Chapter 20 - Pituitary Flashcards
What does the hypothalamus release?
TRH, CRH, GnRH, GHRH, dopamine into median eminence
What is the path of hormones released from the hypothalamus?
Median eminence, passes through neurohypophysis on way to adenohypophysis
What is the action of dopamine on prolactin?
Inhibits prolactin secretion (bromocriptine analog)
What does the posterior pituitary (neurohypophysis) release?
ADH and oxytocin
What part of the hypothalamus does ADH come from? Regulation?
Supraoptic nuclei; regulated by osmolar receptors in hypothalamus
What part of the hypothalamus does oxytocin come from?
Paraventricular nuclei
What does the anterior pituitary (adenohypophysis) secrete?
FSH, LH, ACTH, TSH, prolactin, GH
Blood supply of the anterior pituitary?
Does not have its own blood supply; passes through neurohypophysis 1st
What is bitemporal hemianopia caused by?
Pituitary mass compressiong the optic nerve at chiasm
How do nonfunctional pituitary tumors present?
Almost always macroadenomas; present with mass effect and decreased ACTH, TSH, GH, LH, FSH
Treatment for nonfunctional pituitary tumors?
Transsphenoid resection
What are the contraindications to transsphenoidal resection?
Suprasellar extension, massive lateral extension, dumbbell-shaped tumor
Medical treatment for TSH- and FSH-/LH-secreting tumors?
Bromocriptine
What is the most common pituitary adenoma?
Prolactinoma
Size of most prolactinomas (micro or macro)?
Microadenomas
Prolactin level in patients (majority) that often have prolactinoma?
> 150
Symptoms of prolactinoma?
Galactorrhea, irregular menses, decreased libido, infertility, decreased vision
Treatment of prolactinoma?
Bromocriptine for most; transsphenoidal rsx for failure of medical management
Treatment for macroadenoma prolactinomas?
Resection with hemorrhage, visual loss, wants pregnancy, CSF leak
Treatment for microadeoma prolactinomas?
Resection if bromocriptine unsafe or ineffective (ok in pregnancy)
Symptoms of acromegaly?
HTN, DM, gigantism
Level of GH in acromegaly?
> 10 in 90%
Preoperative treatment of acromegaly?
Octreotide; may be helpful, inhibits release of GH
Life-threatening complications of acromegaly?
Cardiac symptoms (valve dysfunction, cardiomyopathy)
Diagnosis of acromegaly?
Elevated IGF-1, growth hormone >5-10
Treatment of acromegaly?
Transsphenoidal resection; XRT and bromocriptine as primary or secondary therapy
What is Sheehan’s syndrome caused by?
Pituitary ischemia following hemorrhage and hypotensive episode
1st sign of Sheehan’s syndrome?
Trouble lactating
Other symptoms of Sheehan’s syndrome?
Amenorrhea, adrenal insufficiency, hypothyroidism
What is a craniopharyngioma?
Calcified cyst, remnants of Rathke’s pouch
Symptoms of craniopharyngioma?
Endocrine abnormalities, visual disturbances, headache, hydrocephalus
Treatment for craniopharyngioma?
Surgery, XRT
Frequent postop complication of craniopharyngioma-ectomy?
Diabetes insipidus
What is the workup for bilateral pituitary masses?
Check pituitary axis hormones; if ok, probably mets
When does Nelson’s syndrome occur?
Following bilateral adrenalectomy
What is Nelson’s syndrome?
Increased CRH causing pituitary enlargement, resulting in amenorrhea, visual problems (bitemporal hemianopia)
What is hyperpigmentation from in Nelson’s syndrome?
Beta-MSH, a peptide byproduct of ACTH
Treatment for Nelson’s syndrome?
Steroids
What is Waterhouse-Friderichsen syndrome?
Adrenal gland hemorrhage that occurs after meningococcal sepsis infection; can lead to adrenal insufficiency
