Chapter 35 Agents Affecting Thyroid Parathyroid and Pituitary

Chapter 35 Agents Affecting Thyroid, Parathyroid, and Pituitary Function

Agents Affecting Thyroid, Parathyroid, and Pituitary Function Goal: maintenance of physiologic stability Hypothalamus and the pituitary gland l l £ £ Form the neuroendocrine system Main director is the hypothalamus 2 Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

Pituitary Gland Consists of: l £ £ Adenohypophysis (anterior pituitary) Neurohypophysis (posterior pituitary) Linked to the hypothalamus Pituitary gland secretes hormones l l 3 (continues) Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

(continued) Hormones secreted by the anterior pituitary 4 Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

Pituitary and Thyroid Glands Pituitary gland l £ Thyroid-stimulating hormone (TSH) Thyroid gland location: neck l £ Produces T 3 and T 4 hormones u £ Cellular metabolism Produces calcitonin u Inhibits bone resorption 5 Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

Thyroid Disorders Hyperthyroidism Hypothyroidism l l 6 Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

Hyperthyroidism Excessive secretion of thyroid hormones l £ 7 Increased metabolism (continues) Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

(continued) Hyperthyroidism Clinical signs and symptoms l £ £ £ £ Skin hot and dry Increased cardiac and respiratory rates Weight loss Increased appetite Muscle weakness Nervousness Irritability Unable to sleep well 8 Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

Antithyroid Drugs Inhibits coupling of iodine l £ Prevent T 3 and T 4 formation Iodides l £ Stop thyrotropin from being active u Inhibits the production of T 3 and T 4 Radioactive isotopes l £ Diagnose and treat hyperthyroidism u 9 Radiation destroys the thyroid gland (continues) Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

(continued) Antithyroid Drugs Methimazole and propyithiouracil (PTU) Side effects/adverse effects l l £ Liver and bone marrow toxicity Interactions l £ £ Increased activity of oral anticoagulants Additive agranulocytosis when taken with bone marrow depressants Therapeutic results l £ Normal metabolic rate 10 Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

Hypothyroidism Decreased secretion of thyroid hormones l £ Decreased metabolism Clinical signs and symptoms l £ £ £ 11 Thickened skin Decreased cardiac and respiratory rates Weight gain Loss of appetite, anorexia Muscle weakness Lethargy (continues) Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

(continued) Hypothyroidism Called cretinism in children l £ £ £ Underdeveloped growth rate Low metabolic rate Mental retardation Called myxedema in adults l £ £ 12 Low metabolic rate Loss of mental and physical stamina Hair loss Firm edema (continues) Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

(continued) Hypothyroidism Goal is to replace thyroid hormone l £ Levothyroxine sodium (Synthroid) Widely prescribed synthetic thyroid hormone l 13 (continues) Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

(continued) Hypothyroidism Thyroid (levothyroxine sodium) preparations Cause interactions l l £ Oral anticoagulants: increased anticoagulant effect u u Digitalis: decreased serum levels Hypoglycemic agents: decreased effect 14 Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

Client Teaching Tips General client teaching tips for clients with thyroid disorders l £ £ £ 15 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 (continues) Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

(continued) Client Teaching Tips £ £ Immediately report chest pain. Synthroid takes several weeks to months to reach therapeutic level. 16 Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

Parathyroid Glands Parathyroid l £ Pinhead-sized structures located on either side of the thyroid gland Primary function l £ Parathormone secretion u It promotes bone resorption (breakdown of the bone) 17 Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

Hypoparathyroidism Parathormone deficiency Result l l £ £ Decreased blood levels of calcium Increased phosphate levels Neuromuscular irritability Psychiatric disorders Treatment l £ Replace the calcium 18 Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

Hyperparathyroidism Oversecretion of parathormone Result l l £ £ £ Increased blood levels of calcium Decreased phosphate levels Kidney stones Treatment l £ £ Replace the calcitonin Replace the phosphate 19 Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

Pituitary Disorders Hypopituitarism l £ Underproduction of pituitary hormones Therapy l £ £ £ 20 Corticosteroids: a life and death issue Thyroid replacement Sex hormone replacement (continues) Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

(continued) Pituitary Disorders Hyperpituitarism l £ £ Overproduction of pituitary hormones Signs and symptoms: gigantism and acromegaly Treatment l £ £ £ 21 Chemotherapy Radiation Surgery—inactivation or removal (continues) Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

(continued) Pituitary Disorders Diabetes insipidus l £ £ Caused by a deficiency or total absence of vasopressin (ADH) Signs and symptoms u u £ Huge urine output (polyuria) Increased thirst (polydipsia) Hypernatremia (increased sodium) Dehydration Treatment: antidiuretic hormone 22 Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.

Antidiuretic Hormone (ADH) Directs the body to retain water and sodium l £ Focus is on water versus sodium Causes vasoconstriction Synthetic ADH drugs l l £ £ Lypressin Vasopressin 23 Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.