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Summer FDTN Exam 2 > Pituitary and Hypothalamus II > Flashcards

Pituitary and Hypothalamus II Flashcards

1
Q

What is the physiology of GH

A

most abundant pituitary hormone, released from somatotrope cells in pulsatile way (stable during day)
half life is 12-16 hours
Secretion stimulated by GHRH (hypo) and inhibited by GHIH (SS)
*Peak level 1 hr after onset of deep sleep

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2
Q

What is IGF-1

A

GH stimulates IGF production in liver
IGF1 stimulates growth in epiphyseal plates of long bones (linear growth in kids)
-When absent= Laron type dwarfism

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3
Q

What are the 3 phases of post-natal growth

A

Infantile: first 2 yrs, rapid growth (30-35 cm)
Childhood: constant 5-7cm/yr (prepubertal dip)
Pubertal: 8-14cm spurt/yr (2/2 increasing gonadal steroids and GH secretion)
-velocity falls to 0 when adult growth is met

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4
Q

Explain constitutional vs genetic short stature

A

Constitutional: 2SD below mean height for kids
Genetic: child grows in parental range, but normal velocity

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5
Q

How do you diagnose short stature

A

H&P (pattern- slow growth progressively deviating from previous growth percentile)
IGF-1 (not GH)
GH stimulation test

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6
Q

What other disease states can cause IGF to be low (besides short stature)

A

Hypothyroidism
DM
Renal failure
-poor nutrition

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7
Q

The gold standard for diagnosing GH deficiency is

A

GH stimulation test! (insulin induced hypoglycemia)
Measure serum glucose and GH before, 15, 30, 60, 90, and 120 min after injecting insulin- If they have a deficiency, GH will not rise when you give insulin
-Can also do with arginine (measure serum GH at 0, 30, 60, 90, 120)
**Must correct thyroid deficiency first

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8
Q

How do you treat GH deficiency

A 
SubQ Somatropin (humatrope pen): qd adults, 3/week kids 
-Kids need to take until they reach puberty, then retest GH deficiency; adults, forever
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9
Q

If you are suspicious of short stature, what do you do

A

get bone age with wrist radiograph
IGF-1
confirm with GH stimulation test
refer to peds endocrine (kids with multiple pituitary deficiency rarely recover as adults)

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10
Q

What is pituitary gigantism

A

excess linear growth 2/2 excess GH secretion (but most kids with tall stature do NOT have pituitary gigantism)
Can be 2/2 GH secreting tumor, or GnRH secreting tumor

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11
Q

Before you are sure it is pituitary gigantism, r/o

A

genetic tall stature
precocious puberty (can block with Luprin)
hyperthyroidism
Klinefelters syndrome (dysmorphic features, neurocog problems)
-get bone age, thyroid function test, sex steroid concentration, karyotype, and GH related studies

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12
Q

What tests can you use to Dx gigantism

A

IGF-1 level: will be high
GH suppression (OGTT**): when you give 75g glucose, GH should fall <2. if higher, then gigantism
MRI w/ and w/o

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13
Q

What is Acromegaly

A

hypertrophic and degenerative injury to soft tissues, joints, heart/CV system, respiratory disturbances, and intermediary metabolism
*MCC is pituitary macroadenoma
Takes 10-12 years before diagnosis is made (avg age 40-45)

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14
Q

What are Sx of acromegaly

A

-enlargement of tongue, liver, spleen, thyroid, salivary glands, kidney, prostate
-OSA, narcolepsy
-low renin, high aldosterone, hypercalcuria, high VD
*enlargement of hand and feet, frontal bossing, jaw malacclusion, arthritis, carpal tunnel, myopathies
Oily skin, skin tags, colon polyps, hyperhidrosis, cardiomyopathy, CHF, L/RVH, HTN
-Menstrual abn, galactorrhea, hirsutism, low libido, ED

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15
Q

Acromegalic lab values include

A

hyperglycemia

hyperprolactinemia

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16
Q

Do acromegalic patients live long

A

2-3x mortality rate 2/2 CVD and cancer
Reduced survival by 10 years
-If you lower GH w/ Tx, mortality returns to normal

17
Q

If you suspect acromegaly, what should you do

A

Get IGF-1 test; if high, OGTT

18
Q

How do you treat Acromegaly (non-pharm, pref)

A
  • *TSS; curative for discrete micro and macro! (complications higher in kids)
  • Radiation: adjunct therapy
19
Q

The great thing about TSS is

A

GH secretion falls to normal w/o loss of other pit hormones
GH falls to nl w/in 1-2 hrs post-op
serum IGF falls to nl in 7-10 days

20
Q

Negative aspects of radiation for excess GH

A

delayes efficacy and panhypopit in kids (GH, gonadotropin, and thyrotropid deficiencies)
learning disabilities, emotional changes, obesity

21
Q

How do you treat acromegaly with meds

A

-Bromocriptine (dopamine analog)
-Octreotide*, Pasireotide (SS analogs):
octeo is short acting and suppresses SSTR2&5
-GH receptor antagonists
*Goal is to get IGF-1 to normal range!
*Bromo+Octreo in kdis is great!

22
Q

Long term acromegaly management is

A

eval GH secretion q3-4 months w/ clinical exams, IGF-1, and OGTT
eval ant pit annually w/ gonadotropin deficiency (amenorrhea, adnrogen deficiency), and thyroixine and cortisol
eval adenoma size w/ MRI yearly for first few years post-op; semi-annual visual field assessment
colonoscopy q3-4 yrs if 50+, annual cardio exam

23
Q

How do you treat different pit/hypothalamus tumors

A

Microadenoma (<10mm): TSS
Macroadenoma: surgery less likely to cure
Giant pit tumor (30-40mm): difficult to manage
Hypothalamic tumor (craniopharyngioma): TSS, transfrontal
Prolactinoma: Meds first!

24
Q

Other treatments for tumors are

A

conventional radiation

gamma knife radiation

25
Q

Hallmark of hypopituitarism is

A

abnormal growth in kids

abnormal menses in women

26
Q

Hypopituitarism patients often look like this

A

slightly overweight, pale, fine wrinkled skin, atrophic genitalia, diminished axillary and pubic hair

27
Q

Genetic causes of hypopituitarism are

A

structural defects
Isolated hormone defect/mutation
intrapituitary tumor
extrapituitary tumor (compresses)
Vascular (sheehan’s syndrome, pituitary apoplexy, ischemic infarct)
Injury: damage to stalk, pit, or hypothalamus

28
Q

What is Kallman’s syndrome

A

Anosmia and hypogonadism 2/2 Low GnRH

29
Q

MCC of hypopituitarism in adults

A 
Pituitary tumor 
pit tumor s/p surgery/radiation 
pit tumor w/ hemorrhage 
Hypothalamic tumor 
Trauma (TBI)
30
Q

Hallmarks of concussion are

A

confusion and amnesia

31
Q

Overview of general tests to get when you suspect…

A

Primary organ failure: measure trophic hormone

Secondary organ failure: measure end-organ

32
Q

How is aging related to hypothalamus and pituitary

A

Menopause (high LH/FSH)
Andropause (decline of LH/FSH, and testosterone in men)
-Decline in E2, T, DHEA- but NOT TSH, T4, cortisol, and PRL

Summer FDTN Exam 2 (11 decks)

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