Disorders of Anterior Pituitary 1 Flashcards
what is the most common pituitary tumor
- prolactinoma
75% of the nonsecratory tumors involve which subunit
- alpha
prolactin stimulates what process
- milk production by an estrogen primed mammary gland
prolactin decreases levels of
- gonadotropins (LH and FSH) by inhibiting GnRH
- and estrogen
estrogen (stimulates/inhibits) prolactin
- stimulates
what hormone from the hypothalamus stimulates release of prolactin
- TRH (due to hypothyroidism)
- has no true release hormone though
drugs that can cause hyperprolactinemia
- antihypertensives (verapamil)
- GI (metoclopramide, H2 blockers)
- antipsychotics
- antidepressants
clinical manifestations of hyperprolactinemia in women
why
- galactorrhea (due to increased prolactin)
- amenorrhea (due to decrease of estrogen)
- infertility (loss of mid cycle surge of LH and FSH)
- osteoporosis (loss of protective estrogen effect)
clinical manifestations of hyperprolactinemia in men
- impotence
- visual field abnormalities
- headache
- extraocular muscle weakness
what is oligomenorrhea
how does hyperprolactinemia cause this
- infrequent menstruation
- progressive increase in prolactin results in defective LH and FSH secretion which results in lower estrogen (because FSH produces estrogen)
tests to order when assessing for hyperprolactinemia
- prolactin
- FSH/LH
- TSH
- creatinine (rule out renal failure)
- pregnancy test
history when assessing for hyperprolactinemia should focus on
- medication usage
in hyperprolactinemia, assess visual fields when MRI shows
- optic chiasm compression
how does craniopharyngioma cause hyperprolactinemia
- inhibit dopamine release from hypothalamus `
treatment for pathological hyperprolactinemia
- dopamine agonist therapy
- surgery and radiotherapy have limited use
what dopamine agonists do we give for treatment of hyperprolactinemia
- cabergoline
- bromocriptine
side effects of dopamine agonist therapy
- nausea/vomiting
- orthostatic hypotension
Acromegaly is due to
- excessive growth hormone secretion
- generally due to pituitary adenoma
pathologic changes due to acromegaly
- acral (peripheral body parts) changes (prominent chin and increased hand size)
- sweating
- thickening of skin
- hypertension
- neoplasia
- cardiomyopathy
how do we diagnose acromegaly
- measure IGF-1 levels (will be high since GH stimulates release of IGF-1) - FIRST LINE
- measure GH levels after glucose administration (normally should decrease as GH decreases after glucose admin. in patients with acromegaly, it will remain a high level)
growth hormone is most commonly released at what point during the day
- at night during sleep
acromegaly with what condition has the lowest survival
- cardiac disease
goals of acromegaly treatment
- return life expectancy to normal
- restore normal levels of GH and IGF-1
treatment for acromegaly
- surgery (transsphenoidal hypophysectomy) FIRST LINE
- radiotherapy - delayed response of tumor and you destroy the pituitary
- medical therapy
