disorders pituitary gland Flashcards

1
Q

pituitary is attached to the hypothalamus via a stalk called

A

the infundibulum

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2
Q

Pituitary gland lies where in the body

A
  • lies near optic chiasm
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3
Q

What is the most common type of sellar mass

A

pituitary adenoma

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4
Q

sellar masses typically present in one or a combination of what 3 ways

A
  1. with neurologic symptoms, such as visual impairment or HA
  2. as an incidental finding on MRI
  3. with hormonal abnormalities
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5
Q

What visual defect is most common with sellar masses

A

bitemporal hemianopsis

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6
Q

In a lactotroph ademoma, check serum levels

A

prolactin

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7
Q

In a somatotroph ademoma, check serum levels

A
  • IGF-1
  • GH
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8
Q

In a thyrotropin ademoma, check serum levels

A

serum TSH

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9
Q

In a corticotroph ademoma, check levels

A
  • 24 hr urine cortisol
  • serum ACTH
  • serum cortisol
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10
Q

If patient has hormonal hyposecretion (caused by hypothalamic or other pituitary lesion, NOT an adenoma) then get what labs

A
  • FSH
  • LH
  • testosterone, free and total: males
  • estradial, free and total: females
  • vasopressin
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11
Q

What is hte single best imaging study for pituitary mass

A
  • MRI with and w/o gadolinium
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12
Q

differentiate between a microadenoma and macroadenoma

A
  • microadenoma: < 1 cm
  • macroadenoma: > 1 cm
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13
Q

Clincal presentation

  • men: low libido, impotence, infertility, gynecomastia, galactorrhea
  • female: infertility, oligomenorrhea, amenorrhea
  • all: visual disturbances, HA
A

Prolactinoma (lactrotroph adenoma)

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14
Q

If patient has signs and symptoms of prolactinoma, check these things first

A
  1. med use
    • cimetidine, methyldopa, verapamil, antidepressants, estrogen will all increase serum prolactin
  2. pregnant
  3. h/o renal disease: inability to clear prolactin
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15
Q

Serum prolactin levels greater than is consistent with hyperprolactinemia. Levels greater than is consistent with adenoma

A
  1. > 20 ng/mL
  2. > 200 ng/mL
    • as long as pregnancy (-)
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16
Q

Tx of Prolactinoma

A
  • Bromocriptine: Dopamine agonist
    • will shrink tumor to size acceptable for surgery
  • Cabergoline: non ergot dopamine agonist
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17
Q

side effects of Bromocriptine

A
  • nausea, constipation, dizziness, HA
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18
Q

What is the most common complication following transphenoidal resection of prolactinoma

A
  • instability of vasopressin leading to SIADH
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19
Q

Growth hormones excess in children and adults leads to what 2 different conditions

A
  • peds: gigantism
  • adult: acromegaly
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20
Q

Growth hormone is synthesized in . It is released in large pulses. When is the largest peak

A
  • anterior pituitary
  • 1 hr after onset of sleep
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21
Q

What is the most accurate maker for GH

A

IGF-1

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22
Q

List the stimulators of GH

A
  • GHRH
  • sleep
  • exercise
  • hypoglycemia
  • dietary protein
  • estradiol
  • arginine
23
Q

List the inhibitors of GH

A
  • somatostatin
  • circulating concentrations of GH and IGF-1
  • dietary carbohydrates
  • glucocorticoids
24
Q

Acromegaly is most commonly the result of

A

a somatotroph (growth hormone secreting) pituitary adenoma

25
Q

clinical presentation

  • visual field defects
  • LVH, HTN
  • organomegaly
  • OA of large joints, increasing hat size, ring or shoe size, enlarging gap between teeth
A

acromegaly

26
Q

Workup of acromegaly involves

A
  • TSH, GH, IGF-1, CMP, CBC, AM cortisol, ACTH, prolactin, UA, rheumatology panels
  • 2 hr glucose tolerance test
27
Q

what calcium value is consistent with acromegaly

A

hypercalciuria

28
Q

explain the 2 hr glucose tolerance test in relation to acromegaly

A
  • if GH level suppresses to < 1 mcg/L during 2 hrs after glucose administration, then acromegaly is excluded
29
Q

patients with acromegaly are at high risk for

A
  • premature mortality
  • insulin resistance
  • LVH/CHF
  • colon CA
  • musculoskeletal abnormalities
30
Q

What is the most effective tx for rapid reduction of GH in acromegaly

A

surgical management

31
Q

Medical managment of acromegaly

A
  • somatostatin analogues
  • GH receptor agonist
32
Q

List the causes of GH deficiency from pituitary dysfunction

A
  • mass
  • infarction
  • infiltrative
  • genetic
33
Q

List the causes of GH deficiency from hypothalamic dysfunction

A
  • mass
  • infiltrative (sarcoidosis)
  • trauma
  • infection (TB)
34
Q

List the causes of GH deficiency from iatrogenic

A
  • radiation
  • pituitary surgery
  • side effect of uncontrolled DM
35
Q

If patient has any lab abnormalites that point to GH deficiency, need to further confirm with either

A
  1. insulin-induced hypoglycemia (stimulation test)
  2. arginine-growth hormone-releasing hormone **recommended
36
Q

Management of growth hormone deficiency

A
  • do not treat unless confirmed deficiency
  • treat if severe
    • recombinant GH
      • dose based on weight, SQ once daily in evening
37
Q

Define male hypogonadism. Differentiate between primary and secondary

A
  • impairment of either testosterone or sperm production by testis
    • primary: failure of testis (hypergonadotrophic hypogonadism)
    • secondary: defect in HPT axis (hypogonadotrophic hypogonadism)
38
Q

What levels of testosterone, FSH, and LH would you expect to see in

  • primary hypogonadism (hyper)
  • secondary hypogonadism (hypo)
A
  • a) primary:
    • low testosterone
    • high FSH, LH
  • b) secondary:
    • low testosterone
    • low/nml FSH, LH
39
Q

List causes of hypogonadatrophic hypogonadism

A
  • congenital (rare)
  • acquired
    • hypothalamic: impaired GnRH secretion
    • pituitary: suppression of gonadotropins
      • GnRH resistance
      • hyperprolactinemia
      • exogenous steroid
      • chronic narcotic
      • DM
    • pituitary: damage to gonadotroph cells
      • sarcoidosis
      • hemochromatosis
40
Q

clinical presentation

  • change in hair growth or distribution
  • changes in voice
  • decreases muscle mass or strength
  • low libido, ED
  • shrinking testicles
  • visual disturbances
A

hypogonadatrophic hypogonadism

41
Q

if hypogonadism suspected, first obtain what labs

A
  • LH
  • FSH
  • free and total testosterone
    • will tell if primary or secondary
42
Q

If secondary hypogonadism, the get what tests

A
  • prolactin, TSH, CBC< CMP
  • MRI pituitary
43
Q

Before treating patient with hypogonadatrophic hypogonadism, make sure what

A
  • DRE and PSA are within normal limits
44
Q

most common tx of hypogonadatrophic hypogonadism

A
  • androgens intramuscular 200 mg q 2 weeks
45
Q

patients on tx for hypogonadatrophic hypogonadism needs to have what checked

A
  1. CBC q monthly for the first 6 months (risk of erythrocytosis)
  2. free estradiol q 2 months for first 6 months
  3. PSA and DRE annually
46
Q

define panhypopituitarism

A
  • deficient secretion of majority of pituitary hormones
    • TSH, ACTH, GH, FSH, LH, prolactin
47
Q

What is central diabetes insipidus

A
  • insufficient ADH production
    • serum osmolarity is preserved as normal
    • urine is dilute
      • ​urine osmolarity < 300 mOsm/kg
48
Q

ADH levels in central vs nephrogenic DI

A
  • central: ADH is low
  • nephrogenic: ADH high
49
Q

clinical presentation

  • dilute urine and polyuria
  • dehydration
  • intense thirst
A

diabetes insipidus

50
Q

diagnostic work up of Diabetes insipidus (nephrogenic or central)

A
  • 24 hr urine
  • serum electrolytes and glucose
  • urine osmolarity
  • urine specific gravity
  • water deprivation and vasopressin challenge
    • in central will see > 100% increase in urine osmolarity with challenge
    • in nephrogenic will see no elevation in urine osmolarity
51
Q

tx of central DI

A

desmopressin (DDAVP)

52
Q

tx of nephrogenic DI

A
  • indomethacin with
    • HCTZ
    • DDAVP
53
Q

What is SIADH and how does it present

A
  • excessive production of ADH
  • concentrated urine
  • hyponatremia