pheocromocytoma and clonodine suppression test?

[heartracer46]

I had a cat scan and it showed a pheocomocytoma (ordered by my PCP), my question is
the endocrinologist that I went to had me
do a clonodine suppression test? . .Anybody tell me why the cat scan
showing the pheocom- isn't proof enough? What's the purpose
of the suppression test if it already showed up on the cat scan?
I have elevated levels of plasma free metanephrines.
I read that the suppression test is not reliable?
Thanks

[LivingInHope]

Heartracer,  

As a lay person, it seems to me if they already see the  tumor, any further testing would be more for the cause of medical journalling than for your own benefit.  It seems to me they should be ordering surgery to remove the tumor, unless they are unsure of what the radiologist found.

My own story:  I was diagnosed with P.O.T.S. a few years back.  I suspect I have the hyperadrenergic form.  I recently had a clonidine test... however I have seen an article (which is also posted on ncbi nlm nih gov pubmed 19307679 (if interested PM for full address).  It states a conclusion of: "The clonidine suppression test without normetanephrine measurements and the glucagon stimulation test are not sensitive enough to safely exclude phaeochromocytoma in patients with mildly elevated plasma or urine catecholamines."
A number of times, one of the catecholamines or it's inactive metabolite counterparts, normetanephrine or metanephrine, have been above normal range in my own case.  The highest level was norepinephrine at 515 (normal lab reference range went up to 399).  The clonidine test started me out with a slightly high epinephrine # according to labcorp, but otherwise it was considered a normal test by the endocrinologist I was going to.  I'm trying to get to a different endocrinologist now for possible further testing, since I did not get the glucagon test.

But I probably don't have that rare tumor, but rather part of this dysautonomia problem I have.

[BhumikaMD]

Hi,

The website works fine on my computer, but here is it again for your reference: http://www.pheochromocytoma.org/sys-tmpl/frequentquestions/

Hope this helps now.

Best regards

[heartracer46]

I just read something on a website. I had coffee, cigarettes, took my torpol XL,
(have hypothyroidism) took my levothyroxine, . . I read you should avoid these
4 hours before the plasma free metanephrine test. I ASKED them if I should
avoid eliminate anything including meds before the "blood work" plasma free
metanehprine test and they said NO. . ...Could any of these interfere with
my test results for that test? . . Also I asked if I should avoid anything, meds,
coffee, etc before the clonodine suppression test and they also told me
NO.
I'm so confused.
Thank you Kindd. . that website came up in my URL but the one that BhumikaMD
gave me , I still can't get that one.
Thanks for listening to my rambling.

[heartracer46]

Thank you also for the reply. . What is a MBIG?
Btw, my symptoms are similar to POTS or sinus tachacardyia (spelling?)
trembling, sweating,. . .most of them triggered by going from laying to standing
(to be more specific) from sleeping all nite to staniding, don't have the same
symptoms when napping. I had a holter moniter test which showed really nothing.
Btw, I also have tachacardyia and have for 23 years. .. I take toprol XL.
My old doc said I had hypoglycemia . . . . wasn't happy with that,
got a second opinion, switched doc's and he tested me for everything
under the sun and he told me (I've been on toprol XL for awhile) ,  .. .he thinks
that the toprol XL is the culprit, even thought the cat scan showed
a phemomocytoma. I know that phemo's are found incidentely and most
don't cause problems. but he said "No' you dont have hypoglycemia,
he said the toprol XL would cause hypoglycemic like symtpoms just
like the elevated plasma free metanephrines. . . I'm so confused with
all this new stuff. I am emphatic that these heart racing spells, trembling,e tc
are not panic attacks. I take xanax 4 x a day for  a vestibular problem
and have for 12 years. I don't get panic attacks. Is the Toprol XL interferring
with the elevated plasma free metanephrine test (blood test that is)
the 24 hour urine metanephrine test was negative, didn't show anything.
I don't have high blood pressure. My blood pressure is too low. .
However I think I fall under the category of the symptoms of POTS
go from laying to standing and the blood runs from my head to my feet
and I get lightheaded (but I've always had this even in childhood)
but just in the last year, then my heart starts racing upon standing,
like pulse goes above 160 (that's not normal for me being on toprol XL)
I hope this makes sense. I'm just confused. I did have panic attacks
when I didn't take xanax , I know what they are, these are not
"emotional" related. I am not a nervous person. Something is really
"physical" going on w/ my body.
These heart racing attacks are so herendous , they scare me into almost
going to the ER, and to be honest, the WORST attacks are (hours) after drinking
beer? . . Is there a correlation here? . Let me rephrase that. .. . I've had
tachacardyia for 23 years, I drank years ago, no problems, didn't drink for
(years) and then social drink now and doesn't matter if it's 1 , 2 or 6 beers,
only on ocassion , not everytime, I wake up 2 or 4am , stand up,
heart starts beating probably 170 or higher (pulse) , something isn't
right here .When I go from laying to standing , (keep in mind, my BP is very low
(in the 90's, always) when the blood runs down to my lower extremeties and
my heart has to beat faster to get the blood back up to my head, is that
causing my blood pressure to go UP?
The endo tested my BP laying down . . .was 100.  . .he had me stand up.
BP was 110 . . Is that significant? . .but when it happens in the middle
of the nite, my heart beats much FASTER then it did in his office.
Any thoughts?
Thanks so much.
sorry so long
I'm just thorough!

[heartracer46]

Thank you for the rely. That website you listed comes up as something
to do with "architecture domain" . .. .
Can you please post the website for phemomocytoma / questions, etc .again?.
I copied and pasted the website and  I don't see anything medical whatsoever
on there. Unless I'm doing something wrong with pasting it in the URL spot?
thank you

[Bhupinder Kaur, MD]

Hello,

It is seen that most, but not all, pheochromocytomas can be localized by computed tomography or magnetic resonance imaging. Pheochromocytomas can have a highly variable presentation, making diagnosis challenging. To think of the tumor represents the crucial initial step, but establishing the diagnosis requires biochemical evidence of excessive catecholamine production and imaging studies to localize the source.

To see whether there is essential hypertension along with, the endocrinologist may have ordered for this test. Catecholamines are suppressed with clonidine in patients with essential hypertension, but not in patients with pheochromocytoma.Also the doctor may be wanting to check whether the findings are consistent with the CT findings.

Recent theories have postulated that Nuclear scans such as MlBG (sensitivity 88% and specificity 89%) help identify the site of catecholamine production in particular when CT (sensitivity 100% and specificity 50%) or MRI imaging fail to locate the lesion or their findings is inconsistent with biochemical evaluation.
http://www.endotext.org/protocols/protocols7/protocolsframe7.htm

So pls talk to your doctor about the option of MIBG.

Hope it helped. Take care and regards.

[BhumikaMD]

Hi,

Pheochromocytoma is a tumor of the adrenal gland which leads to discharge of compounds called catecholamines in the blood which are responsible partly for the sympathetic responses of the body.

All the tests that you have outlined fulfil different functions. While the urine metanephrine test is a high sensitivity test for the diagnosis of Pheochromocytoma, the CT scan is used find the presence or absence of a mass and its size. The Clonidine suppression test is a method to find out the source of the metanephrines and to establish correlation between the size and the tumor characters. The CAT scan is also used in case surgery may be required.

I hope this helped you  a bit. you may also find more information at :http://www.pheochromocytoma.org/sys-tmpl/frequentquestions/

let me know if you may have any other queries.