Flashcards in EXAM #1: HYPOTHALAMUS & PITUITARY Deck (23):
What are the two essential anterior pituitary hormones?
What is hypopituitarism?
Insufficient secretion of pituitary hormones resulting from diseases of the hypothalamus or the pituitary.
What are the major causes of hypopituitarism?
1) Tumors, such as nonfunctional pituitary adenomas or craniopharyngiomas (exert pressure on adjacent pituitary cells)
2) Pituitary surgery or radiation
3) Traumatic brain injury and subarachnoid hemorrhage
4) Pituitary apoplexy (sudden hemorrhage into the pituitary gland)
5) Sheehan syndrome
6) Empty sella syndrome
What two anterior pituitary hormones do NOT have simple feedback loops?
What is the clinical consequence of GH and Prolactin not having simple feedback loops?
These hormones are most likely to be in EXCESS
What are the manifestations of excess prolactin?
*Elevated prolactin inhibits GnRH
What are the manifestations of excess GH?
What is prolactin essential for?
What causes hypogonadism in hyperprolactinemia?
Inhibition of GnRH release from hypothalamus
What are the manifestations of hyperprolactinemia in women?
1) Irregular menses
What are the clinical manifestations of hyperprolactinemia in men?
What is the differential diagnosis for hyperprolactinemia?
1) Pituitary adenoma (overproduction)
2) Decreased dopamine inhibitiory action
3) Decreased renal clearance of prolactin
- Primary amyloidosis
What serum concentration of prolactin is diagnostic for a pituitary adenoma?
*Less than 30 is stress, greater than 100 and NOT pregnant is also an adenoma
What drugs most commonly cause hyperporlactinemia?
What is the most common type of pituitary adenoma?
What is the treatment for a micro-prolactinoma?
Bromocriptine (DA agonist)
*Dopamine decreases prolactin
What is the treatment for a macro-prolactinoma?
1) Bromocriptine + Tamoxifen
3) Transsphenodial resection
What is the hallmark symptom of hypoprolactinemia?
Failure to lactate
What is the difference in the outcome of excessive GH secretion occurs in childhood vs adulthood?
How is growth hormone excess diagnosed?
- Increased insulin-like growth factor
- MRI/CT imaging of a pituitary neoplasm.
- Growth hormone suppression test with glucose load*
*Dr. Horner, this is a MUST
In a patient with acromegaly, what screening test should be done more frequently?
How is growth hormone excess treated?
Surgery or radiation* + medication adjuncts
- Octreotide, a somatostatin analogue that inhibits GH release from the anterior pituitary and
- Pegvisomant, a GH receptor antagonist which effectively blocks IGF-1 production.