Why do doctors use TSH and ignore T4?
Ray
blood tests came back with TSH suppressed at .02, T4 5.9 (5.8-14.1)
and FT4 .6 (.6-1.6). Doctor came to conclusion that the TSH is the
important reading, that T4 is unimportant, and I am hyper even though
I have no hyper symptoms but still have some hypo symptoms. A second
doctor agreed.
As I understand TSH is a control hormone and T3 and T4 are the ones
that do the work. An analogy is that TSH is like a thermostat and T3
is the temperature in the room. To find the temperature one can look
at the thermostat and if everything else is working they will know the
temperature. But if for instance the furnace is broken it is better
to measure the temperature.
From my reading I conclude that it is likely that my pituitary is not
working properly because TSH is saying I have enough thyroid hormone
while my T4 is on the low side.
I am trying to understand the thinking of medical practitioners in
hope of getting more enlightened care. From my blood tests what in
their training would lead a doctor to the conclusion they came to? Or
am I wrong in my thinking?
Herman Family
"Ray" <R...@q.com> wrote in message
news:buf9m3tfdb294rcin...@4ax.com...
The general recommendation is to use tsh to dose, rather than the t4 level
because the tsh is indicative of the t3 and t4 levels in most patients.
In your case, you are taking armour, which enhances the t3 level in addition
to the t4 level. Your t3 levels are fine, so the tsh says things are ok.
The t4 level droops a bit for now, because you are converting some t4 to t3,
but armour isn't replacing it all the way. When a patient is taking armour,
the t4 level will typically be low. To avoid excessive doses, you really
have to use only the tsh level.
If you were on a synthetic t4, such as synthroid, levoxyl, levothroid, etc,
then the t4 level would closely correspond to the tsh level.
Bottom line is that the doctors are correct in this case. If you were
taking just t4 and had these tests with full treatment, you would have
another problem.
Michael
Ray
Thank you for your answer, I am trying to get educated. The next
logical question is why is it that the doctors refuse to test for T3
and free T3? It still seems like looking at the control hormone,
rather than the hormone that does the job. Initially the doctor told
me that TSH and T4 were important, but T3 was meaningless.
>In your case, you are taking armour, which enhances the t3 level in addition
>to the t4 level. Your t3 levels are fine, so the tsh says things are ok.
>The t4 level droops a bit for now, because you are converting some t4 to t3,
>but armour isn't replacing it all the way. When a patient is taking armour,
>the t4 level will typically be low. To avoid excessive doses, you really
>have to use only the tsh level.
>
Can a person be overdosed and not have a single symptom of
hyperthyroidism? I have a resting pulse rate of 50, low blood
pressure, cold hands and feet even though I live in the tropics,
throat and neck pain which no one can seem to find the cause. The
throat and neck pain did improve with increasing thyroid medication
but never went away. It is mostly the neck that I am concerned about.
pkmn
here. As I understand things the game is to establish a level of serum
T4 (and T3?) which leads to an asymptomatic state - neither hypo or
hyper thyroid.
What you are saying is that even though a patient is demonstrably low on
T4 it makes no difference because TSH is the only thing that counts
here. In the case of the question at hand, 120 mg of Armour is
delivering 76 mg of T4 and 18 of T3. The blood levels are at the lower
edge of T4. Therefore the state is hypothyroid. And this is confirmed by
the symptoms. It is apparent that increasing the T4 dosage might
increase the serum T4 readings. The TSH loop is broken, or else,
pre-therapy there might not have been clinical manifestation.
I understand that docs like to make easy decisions based only on TSH
when thyroid supplementation is NOT being used. But thereafter, if
supplementation is being employed the goal is to adjust thyroxine levels
also considering symptoms presented. To me this is the major problem:
many docs refuse to look at the whole picture and insist that TSH is the
end all. And this is clearly not so.
Phil
Herman Family
"pkmn" <ne...@ezweddingplanner.com> wrote in message
news:47655ee3$0$10296$815e...@news.qwest.net...
Sorry, it does get confusing. I'll do this one step at a time.
The thyroid produces mostly t4. A bit of t3, but mostly t4. The t4 is long
acting, with a half life of about 8 days.
The t4 is converted to t3 in the liver, muscles, pituitary, and other
organs. T3 is the active form of thyroxin. It lasts only a few hours. T3
production is proportional (more or less) to the T4 level.
Synthroid, levothroid, levoxyl, and such are pure t4. They are synthetic.
The idea with them is to increase the t4 levels until the body has enough to
produce the right amount of t3.
The pituitary produces tsh. It produces more tsh if there is too little T3,
and less tsh if there is too much t3. We call that negative feedback.
The thyroid gland "reads" the tsh level, and either boosts production or
decreases production accordingly. Too high tsh and the thyroid will go into
overdrive. Too low a tsh and it will take it easy for a bit. (more on
this later).
So we have it TSH tells the thyroid to make t4, which is converted to t3,
which tells the pituitary that things are ok, so it can reduce the tsh it
makes.
Now lets look at some problems.
IF the thyroid is too weak, it can't make the t4. The t4 doesn't get
converted to t3, and so the pituitary increases the tsh production.
If the thyroid decides to go nuts and produce lots of t4, then more t3 is
made, and the pituitary drops the tsh production.
With Armour, both t3 and t4 are produced. Sometimes people additionally
take t3 alone. This means that t4 comes only from Armour, but the t3 comes
from both the Armour and the t4. If more t3 is taken, then there are three
sources of t3, not just one. That means that the body must have less t4 in
stock with armour than with synthroid or in normal individuals to maintain
the t3 level.
The net of it is if a patient is on t4 only, then the tsh, t4 and t3 levels
should agree with one another. On armour, the t3 and tsh will agree, but
not the t4. On pure t3, it is possible to have a near zero t4 level but a
normal tsh level. The easiest thing to rely on is the tsh, which is the
body telling itself how it is doing on thryoid levels.
Unfortunately, there is a downside to all this. If t3 is taken orally, then
to avoid hyperthyroidism, t4 intake must be reduced. At that point, the
patient is taking a short term medication. If the t3 were not available for
some reason, it would be only a few days before things went bad. If a
person on t4 only were to fall in the same availability problem, then it
would be a few weeks before they were in the same straits.
Michael
pkmn
say he is hyperthyroid without knowing what the T3 level is and further
with Ray still exhibiting hypo symptoms. My understanding is that you
agree with the docs in this assessment.
One more thing - when you say synthetic T4 do you mean simply
supplemented T4? That is, are synthroid et al. not bio-identical to
thyroid produced T4?
Thanks for taking the time,
Phil
Herman Family
Phil,
Hyper vs hypo is a difficult decision sometimes if you just look at the
symptoms. Both make you feel tired, both may lead to dry skin, hair loss,
etc. Hyper often is a result of overtreated hypo. In any event, it often
gets down to the test to figure it out. In this case, the tsh is one of two
tests to use. If the ft3 is in range, then the arbiter is the tsh. My
guess is that the t3 is on the high end of the range. Note, though that it
only lasts a short time in the system, so the body is getting a "roller
coaster" effect.
Synthetic t4 is bio equivalent to ordinary t4. It may not be identical
in the pill because it must pass through the digestive tract and get
absorbed in the right form. The pill contains sodium levothyroxin. The
sodium is probably ripped off in the stomach and replaced with hydrogen, to
make levothyroxin. Levothyroxin is absobed in the duodenum and the
jejeunum, which are the first two sections of the small intestine. The
pills also contain various dyes, binders, and bulking agents. These may
cause different brands to absorb differently from person to person.
Michael
Alan B. Mac Farlane
wrote on 12/15/07 10:04 PM:
> Why do doctors use TSH and ignore T4?
Thyroid Stimulating Hormone ... effects every cell in the body ... not just
the thyroid gland.
As a hormone, think of it as a global neurotransmitter.
Much like phermones in an ant colony (hold over from ancient body forms this
water bag we live in has used ... it hates to toss things away ... so like
old buttons in a button drawer, they stay put, until activated in other
situations they lie dormant) ... hormones like phermones effect everything.
So it is your master gland the TSH comes out of at the base of the brain
just behind the eyeballs ... it is said to be light sensitive ... so getting
the right kind of sunlight stops Seasonal Affect Disorder. Also a lack of
light, keeps many things broken in the brain until they get the right light.
But that is another matter ... that is likely related.
Anyhow ... if the TSH is zero ... then it has to make a difference in the
thyroid function ... sometimes NOT ... and this is BAD.
Push down the tetter totter, it better move or check the hinge.
Something is broken ... so that is why the TSH is looked at ... it runs
things ... and then see how the thyroid is responding.
Cancerous Thyroid tissue ... wants to make thyroixine .. but because it is
cancerous .. then it makes more cancer to make more thyroixine that it is
not making well. Cancer is much like an MBA ... if Thomas Edison was an MBA
we would all be reading using bigger candles. Cancer works the same way,
making bigger stuff with little results. So you get President Bush. A
distant example that proves the rule.
TSH ... solves the paradox of what is broken in looking at the thyroid.
Why it is broken is settled on later as well as how to go about fixing it as
best as the situation will allow.
Hope this helps.
sumbuddie who cares
:)
pkmn
assay. As far as T3 being short term, since a T3/T4 combo as in Armour
is being used you would mitigate the T3 "roller coaster" because of the
T3 <--- T4 effect; that is, as T3 is metabolized the T4 would buffer it.
This would appear to be an advantage of Armour as well as T3/T4 combo
therapy which so many books/docs seem to recommend.
Phil
Ray
wrote:
It would be reasonable too get a T3 test, but doctors frequently
refuse it because they say it is not necessary. In my case the last
doctor would not do T3 and after ordering a "complete" thyroid panel
(which does not include T3) said he would bet the T4 is sky high. When
the results came back he said T4 results do not matter only TSH. It
still makes no sense to me why TSH would be more reliable in giving
the state of the thyroid hormones than using T3 and T4 tests to
measure the hormones direct. If the hormones don't agree with the
control hormone then it would seem to me that there is a problem in
the control system. Doctors have told me that my thyroid problem is
probably trouble either in the adrenal or pituitary but can't find it.
While hypo and hyper may share some common symptoms in general they
are polar opposites. Of the people who I know who slowly cycle
through the two states tell me they have no trouble in knowing which
state they are in. It seems to me that Michael is ignoring some of my
questions, it is like talking to a doctor. Phil you seem to be a more
reasonable questioner.
I understand that in the past thyroid medication was misused by
doctors as a weight loss drug and that may be part of the reason it is
now difficult to get reasonable treatment. Is this the only reason
why it is difficult to find a doctor who will listen and try to find
what is wrong and get proper treatment.
Ray
Herman Family
Yes, it would be a good idea to get a full thyroid panel once in a while.
The t3 will more than likely be on the high side, and the tsh on the low
side. My thought is that until the tsh is shown to be working properly, the
entire thyroid panel should be run. In most patients, the tsh is working
properly. A lot of times, people feel so good for a couple hours on the t3
that they want to stay on it. People aren't great at objectively or
subjectively measuring long term changes accurately. The blood tests make a
good objective tool.
Increasing armour while decreasing cytomel (t3) would be a good idea. That
will take out some of the variations throughout the day. It will also let
the body do more of the conversion for itself. It is made to do that.
Simply taking t4 is actually a pretty decent therapy also. The body makes
the t3 from the t4. Some folks prefer the armour, others do well on the
synthetic.
Michael
deT notsuH
of its range! Ok, already been discussed....about the T3 business....
but what I did NOT see discussed is when you took the last dose in relation
to when you visited the vampires for the blood draw? It is best to
wait until AFTER the blood draw to take your thyroid meds for that day.
If you take them BEFORE the blood draw, then TSH will be suppressed most
likely. For people taking just T4, because of the total body burden
of T4, the T4 results are not that much affected. This is not true
of those taking Armour or T3 drugs as the half-life of T3 makes it
much more variable during the day....making it difficult to get a
reliable test result that means dooodly squat.
--
deT notsuH bass-ackwards ude.hcimu@pcird
A good doctor can add ten years to your life, but eight of
those years are spent in his waiting room.