Agents Affecting Thyroid, Parathyroid, and Pituitary Function

Chapter 34

Agents Affecting Thyroid, Parathyroid, and Pituitary Function  Goal: maintenance of physiologic stability  Hypothalamus and the pituitary gland  Form the neuroendocrine system  Main director is the hypothalamus 2

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 3

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

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

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 6

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

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 8

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

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 10

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

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

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

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

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 15

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 16

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 17

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 18

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 19

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 20

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 21

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 22

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 23

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 24

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

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

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 27

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 28

Client Teaching Tips  Immediately report chest pain.

 Synthroid takes several weeks to months to reach the therapeutic level.

29

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) 30

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

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

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 33

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

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

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

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

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