoms Weight loss Tachycardia Bulging eyes Nervous/Anxious Insomnia Intolerant of heat Goiter 19. Goiter A diet deficient in iodine Increase in thyroid stimulating hormone (TSH) in response to a defect in normal hormone synthesis within the thyroid gland. 20. Thyroid Storm Life threatening syndrome Decompensated hyperthyroidism Symptoms Hyperthyroid symptoms with agitation, confusion, delirium, psychosis Gastrointestinal: Nausea/Vomiting, Abdominal pain Tachycardia associated with CHF 21. Thyroid Storm Treatment Antithyroids PTU 200-400mg po/NG q4-8h Methimazole 60-120mg/d PO/NG divided q6-8h Potassium Iodide 2-5 drops PO/NG q6h Lugol Solution-Strong Iodine10 drops po TID Glucorticoids: block conversion of T4 to T3 Hydrocortisone succinate 100-200mg IV q6-8 Dexamethasone 2mg Po/IV q6-8h BB Esmolol: 500mcg/kg/min Propranolol 20-80mg/dose PO/NG q4-6h 22. Hyperthyroidism-Treatment Drug Therapy Beta blocker Atenolol 50mg-100mg po daily Propranolol 20-40mg po TID Antithyroids Methimazole 15-30mg po daily Propylthiouracil (PTU) 300mg TID 23. Hyperthyroid-Treatment Procedural Therapy Radionuclide albation of thyroid gland Total thyroidectomy 24. Methimazole Methimazole prevents peroxidase enzyme from coupling and iodinating the tyrosine residues on thyroglubulin. Reduces T3 & T4 production. Dosage 15-30mg PO daily 25. Methimazole Adverse Effects Skin rash Loss of taste GI upset Drowsiness Decreased Platelets antagonistic properties of Methimazole 26. Methimazole Drug Interactions: Discontinue before treatment with radioiodine; affects uptake Amiodarone: Increases T3 and T4 serum levels Warfarin: enhanced due to vitamin K 27. Propylthiouracil -PTU Thio-urea derivative Preferred agent in pregnant women DOC for severe thyrotoxicosis Dosage Adults: 300-450mg/day divided q8h Severe cases: 600-1200mg/day Maintenance dose 100-150mg/day divided q 8-12 hours Drug Interactions Similar to Methimazole 28. PTU Adverse reactions Rash Itching Hives Agranulocytosis Vasculitis 29. Carbimazole-UK Pro-drug converted to active form -methimazole Dosage 15-40mg PO daily until normal function Reduce to 5-15mg po daily maintenance dose Adverse Effects Bone marrow suppression Neutropenia Agranulocytosis 30. Sodium Iodide I-131 (Iodotope) Quickly absorbed and taken up by thyroid No other tissue capable of retaining radioactive iodine therefore low adverse effects Dose Adult 75-150mCi/g of thyroid x estimated thyroid gland size 24hour radioiodine uptake Discontinue antithyroid therapy 3-4days before 31. Hypothyroidism Types: Primary hypothyroidism Most common cause Failure of thyroid gland Occurs primarily in women aged 30-50 years old Chronic autoimmune thyroiditis or Hashimotos disease is the most common primary hypothyroidism AND hypothyroidism overall Secondary Hypothyroidism Tertiary Hypothyroidism Other causes 32. Hypothyroidism-Symptoms Fatigue Weight Gain Depression Dry skin Bradycardia Constipation Intolerant to cold 33. Hashimoto’s Disease Autoimmune disorder in which antibodies are directed against a thyroid sites to : Inhibit thyroid peroxidase Inhibit effects of TSH Stimulate thyroid growth 34. Hypothyroidism-Primary Drug induced Amiodarone, lithium, thiocyanates, phenylbutazone, sulfonylureas, PTU & methimazole Iatrogenic Surgical removal of the thyroid gland and radiation treatment 35. Primary Hypothyroidism Thyroid gland failure Decrease T3 & T4 Increase TRH due to negative feedback Increased TSH due to decreased TRH 36. Secondary Hypothyroid Pituitary failure Insufficient TSH release as a result of: Pituitary tumors Surgery Pituitary radiation Pituitary necrosis Autoimmune mechanisms 37. Tertiary Hypothyroidism Hypothalamic Failure- very rare Insufficient TRH release as a result of: Trauma Irradiation Tumors 38. Hypothyroidism-Treatment Drug Therapy Levothyroxine Sodium-DOC synthetic T4 Adults 1-1.5mgc/kg/day orally initially, adjust as needed. Average dose 1.6-1.8mcg/kg/day Pediatrics 1-1.5mgc/kg/day. Average 4 mcg/kg/day Thyroid (Armour) 30mg PO daily, increase 15mg q 2-3 week Liotrix (Thyrolar) synthetic combo T3 & T4 Thyrolar 1/2 (6.25/25mcg) start1 tab daily , increase PRN q 2-3 weeks. L-triiodothyronine (Cytomel) synthetic T3 25mcg PO daily/ increase 12.5-25mcg daily every 1-2 weeks 39. Hypothyroidism-Treatment Adverse Effects MI Osteopenia HA Contraindicated Acute MI Treatment of obesity Uncontrolled HTN 40. Monitoring Obtain baseline FT4, TSH, LFT, CBCs before initiation of therapy Repeat FT4 and TSH after 4-6 weeks on therapy and 4-6 weeks after adjustments Once euthyroid state obtain thyroid function test after 3-6 months Source: https://www.slideshare.net/guest2c2a65/thyroid-disorders