Prep for USMLEPrep for USMLE
         Forum      |     Resources New Posts   |   Register   |   Login





 is metapyrone test useless?  



Post Reply  
  • 0/5
  • 1
  • 2
  • 3
  • 4
  • 5


Author4 Posts
  #1

I don't know why metapyrone test is used. I think it is completely useless test, because:

we can detect the ACTH and cortisol levels without any test.

If pituitary dysfunction: ACTH down, cortisol down
If adrenal dysfunction: ACTH up, cortisol down,
If hyperpituitarism: ACTH up, cortisol up,
If adrenal hyperfunction: ACTH down, cortisol up.

Anyone can explain why bother using this test? Appreciate it!




  #2

hey this is not a really useful test.. and it is not included in the diagnostic work upof cushings.. but what u have mentioned is just the primary tests.. these values wont help in D/Ds like if its a ectopic ACTH or a pit tumor.. for that u need low and high dose dexa suppression tests and few others that are included in the standard work up..
metyrapone test distinguishes ectopic ACTH from a pit tumor.. but this has a lot of fallacies..
high dose dexa suppression test can differentiate b/w the two and is quite accurate..
i hope i made my point clear..


  #3

thank you, a3112 for your reply.

I agree with everything you said except that"metyrapone test distinguishes ectopic ACTH from a pit tumor..". I don't know how metyrapone test distinguishes these two.




  #4

ok.. i will try to explain this..
metyrapone is 11-b hydroxylase inhibitor.. that is it wil block the reaction 11 deoxy cortisol ----> cortisol.. so cortisol decreases in blood -----> inc ACTH
this is normal response or in case of a pit adenoma..
but in ectopic ACTH prod ----> HPA axis is already suppressed by the large amounts of ACTH in blood.. so no further increase in ACTH in response to metyrapone..
its a bit confusing.. but i tried to make it as simple as possible..
but still this is not useful coz of lots of false results.. i hope this helps..





Bookmark and Share



This thread is closed, so you cannot post a reply.



Login or Register to post messages








show Similar forum topics

help explain the metapyrone test
Uzaq part-time iş
useless LORs vs useful LORs??? for bbb and others
show Related resources

wiki test prep
Pediatrics - Pre Test








Advertise | Support | Premium | Contact