Pituitary Gland Flashcards
what is the infundibulum?
the stalk that attaches the hypothalamus to the pituitary gland (sits in the sella turcica)
what hormones does the anterior Pit secrete?
ACTH, TSH, LH, GH, FSH, PRL
what hormones does the posterior pit secrete?
oxytocin and ADH
what does the intermediate lobe produce?
melanocyte-stimulating hormone that controls skin pigmentation
GH excess
benign pituitary adenoma, a mixed cell tumor, or ectopci tumors (islet cell type) or MEN type I
what does a pit. adenoma secrete?
> 1 cm, stimulates GH release that then stimulates the relase of insulinlike growth factors from the liver
what accounts for 10-15% of pituitary tumors?
somatotrph-producing tumors
what are mixed cell tumors often associated with?
PRL secretion
what is gigantism?
occurs in children prior to closure of the epiphyses and causes excess growth of long bones (super rare)
what is acromegaly
causes enlargement and elongation of the hands, feet and jaw and internal organs
when is the onset of acromegaly?
in the 30s so it doesn’t affect long bones
what are other features of acromegaly?
- increased risk of DM. HTN, CAD
- doughy, moist hands
- macroglossia
- carpal tunnel syndrome,
- deep, coarse voice
- obstructive sleep apnea
- goiter
- HTN and cardiomegaly
- weight gain and insulin resistance
- arthralgias and arthritis
- colon polyps
- hyperhidrosis
- cystic ance
- acanthosis nigrican
- HA
- spinal stenosis
- tmeproal hemainopsio
- decreased libido
- ED
- menstural abnormalites
what is a common organ finding upon dx of acromegaly?
overt heart failure w/ dilated left ventricle and reduced EF
dxof GH excess
if IGF-1 is elevated fivefold, them suggests adnemoa
PRL levles are also measure
-randome GH levels aren’t accurate
what would a 1 hour glucose tolerance test show?
failure of GH to decrease to 2 ug/L after 75 g loading dose
what is the modality of choice when dx GH excess?
MRI- negative scan virtually r/o GH pit adenoma
skull radography often shows enalarged sella and thickened skull
what might an xray of the hands and feet reveal?
tufting of the terminal phalanges
tx of GH excess?
somatostatin analogs
ocreotide and lanreotide are inhibiory and may decrase tumor size
what can be used for pts that fail surger?
DA agonist like cabergoline or bromocriptine 9supress GH levels)
what is the most successful surger in pts w/ GH blood levels below 50 and tumors no larger than 2 cm?
transphenoidal microsurger
what ist he best measure of surgical success in GH excess?
normilization of IGF-I
what is pegvisomant?
a GH receptr antagonist that blocks hepatic IGF-1 production- sx relieft
Diabetes Inspidus
-insipid- tasteless (as opposed to sweet0mellitus)
what is DI caused by?
deficiency of or resistance to vasopressin (ADH)
