Download Agents Affecting Thyroid, Parathyroid, and Pituitary Function

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
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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
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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
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Hyperpituitarism
 Overproduction of pituitary hormones
 Signs and symptoms: gigantism and
acromegaly
Treatment
 Chemotherapy
 Radiation
 Surgery—inactivation or removal
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Pituitary Disorders
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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
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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
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Thyroid Gland
 Thyroid
gland location: neck
 Produces T3 and T4 hormones
 Cellular metabolism
 Produces calcitonin
 Inhibits bone resorption
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Thyroid
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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
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Thyroid Hormones
 Regulate
lipid and carbohydrate
metabolism
 Essential for normal growth and
development
 Affect heat production in the body
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Thyroid Hormones
(cont’d)
Promotes metabolic breakdown of
cholesterol to bile acids
 Accelerates utilization of
carbohydrates
 Dysfunction has serious
consequences
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Thyroid Disorders: Hyperthyroidism

Excessive secretion of thyroid
hormones
 Increased metabolism
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Hyperthyroidism: S/S
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
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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
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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
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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
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Sodium Iodide I 131
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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
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Beta-Adrenergic Blocking Agents
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Suppresses signs and symptoms of
hyperthyroidism
- tachycardia
- tremor
- anxiety
Do not inhibit function of the thyroid gland
An adjunct to other forms of therapy
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Surgery
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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
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Nursing Considerations: hyperthyroid
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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
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Thyroid Disorders: Hypothyroidism
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Decreased secretion of thyroid hormones
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Decreased metabolism
Clinical signs and symptoms
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Thickened skin
Decreased cardiac and respiratory rates
Weight gain
Loss of appetite, anorexia
Muscle weakness
Lethargy
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Hypothyroidism
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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
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Hypothyroidism
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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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Nursing Considerations
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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
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Client Teaching Tips
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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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Parathyroid
When calcium increases, PTH
decreases and calcitonin is released
 Calcitonin reduces serum calcium
levels
 All helps to regulate serum calcium
levels
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Hypoparathyroidism
Parathormone deficiency
 Result
 Decreased blood levels of calcium
 Increased phosphate levels
 Neuromuscular irritability
 Psychiatric disorders
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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
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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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Treatment of Hyperparathyroidism
 Often
includes surgery
 Phosphate supplementation
 Lasix may be given to promote
calcium excretion
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Treatment of Hyperparathyroidism
(cont’d)
 Calcitonin
administration
 Administered subcutaneously or
IM
 Other agents as outlined in book
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Nursing Considerations
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Assess patient for fatigue, muscle
weakness, and other symptoms
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Calcium preparations should be
warmed to body temperature prior to
IV administration
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Nursing Considerations
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ECG monitoring during calcium
administration
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Patient to remain in bed
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Oral calcium should not be given with
food
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