Endocrinology I Flashcards
which hormone is responsible for directly stimulating tissue growth?
IGF-1 whose secretion is stimulated by GH
what type of cell makes up most of the pituitary gland?
somatotroph (50%)
what type of cell is the least abundant in the pituitary gland?
thyrotrophs (<10%)
what is the most common type of hormone secreting pituitary tumor?
prolactin
how would you classify most pituitary tumors?
non-malignant (benign)
- non functioning (don’t affect hormone levels)
- hyperfunctioning
what is the size of a microadenoma?
<1cm
what is the size of a macroadenoma?
> 1cm
what are common signs and sxs that go along with pituitary tumors?
- visual field defects
- N/V
- H/A
- hormone specific sxs
what is the most common type of pituitary tumor overall?
non-functioning
micro>macro
what is unique about LH/FSH secreting tumors?
the hormones secreted are not effective, therefor do not produce any clinical manifestations
what is the most common way that microadenomas are found?
incidental finding from a scan that was taken for another reason
what is included in the initial pituitary work up?
- all ant. pit. hormones
- target organ hormones (free T4, cortisol, sex hormones, IGF-1)
- MRI of pit and hypothalamus (w/contrast)-NOT of the WHOLE BRAIN
- ophthalmology referral for pt with macroadenoma and field defects
when is surgery recommended?
- symptomatic tumors
2. macroadenomas
why does reglan cause hyperprolactinemia?
it is a dopamine antagonist
-dopamine secretion inhibits prolactin release
what is a normal prolactin level?
> 30
what action does GH oppose?
insulin action
is considered to be diabetogenic
hypogylcemia will do what to GH?
stimulate it
hyperglycemia will do what to GH?
suppress it
what are the nine I’s of hypopituitarism?
invasive (*pit tumor) infarction (*CVA) injury (*brain trauma) invasive immunologic iatrogenic (*post surgical, radiologic) infetious idiopathic isolated
which gland is the problem in primary hypothyroidism?
thyroid gland
which gland is the problem in secondary hypothyroidism?
pituitary
how would you describe a diffuse goiter?
whole gland enlargement
-Grave’s dz, Hashimotos, endemic goiter
how would you describe a heterogenous goiter?
multinodular goiter
how would you describe a solid nodule goiter?
benign nodules vs cancer?
solitary nodule
which thyroid tests are most commonly used?
TSH (thyrotropin)
free T4
why do we test for free T4?
results of a total T4 will change in connection with albumin levels
what could increase TBG levels?
estrogen
OCP/Pregnancy
when would you use thyroglobulin level test?
post thyroid cancer treatment follow up
when would you use calcitonin?
screening for medullary carcinoma
what imaging study is the best one to determine thyroid anatomy?
ultrasound
-determines size of nodule and/or if it is cystic or solid
what are the inactive metabolites of epi and norepi?
metanephrine
normetanephrine
what is the 10% rule of pheochromocytoma?
bilateral malignant extra adrenal pediatric familial
