1. Chapter 34 Agents Affecting Thyroid, Parathyroid, and Pituitary Function

2. 2 Goal: maintenance of physiologic stability Hypothalamus and the pituitary gland  Form the neuroendocrine system  Main director is the hypothalamus

3. 3 Pituitary Gland  Adenohypophysis (anterior pituitary)  Neurohypophysis (posterior pituitary) Linked to the hypothalamus Pituitary gland secretes hormones Coordinates action of other endocrine glands Influences growth and development of the body

4. 4 Pituitary Disorders Hypopituitarism  Underproduction of pituitary hormones Therapy  Corticosteroids: a life and death issue  Thyroid replacement  Sex hormone replacement

5. 5 Pituitary Disorders Hyperpituitarism  Overproduction of pituitary hormones  Signs and symptoms: gigantism and acromegaly Treatment  Chemotherapy  Radiation  Surgery—inactivation or removal

6. 6 Pituitary Disorders Diabetes insipidus  Caused by a deficiency or total absence of vasopressin (ADH)  Signs and symptoms Huge urine output (polyuria) Increased thirst (polydipsia) Hypernatremia (increased sodium) Dehydration  Treatment: antidiuretic hormone

7. 7 Antidiuretic Hormone (ADH) Directs the body to retain water and sodium  Focus is on water versus sodium Causes vasoconstriction Synthetic ADH drugs  Lypressin  Vasopressin

8. 8 Nursing Considerations Monitor: weight, I&O, vasopressin toxicity, B/P daily Vasopressin: regular schedule Teach: may produce chest pain; administration techniques Watch the elderly and patients with CAD carefully

9. 9 Thyroid Gland Thyroid gland location: neck  Produces T 3 and T 4 hormones Cellular metabolism  Produces calcitonin Inhibits bone resorption

10. 10 Thyroid Maintains metabolic rate Two thyroid hormones Synthesis is a series of chemical steps Synthesis is dependent on thyroid stimulating hormone (TSH) Negative feedback system Thyroid hormone increases – TSH is suppressed

11. 11 Thyroid Hormones Regulate lipid and carbohydrate metabolism Essential for normal growth and development Affect heat production in the body

12. Thyroid Hormones (cont’d) Promotes metabolic breakdown of cholesterol to bile acids Accelerates utilization of carbohydrates Dysfunction has serious consequences 12

13. 13 Thyroid Disorders: Hyperthyroidism Excessive secretion of thyroid hormones  Increased metabolism

14. 14 Hyperthyroidism: S/S  Skin hot and dry  Increased cardiac and respiratory rates  Weight loss  Increased appetite  Muscle weakness  Nervousness  Irritability  Unable to sleep well

15. 15 Antithyroid Drugs Inhibits coupling of iodine  Prevent T 3 and T 4 formation Iodides  Stop thyrotropin from being active Inhibits the production of T 3 and T 4 Radioactive isotopes  Diagnose and treat hyperthyroidism Radiation destroys the thyroid gland

16. 16 Antithyroid Drugs Methimazole and propylthiouracil (PTU) Side effects/adverse effects  Liver and bone marrow toxicity Interactions  Increased activity of oral anticoagulants  Additive agranulocytosis when taken with bone marrow depressants Therapeutic results  Normal metabolic rate

17. 17 Iodides Treats mild cases of hyperthyroidism Inhibits production of thyroid hormones May have effect in 24 hours Maximum effect with 10-15 days Thyroid gland may “escape” from iodine inhibition

18. 18 Sodium Iodide I 131 Radioactive isotopes of iodine Used for diagnosis and treatment of hyperthyroidism Oral or IV Taken up by the thyroid gland Destructive radiation destroys thyroid cells Careful dose selection limits amount of damage

19. 19 Beta-Adrenergic Blocking Agents Suppresses signs and symptoms of hyperthyroidism - tachycardia - tremor - anxiety Do not inhibit function of the thyroid gland An adjunct to other forms of therapy

20. 20 Surgery Subtotal thyroidectomy Used when other forms of therapy are contraindicated - pregnancy - young children Thyroid function is brought to normal function prior to surgery (euthyroid state) with thyroid suppression agents

21. 21 Nursing Considerations: hyperthyroid Assess activity level, food intake, body weight Dilute liquid iodine medications Watch for iodism, thyroid storm Patients who have had I131 should avoid children and pregnant women for one week Watch for symptoms of hypothyroidism

22. 22 Thyroid Disorders: Hypothyroidism Decreased secretion of thyroid hormones  Decreased metabolism Clinical signs and symptoms  Thickened skin  Decreased cardiac and respiratory rates  Weight gain  Loss of appetite, anorexia  Muscle weakness  Lethargy

23. 23 Hypothyroidism Nongoitrous Goitrous - enlarged thyroid glands caused by excessive stimulation of TSH Causes many symptoms Cretinism in an infant is the result of absence or atrophy of the thyroid during fetal life

24. 24 Hypothyroidism Called cretinism in children  Underdeveloped growth rate  Low metabolic rate  Mental retardation Called myxedema in adults  Low metabolic rate  Loss of mental and physical stamina  Hair loss, firm edema

25. 25 Hypothyroidism Goal is to replace the thyroid hormone  Levothyroxine sodium (Synthroid) Widely prescribed synthetic thyroid hormone

26. 26 Hypothyroidism Thyroid (levothyroxine sodium) preparations Cause interactions  Oral anticoagulants: increased anticoagulant effect Digitalis: decreased serum levels Hypoglycemic agents: decreased effect

27. 27 Nursing Considerations Assess activity tolerance, food intake, body weight, sleep pattern Take apical pulse for one minute Withhold when heart rate greater than 100 Administer before breakfast Observe for effectiveness of treatment Report toxic signs and symptoms

28. 28 Client Teaching Tips General client teaching tips for clients with thyroid disorders  Too high of a dose will result in nervousness, irritability, and insomnia  Keep a log of pulse, weight, and mood status  Avoid foods high in iodine such as soy, tofu, turnips, seafood, and iodized salt

29. 29 Client Teaching Tips  Immediately report chest pain.  Synthroid takes several weeks to months to reach the therapeutic level.

30. 30 Parathyroid Glands Parathyroid  Pinhead-sized structures located on either side of the thyroid gland Primary function  Parathormone secretion It promotes bone resorption (breakdown of the bone)

31. 31 Parathyroid When calcium increases, PTH decreases and calcitonin is released Calcitonin reduces serum calcium levels All helps to regulate serum calcium levels

32. 32 Hypoparathyroidism Parathormone deficiency Result  Decreased blood levels of calcium  Increased phosphate levels  Neuromuscular irritability  Psychiatric disorders

33. 33 Treatment of Hypoparathyroidism Replenishment of calcium stores During acute stage IV administration of calcium salts Maintenance with oral therapy Vitamin D is also administered to promote absorption of calcium from the GI tract

34. 34 Hyperparathyroidism Oversecretion of parathormone Result  Increased blood levels of calcium  Decreased phosphate levels  Kidney stones Treatment  Replace the calcitonin  Replace the phosphate

35. 35 Treatment of Hyperparathyroidism Often includes surgery Phosphate supplementation Lasix may be given to promote calcium excretion

36. Treatment of Hyperparathyroidism (cont’d) Calcitonin administration Administered subcutaneously or IM Other agents as outlined in book 36

37. 37 Nursing Considerations Assess patient for fatigue, muscle weakness, and other symptoms Calcium preparations should be warmed to body temperature prior to IV administration

38. Nursing Considerations ECG monitoring during calcium administration Patient to remain in bed Oral calcium should not be given with food 38