Chapter 35 Agents Affecting Thyroid, Parathyroid, and Pituitary Function

Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved 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

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

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

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

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

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

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

Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved 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 (continues)

Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved Antithyroid Drugs Methimazole and propyithiouracil (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 (continued)

Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved 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 (continues)

Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved 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 (continues) (continued)

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

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

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  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 Client Teaching Tips  Immediately report chest pain.  Synthroid takes several weeks to months to reach the therapeutic level. (continued)

Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved 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)

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

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

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

Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved 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 (continued)

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  Focus is on water versus sodium Causes vasoconstriction Synthetic ADH drugs  Lypressin  Vasopressin