Download Agents Affecting Thyroid, Parathyroid, and Pituitary Function

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




Form the neuroendocrine system
Main director is the hypothalamus
35 - 2
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
Pituitary Gland
Consists of:





35 - 3
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.
(continued)
Hormones secreted by the anterior pituitary
35 - 4
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 T3 and T4 hormones


Cellular metabolism
Produces calcitonin

Inhibits bone resorption
35 - 5
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
Thyroid Disorders


Hyperthyroidism
Hypothyroidism
35 - 6
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
Hyperthyroidism

Excessive secretion of thyroid
hormones

35 - 7
Increased metabolism
(continues)
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
(continued)
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
35 - 8
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
Antithyroid Drugs

Inhibits coupling of iodine


Prevent T3 and T4 formation
Iodides

Stop thyrotropin from being active


Radioactive isotopes

Diagnose and treat hyperthyroidism

35 - 9
Inhibits the production of T3 and T4
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



Liver and bone marrow toxicity
Interactions



Increased activity of oral anticoagulants
Additive agranulocytosis when taken with
bone marrow depressants
Therapeutic results


Normal metabolic rate
35 - 10
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
Hypothyroidism

Decreased secretion of thyroid hormones


Clinical signs and symptoms






35 - 11
Decreased metabolism
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




Called myxedema in adults




35 - 12
Underdeveloped growth rate
Low metabolic rate
Mental retardation
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 the thyroid hormone



35 - 13
Levothyroxine sodium (Synthroid)
Widely prescribed synthetic thyroid
hormone
(continues)
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
(continued)
Hypothyroidism
Thyroid (levothyroxine sodium)
preparations
Cause interactions



Oral anticoagulants: increased anticoagulant
effect


Digitalis: decreased serum levels
Hypoglycemic agents: decreased effect
35 - 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




35 - 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 the therapeutic level.
35 - 16
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)
35 - 17
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
35 - 18
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
35 - 19
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
Pituitary Disorders

Hypopituitarism


Therapy



35 - 20
Underproduction of pituitary hormones
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



Treatment



35 - 21
Overproduction of pituitary hormones
Signs and symptoms: gigantism and
acromegaly
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


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
35 - 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



Focus is on water versus sodium
Causes vasoconstriction
Synthetic ADH drugs


Lypressin
Vasopressin
35 - 23
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.