parathyroid and pituitary Flashcards
What is the ddx for decreased calcium with elevated PTH?
hyperparathyroidism due to malturtion or renal disease (most common), could also be due to malabsorption or calcium wasting drugs
What does PTH do to serum phosphate levels?
decreases them (small net drop- increases loss from kidney, but also increases uptake from intestines)
What is pseudohypoparathyroidism?
hypocalcemia due to tissue nonresponsiveness to PTH. associated with developmental and skeletal abnormalities
What conditions are associated with pseudohypoparathyroidism?
Albright hereditary osteodystrophy
What are lab findings of pseudohypoparathyroidism?
-decr. Ca, incr phosphate, incr PTH; PTH administration does not change serum calcium levels
What are the effects of hyperprolactinemia in men and women?
decreased LH and FSH: causes galactorrhea and amenorrhea in women; gynecomastia, impotence, decr libido in med
What lab findings indicate a prolactinoma?
prolactin >300 and no additional secretion of of prolactin in response to TRH administration
What lab results suggest acromegaly?
increased GH, increased GH 1-2 hrs following a 100 g glucose load (in normal individuals, GH decreases after a glucose load)
What are treatments for acromegaly?
resection of adenoma, DA agonists or octreotide to decr effects. Radiation may be needed if refractory
What are the complications of acromegaly?
cardiac failure, DM, spinal cord compression, vision loss due to pressure of tumor on optic nerve.
Cardiac failure is the most important one
What are underlying causes of hypopituitarism?
tumor, hemorrhagic infarction (ie pituitary apoplexy), surgery, trauma, sarcoid, TB, postpartum necrosis (Sheehan syndrome), or dysfunction of the hypothalamus
How does acromegaly affect glucose levels?
Pts with excess GH have insulin resistance that is similar to that seen in DM2 and 10% develop diabetes`
How do you test if the pituitary is secreting GH?
Give insulin and look for increase. If there is pituitary insufficency, there won’t be an increase in GH secretion
How is ACTH deficiency tested?
-ACTH is low.
-Cortisol does not increase following insulin administration (usually increases at least 10 ug/dL(
0ACTH and 11-deoxycortisol don’t increase after administration of metyrapone?
In what order do hormone defiicencies present in hypopituitarism?
GH, then LH/FSH, then TSH, then prolactin, then ACTH,MSH
