Pituitary Flashcards

1
Q

What are the 9 endocrine glands?

A
Hypothalamus
Pituitary
Thyroid
Parathyroid
Adrenals
Pancreas
Ovaries
Testes
Pineal Gland
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2
Q

What do the endocrine glands produce?

A

Hormones

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3
Q

In general, what do hormones do?

A

Are secreted into the blood where they affect body tissues or organs (target tissues)

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4
Q

Where do hormones bind?

A

To specific cell receptors either in the cell membrane or inside the cell

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5
Q

What are the two types of hormones?

A

Lipid-soluble
Steroids, thyroid hormones (inactive when bound – must be bound to protein to be transported INTO the cell)
Water-soluble
Protein-based (always active)– attach to cell membrane receptors
They are a 1st messenger that stimulate a 2nd messenger!

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6
Q

What is the most common hormone feedback system?

A

Negative feedback (Low Ca+ levels stimulate PTH to increase Ca+ levels which then inhibits further PTH)

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7
Q

What is complex feedback?

A

When one hormone tells another hormone to act [TRH stimulates TSH; when TSH levels are sufficient – T3 & T4 tell TRH (hypothalamus) & TSH (anterior pituitary) to stop.]

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8
Q

How does the nervous system regulate stress?

A

Tells the adrenal medulla to give up some catecholamines (epinephrine & norepinephrine) to increase HR & BP to better deal with the stress.

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9
Q

What two types of hormone groups are secreted by the hypothalamus?

A

Releasing hormones

Inhibiting hormones

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10
Q

What are the releasing hormones?

A
Corticotropin–releasing hormone (CRH)
Thyrotropin-releasing hormone (TRH)
Growth Hormone releasing factor
Gonadotropin-releasing hormone (GnRH)
Prolactin-Releasing hormone
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11
Q

What are the inhibiting hormones?

A

Somatostatin

Prolactin-inhibiting hormone

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12
Q

What is the “Master” Gland?

A

Pituitary

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13
Q

How many lobes does the pituitary have?

A
Anterior lobe (80% of gland)
Secretes 6 hormones (stimulated by the hypothalamus releasing hormones)
CRH -> ACTH
TRH -> TSH
GH-Releasing factor -> GH
Gonadotropic -> LH & FSH
MSH -> melanocytes
Prolactin releasing hormone -> prolactin
Posterior lobe
Secretes 2 hormones (made by hypothalamus but stored here)
Oxytocin
ADH
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14
Q

What are some things that stimulate ADH?

A
Increased plasma osmolality
Decreased fluid volume
Hypotension
Pain
N/V
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15
Q

What are some things that inhibit ADH?

A

Decreased plasma osmolality
Increased fluid volume
B-adrenergic agonists
Alcohol

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16
Q

What are the 3 problems that can occur in the anterior pituitary?

A

Hyperpituitarism
Hypopituitarism
Compression of cerebral tissue

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17
Q

What is the most common cause of pituitary problems?

A

Benign tumor (adenoma)

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18
Q

What are the anterior and posterior pituitary disorders?

A

Anterior
- Hyperpituitarism (GH excess, acromegaly/gigantism
- Hypopituitarism 
Posterior
- Hyper = SIADH
- Hypo = DI

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19
Q

What is the most common cause of hyperpituitarism?

A

Excess secretion of growth hormone & prolactin

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20
Q

What most often causes excess GH and prolactin?

A

Pituitary tumor

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21
Q

What does this GH and prolactin cause in the adult & why?

A

Acromegaly – epiphyseal plate is closed so bones can’t get longer; instead have thickened bones & tissues

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22
Q

What does this cause in children & why?

A

Gigantism – epiphyseal plate is still open so long bone growth occurs

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23
Q

What are the hallmark manifestations of acromegaly?

A

Enlargement of hands/feet
Mandible enlargement
Coarsening of facial features
Joint pain & deformity

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24
Q

What tests are used in the diagnosis of acromegaly?

A

IGF-1 levels (more reliable than GH levels)

OGTT (b/c GH is inhibited by glucose)

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25
Q

What is the treatment of choice for reducing GH levels & may cure hyperpituitarism?

A

Tumor removal = Transsphenoidal hypophysectomy
Total gland removal -> need for lifelong hormone replacement (glucocorticoids, thyroid hormone, sex hormones) -> NEED to monitor for hormone insufficiency
May lose FSH & LH -> infertility – assist with grief process

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26
Q

What does the patient need teaching on pre-op transsphenoidal hypophysectomy?

A

Avoid teeth brushing 10 days
Will need oral care Q 4 hours
Avoid coughing , sneezing, straining
NO bending for 2 months!

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27
Q

What will the nurse need to do post-op transsphenoidal hypophysectomy?

A

HOB > 30 (decreases HA which is common)
Monitor neuro status
Monitor for DI (urine output, serum/urine osmolality)
Occurs b/c ADH is stored in posterior lobe or cerebral edema due to manipulation of pituitary

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28
Q

What will be in place when pt returns from surgery?

A

Nasal packing

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29
Q

What should you do if the pt starts having clear nasal drainage?

A

Send to lab to test for glucose

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30
Q

What does a glucose > 30 indicate?

A

CSF leakage

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31
Q

What complaints may mean CSF leakage?

A

Severe headache

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32
Q

How long do leaks take to resolve?

A

Within 72 hours

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33
Q

If a CSF leak occurs, what does the pt need & why?

A

IV Antibiotics to prevent meningitis

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34
Q

If surgery fails or pt isn’t a candidate, what will the pt with hyperpituitarism need? (Note: may also be done to shrink a tumor prior to sx)

A

Radiation therapy

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35
Q

How long can radiation therapy assist with reducing GH levels?

A

Up to 2 years

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36
Q

What can radiation therapy cause?

A

Hypopituitarism (requiring HRT)

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37
Q

What is the most common drug used to tx acromegaly?

A

Octreotide (Sandostatin) – reduces GH levels.

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38
Q

How is octreotide given?

A

Subcutaneously 3x/week

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39
Q

What is another drug alternative?

A

Pegvisomant (Somavert) – blocks action of GH

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40
Q

Which pituitary lobe is affected by hypopituitarism?

A

Anterior lobe

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41
Q

What is the cause of hypopituitarism?

A

A decrease in one or more of the pituitary hormones

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42
Q

What hormones are secreted by the anterior pituitary gland?

A

ACTH, TSH, FSH, LH, GH, prolactin (gonadotropins & GH are most common deficiencies)

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43
Q

What is a deficiency of one of these anterior pituitary hormones called?

A

Selective hypopituitarism

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44
Q

What is a total failure of the pituitary gland called?

A

Panyhypopituitarism (b/c ALL hormones are deficient)

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45
Q

What is the usual cause of hormone deficiency resulting in hypopituitarism?

A

Pituitary Tumor

46
Q

What are the common symptoms of pituitary tumor?

A

HA
Visual changes (decreased peripheral vision, decreased acuity)
Anosmia (loss of smell)
Seizures

47
Q

What is the treatment for hypopituitarism?

A

Sx or Irradiation (tumor removal) -> lifelong HRT

48
Q

What is the usual HRT for GH deficiency?

A

Somatropin (Omnitrope, Genotropin, Humatrope)

49
Q

What would you expect to see with GH HRT?

A

Increased energy
Increased lean body mass
Feeling of well-being
Improved body image

50
Q

How is Somatropin given?

A

Daily subcutaneous (preferably in the evening)

51
Q

How is Somatropin dosing adjusted?

A

Relief of symptoms
IGF-1 levels
Development of adverse effects

52
Q

In pts with gonadotropin deficiency, which pts should not receive HRT?

A
Breast CA, Phlebitis, PE (in women)
Prostate CA (in men)
53
Q

What hormones does the posterior pituitary store and release?

A

ADH & Oxytocin

54
Q

What gland produces these hormones?

A

Hypothalamus

55
Q

What syndrome occurs with the overproduction of ADH?

A

SIADH

56
Q

What syndrome occurs with the underproduction of ADH?

A

DI

57
Q

If the pituitary quits functioning, will the hormones still be produced?

A

Yes (because the hypothalamus is still working)

58
Q

What does ADH do?

A

Regulates water balance and osmolarity (regulates renal retention & excretion of water)

59
Q

What is another name for ADH?

A

Vasopressin

60
Q

What happens in SIADH?

A

There is more ADH then normal -> decreased urine output & fluid retention

61
Q

What happens in DI?

A

There is not enough ADH -> increased urine output & dehydration

62
Q

Which of the posterior pituitary disorders is a common cause of dilutional hyponatremia?

A

SIADH

63
Q

If the patient is retaining urine, what will the urine produced look like?

A

Concentrated

64
Q

What is the most common cause of SIADH?

A

Malignancy

65
Q

So if no other reason can be found for SIADH, what should the pt be evaluated for?

A

Presence of cancer (CA)

66
Q

If SIADH is caused by head trauma or drug-induced, it is usually

A

self-limiting

67
Q

If SIADH is caused by malignancy, it is usually

A

chronic

68
Q

What are the early signs of hyponatremia?

A

Thirst

Exertional dyspnea
Fatigue

69
Q

What are the late signs of hyponatremia

A

Muscle cramping
Pain
Weakness

70
Q

So if the body is retaining urine, what will happen with the body weight?

A

Increase

71
Q

If sodium continues to fall (< 120 mEq/L) what may occur?

A

N/V, abd cramps, muscle twitching, seizures

Cerebral edema à lethargy, confusion, HA, coma

72
Q

How is SIADH diagnosed?

A

Simultaneous measurement of urine and serum osmolality
Na < 135 mEq/L
Serum osmolality < 280 mOsm/kg
Urine specific gravity > 1.005 (concentrated!)
Will have decreased BUN, Cr, H & H (hemodiluted!)

73
Q

How is SIADH treated?

A

Treat the underlying cause! (If it’s a tumor, remove or irradiate it!)

74
Q

Which medications stimulate ADH release & should be avoided in these pts?

A
Oxytocin
Carbamazepine (Tegretol)
Chlorpromadmide (Diabinese)
Anesthetics & Opioids
Thiazides
SSRI & Tricyclic antidepressants
Antineoplastic agents
75
Q

What is the immediate treatment goal of SIADH?

A

Restore fluid volume and osmolality
Mild to moderate (> 125 mEq/L) = Fluid restriction 800-1000 mL/day; Possibly loop diuretic
Severe (< 125 mEq/L) = IV hypertonic saline (3-5%) on (SLOW) infusion pump w/ Fluid restriction 500 mL/day

76
Q

If you give the pt Lasix (furosemide), what might they need supplements of?

A

Potassium, Calcium, Mg – (due to increases losses!)(With meals!)

77
Q

If the pt has chronic SIADH, what is the recommended tx?

A

800-1000 mL/day; If not tolerated, give demeclocycline (Declomycin) – blocks affects of ADH on renal tubules (Must be given in monitored setting to avoid increasing Na+ too rapidly!)

78
Q

What should the pt with chronic SIADH be taught?

A

Increase K+ in the diet

Weigh daily & report any sudden changes

79
Q

What should the nurse be assessing for in SIADH?

A

Hourly: Vital signs, urine output, urine spec gravity
Routine: Neuro status, electrolyte lab values
Daily: Weight

80
Q

If the pt is on fluid restriction, what care does the pt need?

A

Frequent mouth rinses / oral care

81
Q

If pt has chronic SIADH, what should you teach them?

A

Fluid restrict of 800-1000ml/day
Use ice chips or sugarless gum to decrease thirst
S/S electrolyte imbalances (esp Na & K)

82
Q

What disorder is caused by a deficiency in or a decrease in renal response to ADH?

A

Diabetes Insipidus (DI)

83
Q

What is the main result of DI?

A

Increased urine output & increased plasma osmolality (Dilute urine! – and lots of it [up to 20 L/day])

84
Q

There are several classifications of DI. Which one occurs due to a lesion of the hypothalamus, infundibular stem, or posterior pituitary, or head trauma, or sx?

A

(It is the most COMMON form & is secondary b/c something else has caused it!) Central DI (Neurogenic DI)

85
Q

What type of DI occurs when there is adequate ADH but decreased response to it by the kidney?

A

NEPHROgenic DI

86
Q

What are the most common causes of nephrogenic DI?

A

Lithium, Hypokalemia, Hypercalcemia

87
Q

What type of DI occurs due to excessive water intake?

A

Primary DI (also called psychogenic)

88
Q

What are the two main characteristics of DI?

A

Polyuria & Polydipsia

89
Q

What would you expect to see with the urine?

A

Specific gravity < 1.005 (diluted!)

Decreased urine osmolality

90
Q

The patient with DI, will have what electrolyte imbalance?

A

Hypernatremia

91
Q

What would you expect serum osmolality to be?

A

Increased (> 295 mOsm/kg)

92
Q

What will happen if fluid intake is low & the pt is urinating massive amts of urine?

A

Severe FVD

93
Q

What s/s would you expect to see?

A

Weight loss, constipation, decreased skin turgor, hypotension, tachycardia -> CNS irritability, decreased LOC -> shock -> coma -> eventual vascular collapse

94
Q

What is the initial step in treating DI?

A

Figuring out the cause to ID which type it is

95
Q

Which type of DI is due to overhydration & hypovolemia? (NOTE: The other two are due to underhydration & hypovolemia)

A

Primary (psychogenic) DI

96
Q

What test is given to confirm central (neurogenic) DI?

A

Water deprivation test

97
Q

How does this test rule out nephrogenic DI?

A

Because ADH is given & will not restore urine osmolality such as it will in central DI

98
Q

What baselines must be obtained prior to a water deprivation test?

A

Weight, pulse, urine & plasma osmolality, urine specific gravity, BP

99
Q

What should the pt be instructed about prior to the water deprivation test?

A

No fluid intake 8-16 hours prior to the test

100
Q

What will you assess hourly during the water deprivation test?

A

BP, weight, urine osmolality

101
Q

How long does the water deprivation test continue?

A

Until urine osmolality stabilizes (hourly increase < 30 mOsm/kg in 3 consecutive hours OR weight declines by 3% OR orthostatic hypotension occurs)

102
Q

Once osmolaltiy is stable, what is given to the pt?

A

Vasopressin (ADH) – urine osmolality checked 1 hour later

103
Q

What is the tx for nephrogenic DI?

A
Low-sodium diet (helps decrease u/o)
Thiazide diuretics (reduces flow to ADH-sensitive distal nephrons)
IF the 1st two are ineffective à Indomethacin (Indocin) given (increases renal response to ADH)
104
Q

What is the hormone replacement of choice for central (neurogenic) DI?

A

Desmopressin acetate (DDAVP)

105
Q

What other meds may be used to tx central DI?

A

Pitressin (vasopressin)
chlorpropamide (Diabinese)
carbamazepine (Tegretol)

106
Q

When giving DDAVP, what do you need to assess?

A

Response – any wgt gain, HA, restlessness, s/s hyponatremia, water intoxication
Intake & Output, urine specific gravity

107
Q

Why do you need to monitor the urine specific gravity with DDAVP?

A

If pt develops increased u/o with low specific gravity  call physician immediately (indicates need for increased dosing of DDAVP)

108
Q

What nursing mgt is needed for DI?

A

Strict I & O
Keep cold fluids of pts liking at bedside; offer frequently
Monitor electrolytes closely; replace PRN
Daily wgt
S/S FVD (tachycardia, weak thready pulse, hypotension, etc)
Titrate IVF to urine output
Hypotonic saline or
D5W (if used, monitor glucose levels!)

109
Q

What can hyperglycemia & glucosuria lead to?

A

Osmotic diuresis -> increasing FVD

110
Q

Why is the pt with DI at risk for disturbed sleep pattern?

A

Nocturia