chapter 35 agents affecting thyroid, parathyroid, and pituitary function
TRANSCRIPT
Chapter 35
Agents Affecting Thyroid, Parathyroid, and Pituitary Function
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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
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Pituitary Gland
Consists of: Adenohypophysis (anterior pituitary) Neurohypophysis (posterior pituitary)
Linked to the hypothalamus Pituitary gland secretes hormones
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Hormones secreted by the anterior pituitary
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Pituitary and Thyroid Glands
Pituitary gland Thyroid-stimulating hormone (TSH)
Thyroid gland location: neck Produces T3 and T4 hormones
Cellular metabolism
Produces calcitonin Inhibits bone resorption
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Thyroid Disorders
Hyperthyroidism Hypothyroidism
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Hyperthyroidism
Excessive secretion of thyroid hormones
Increased metabolism
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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
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Antithyroid Drugs
Inhibits coupling of iodine Prevent T3 and T4 formation
Iodides Stop thyrotropin from being active
Inhibits the production of T3 and T4
Radioactive isotopes Diagnose and treat hyperthyroidism
Radiation destroys the thyroid gland
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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
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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
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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
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Hypothyroidism
Goal is to replace the thyroid hormone Levothyroxine sodium (Synthroid)
Widely prescribed synthetic thyroid hormone
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Hypothyroidism
Thyroid (levothyroxine sodium) preparations
Cause interactions Oral anticoagulants: increased anticoagulant
effect Digitalis: decreased serum levels Hypoglycemic agents: decreased effect
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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
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Client Teaching Tips
Immediately report chest pain. Synthroid takes several weeks to months to
reach the therapeutic level.
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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)
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Hypoparathyroidism
Parathormone deficiency Result
Decreased blood levels of calcium Increased phosphate levels Neuromuscular irritability Psychiatric disorders
Treatment Replace the calcium
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Hyperparathyroidism
Oversecretion of parathormone Result
Increased blood levels of calcium Decreased phosphate levels Kidney stones
Treatment Replace the calcitonin Replace the phosphate
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Pituitary Disorders
Hypopituitarism Underproduction of pituitary hormones
Therapy Corticosteroids: a life and death issue Thyroid replacement Sex hormone replacement
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Pituitary Disorders
Hyperpituitarism Overproduction of pituitary hormones Signs and symptoms: gigantism and
acromegaly Treatment
Chemotherapy Radiation Surgery—inactivation or removal
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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
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Antidiuretic Hormone (ADH)
Directs the body to retain water and sodium Focus is on water versus sodium
Causes vasoconstriction Synthetic ADH drugs
Lypressin Vasopressin