Lec 2 Hypopituitary Flashcards

1
Q

Where are posterior pituitary hormones made?

A

made in hypothalamus; stored in pituitary

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2
Q

Is hypopituitarism vs end organ hormone deficiency more severe?

A

end organ deficiency is more severe –> in absence of pituitary trophic hormones end organs will still continue to secrete some hormone

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3
Q

What are 3 causes of hypopituitarism?

A
  • primary pituitary disorder = loss of hormone secreting cells
  • hypothalamic disorder = loss of releasing hormones
  • extrinsic destruction of hypothalamus/stalk/pituitary gland
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4
Q

What is embryology of anterior pituitary?

A

derived from rathkes pouch = ectodermal pouch of primordial oral cavity

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5
Q

What is embryology of posterior pituitary?

A

direct extension of nervous system

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6
Q

What is a cranyopharyngioma?

A

tumor derived from remnants of rathkes pouch

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7
Q

What is the one exception to the rule that all of the hormones secreted from hypothalamus are peptides?

A

dopamine = modified tyrosine molec

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8
Q

Which part of pituitary connects to hypothalamus via capillary portal system?

A

anterior pituitary

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9
Q

What two hormones are secreted by posterior pituitary?

A
  • ADH/vasopressin

- oxytocin

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10
Q

What are x etiologies of hypopituitarism?

A
  • invasion [tumor/cystic lesion]
  • iatrogenic [surgery/radiation]
  • infiltration [sarcoid, hemochromatosis]
  • infarction [postpartum sheehans]
  • injury [head trauma]
  • infection [TB, syphilis]
  • immune [autoimmune
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11
Q

What type of cell secretes growth hormone?

A

somatotroph

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12
Q

What type of cell secretes TSH?

A

thyrotroph

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13
Q

What type of cell secretes LH/FSH?

A

gonadotroph

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14
Q

What type of cell secretes ACTH?

A

corticotroph

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15
Q

What type of cell secretes prolactin?

A

lactotroph

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16
Q

What is action/target organs of growth hormone?

A

stimulates linear growth and muscle mass by causing secretion of IGF1[somatomedin]

anti-insulin effects

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17
Q

What are 4 actions of T3/T4?

A
  • thermogenesis = increase BMR via Na/K ATPase
  • increase B1 receptors in heart –> increase CO/HR/SV
  • bone growth
  • CNS maturation
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18
Q

What is action of ADH?

A

regulates serum osmolarity and BP –> decreases serum osmolarity and increases urine osmolarity via aquaporins in kidney

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19
Q

What is action of prolactin?

A

stimulates milk production

inhibits ovulation and females and spermatogenesis in males by inhibiting GnRH synthesis and release

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20
Q

Where is anterior pituitary located?

A

sella turcica

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21
Q

What is action of LH?

A

stimulates sex steroid hormone synthesis in gonads

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22
Q

What is action of FSH?

A

follicular development in females; spermatogenesis in males

23
Q

What is regulation of prolactin?

A

under tonic inhibition from dopamine –> only secrete prolactin when really low dopamine

high TRH can also stimulate prolactin

24
Q

What 2 things stimulate prolactin secretion?

A
  • suckling

- high estrogen

25
Q

What is structure of FSH/LH/TSH/HCG?

A

glycoprotein hormones with alpha and beta subunits

same alpha; different beta

26
Q

What is order of loss of pituitary hormones [ACTH, FSH, GH, LH, TCH]?

A

first: GH –> FSH/LH –> TSH –> ACTH

27
Q

What condition can present with isolated ACTH deficiency?

A

hypophysitis

28
Q

What is effect of loss of posterior pituitary hormones?

A

diabetes insipidus

29
Q

What is pituitary apoplexy? presentation?

A

sudden hemorrhage into pituitary –> severe headache, double vision, acute onset hypopituitarism; sudden onset ACTH deficiency –> severe hypotension

can be due to pituitary adenoma

30
Q

What is major cause of hypopituitarism in adults?

A

pituitary tumor or treatment of pituitary tumor

31
Q

What is sheehan’s syndrome? early sign?

A

pituitary infarction from massive blood loss during childbirth

early sign = inability to lactate after childbirth

32
Q

What are 3 mass-effect symptoms of pituitary sella tumors?

A

headahce, bitemporal heminopia, galactorrhea

33
Q

What are symptoms of pan-pituitary hormone deficiency?

A
  • amenorrhea or erectile dysfunction
  • wrinkling of skin
  • loss of axillary and pubic hair
  • low BP from low cortisol
  • loss of lateral eyebrows
  • sallow complexion
  • more fat / less muscle
34
Q

How does pediatric hypopituitarism present?

A
  • abnormal growth / falling off growth curve

- can also see isolated deficiencies from congenital releasing hormone deficiencies

35
Q

What do you see in pediatric GH deficiency?

A

unexplained short stature

36
Q

What are x causes of pediatric GH deficiency?

A
  • isolated GHRH deficiency
  • pituitary tumor
  • GH insensitivity [laron dwarf]
37
Q

What lab levels do you see in laron dwarf?

A

high GH but not IGF1 = absent GH receptor

38
Q

How do you test for pediatric GH deficiency?

A

give GHRH and measure GH response

39
Q

What do you see in pediatric gonadotropin deficiency?

A

abnormal 2ndary sex characteristics [microphallus] or failure to sexually mature at expected time

have long arms and legs b/c low sex steroids which are responsible for puberty growth spurt

40
Q

What are two causes of pediatric gonadotropin deficiency?

A
  • kallmann syndrome = GnHr deficiency

- tumor damaging gonadotrophs

41
Q

What disease is characterized by anosmia + failure to sexually mature at expected time?

A

kallman syndrome

42
Q

What do you see in craniopharyngioma?

A

tumor causes delay or absence of pubertal development

seen in kids

have short stature and severe hypogonadism

tumor = has lots of calcification b/csimilar origin to teeth

43
Q

What is another name for posterior pituitary?

A

neurohypophysis

44
Q

What is action of oxytocin?

A

release of milk from breast

uterine contraction at childbirth

45
Q

What are two causes of diabetes insipidus?

A
  • deficiency in ADH secretion from PP

- resistance to ADH at level of kidney

46
Q

What are symptoms of diabetes insipidus?

A
  • polyuria [> 3 L/day]

- inability to concentrate urine despite increase in plasma osmolality

47
Q

What must be ruled out when you think diabetes insipidus?

A

psychogenic polydipsia

48
Q

What are causes of central diabetes insipidus?

A

due to ADH deficiency

  • pituitary stalk transection
  • post-pituitary surgery
  • autoimmune
  • malignancy
  • familial
49
Q

What are causes of nephrogenic diabetes insipidus?

A

vasopressin resistance

  • hereditary [ADH receptor gene mutation]
  • lithium tox
  • hyper-CA
  • hypo-K
50
Q

How do you distinguish central DI vs nephrogenic DI vs psychogenic polydyspia

A

central: on water deprivation, can’t concentrate urine; if administer exogenous ADH [desmopressin] –> improves
nephrogenic: on water deprivation, can’t concentrate urine; no change with exogenous ADH
psychogenic: on water deprivation, urine becomes concentrated + decrease quantity

51
Q

What is microadenoma vs macroadenoma of pituitary?

A

microadenoma < 1 cm

macroadenoma > 1 cm

52
Q

What hormone should be replaced first in hypopituitarism?

A

replace cortisol first

53
Q

What are 4 things that inhibit ADH?

A
  • adequate water
  • ethanol
  • a-adrenergic agonists
  • ANP
54
Q

What water/Na state cause release of ADH?

A
  • increase serum Na/osmolarity

- low BP/hypovolemia/hemorrhage