Flashcards in Disorders of the Pituitary Gland Deck (74)
What does the anterior pituitary do?
Synthesize and secrete hormones in response to negative feedback from adrenals, thyroid and gonads
What are the anterior pituitary hormones?
Thyroid stimulating hormone
Follicle stimulating hormone
What does ACTH do?
Increase production and release of cortisol by the adrenal cortex (cortisol negatively feedbacks on it)
What does TSH do?
Stimulate thyroid gland to produce T4 and T3 to stimulate the metabolism of many tissues
What does LH do?
Trigger ovulation and development of corpus luteum and stimulate production of testosterone
What does FSH do?
Stimulates growth of ovarian follicles (F) or stimulates formation of secondary spermatocytes (M)
What does GH do?
Stimulate growth, cell reproduction, cell regeneration and gluconeogenesis
What does prolactin do?
Stimulates milk production (F) or works with LH and testosterone to increase reproductive function (M)
What is different about the posterior pituitary?
It does not synthesize hormones, it just stores ADH and oxytocin which are made in the hypothalamus
What does ADH do?
Released in response to hypertonicity and causes kidneys to reabsorb water (concentrated urine and reduce urine vol)
What does oxytocin do?
Increase uterine contractions and promote stretching of cervix and uterus during labor
What does the intermediate pituitary do?
Synthesize and secrete melanocyte-stimulating hormone to control skin pigmentation
Presentation of a sellar mass
Neuro sxs (vision changes, HA)
Incidental MRI finding
Most common visual complaint of sellar masses
Bitemporal hemianopsia (suprasellar extension of adenoma leading to compression of optic chiasm)
Etiologies of sellar masses
Benign: pituitary adenomas, craniopharyngioma, meningioma
Cysts, abscesses, AV fistula of cavernous sinus
Malignant tumors: primary like germ cell tumor, chordoma, lymphoma or mets from breast or lung cancer
Most common primary pituitary tumor
Micro vs macroadenoma
Micro <1 and macro >1
Features of pituitary adenoma due to gonadotrophs
Non-functioning meaning no hormonal related role
Features of pituitary adenoma due to thyrotrophs
Increased TSH secretion
Features of pituitary adenoma due to corticotrophs
Increased cortisol causes Cushing's (these make ACTH)
Features of pituitary adenoma due to lactotrophs
Increased prolactin causes hyperprolactinemia (and therefore hypogonadism)
Features of pituitary adenoma due to somatotrophs
Increased GH causes acromegaly
How to diagnose a sellar mass
MRI of the brain
Hormonal hypersecretion tests (serum prolactin and IGF-1, 24 hr urine cortisol, T3/T4/TSH)
Prolactinoma in premenopausal women
Infertility, oligomenorrhea/amenorrhea, galactorrhea
Serum prolactin >30 ng/mL
Prolactinoma in postmenopausal women
HA, impaired vision, galactorrhea (rare)
Later findings and bigger mass b/c don't see things like amenorrhea
Serum prolactin >20ng/mL
Prolactinoma in men
Decreased libido, impotence, infertility, gynecomastia, galactorrhea (rare)
Serum prolactin >20 ng/mL
Causes of hyperprolactinemia
Pregnancy, stress, lactation, exercise, drugs (phenothiazine, haloperidol, benzos), pathologic (micro and macro, hypothyroidism)
Medical tx for prolactinoma
Bromocriptine or Cabergoline (dopa agonist to stop action of prolactin)
Surgical tx of prolactinoma
Transsphenoidal resection (if small) or radiotherapy