Advice on lab results - zero TSH?

[tesscoulson]

Was hypo after birth of my daughter nine years ago. Was given thyroxine but levels settled down after year or so.

Sep 2011 not feeling quite right, doctor did tests, then Nov2012 saw endo who now diagnosed Graves and recommended RAI which I declined.

Generally feeling not too bad since but visiting endo again in two days time as have slightly enlarged thyroid which I can feel when swallowing.

Have had four blood tests in recent years, results as follows:

Sep2011
TSH <0.01 (range 0.35-4.5)
Free T3 8.6 (range 3.9-6.8)
Free T4 23.7 (range 11.0-24.0)

Nov2012
TSH <0.01 (range 0.35-4.5)
Free T3 8.4 (range 3.9-6.8)
Free T4 22.2 (range 11.0-24.0)

Feb2013
TSH <0.01 (range 0.35-4.5)
Free T3 7.4 (range 3.9-6.8)
Free T4 21.2 (range 11.0-24.0)

Mar2014
TSH <0.01 (range 0.35-4.5)
Free T3 5.6 (range 3.9-6.8)
FreeT4 16.3 (range 11.0-24.0)

T3 & T4 not really out of line but continual non-existent TSH baffles me.

Really grateful to hear from anyone with ideas about what might be going on.

Thanks

[goolarra]

Yes, TSI and TRab (TSH receptor antibodies) are similar tests.

I'm glad to hear he's ordered more tests and is following up appropriately.  

[tesscoulson]

Hi there

Sorry not to reply sooner.

Endo appt went pretty well and I feel a bit less anxious about it now.

He confirmed I had had (and still had) Graves. My levels seem to be improving but he also felt that I was still rather hyper as my TSH was nil.

He found thyroid somewhat enlarged but no noticeable lumps or nodules. Said that gradual general enlargement was a result of Graves and was usually irreversible.

He has arranged for me to have another set of bloods including test for T3, T4, TSH and TSH antibody (is this what is called TSI in US?) and also an ultrasound on the thyroid.

This will take a while to arrange and then I go back to see him in 8 weeks.

Thanks for your support and advice

T

[goolarra]

Anxious to hear how it went...

[tesscoulson]

Thanks for all your comments.

I now have much better idea of what has been going on.

Seeing endo tomorrow, so hope to get sensible advice from them - not seen them before.

At very least I need TSI test, it seems

T

[goolarra]

TSI is the antibody that, when elevated, indicates Graves' disease.  TSI is used to diagnose Graves' and is monitored regularly.  If it goes down, it can indicate that the disease is in remission.

Your FT3 and FT4 levels have dropped significantly in the past year, so I'm sure that's why you're feeling better.

The TSI antibody attaches to TSH receptors on the thyroid and stimulates the thyroid to produce hormones.  When you have Graves', the antibodies do TSH's work for it...actually they overdo it.  The thyroid is no longer under pituitary control.  TSI just indiscriminately stimulates the thyroid to produce hormone.

Your pituitary checks your FT3 and FT4 levels and decides if there is not enough thyroid hormone available.  If there's enough, it does nothing.  If there's too little, it puts out TSH as a messenger to the thyroid to get to work.  So, if there is no pituitary issue, TSH isn't going to go up until your pituitary thinks levels are too low.  If TSI is still stimulating your thyroid sufficiently to keep your pituitary happy, TSH isn't going to go up.

If TPOab was positive, then you probably have Hashi's in addition to Graves'.  I know it sounds like an oxymoron, but it is possible to have both.  However, a "weak" positive doesn't always indicate Hashi's, and Graves' can inflate TPOab as well.

[tesscoulson]

Yes, I did feel hyper in 2011/12 - palpitations, anxiety, etc. but have been feeling generally better recently, thanks. Still sleep poorly though.

Not on any meds now, nor was I back in 2011/12

It feels as though things are settling down now and I would not be concerned except for the enlarged thyroid gland I now seem to have.

I understand what you say about low/zero TSH being because pituary is not calling for thyroid production. But not sure why was all this T3 and T4 being produced if there was no TSH? And why if my latest T3 and T4 are back within range is there still zero TSH - should it not start to go up just a bit?

I don't think I have ever had my TSI tested. What does this test indicate?

I did have TPO antibody tested in the March 2014 and the result was Positive, but no number given.

Sorry to be so confused. And thanks for your input goolarra. BTW I am female, 45.

T

[goolarra]

When your FT3 and/or FT4 are too high, your pituitary doesn't put out TSH.  It only puts out TSH when it wants your thyroid to produce more hormone.

Has your TSI (thyroid stimulating immunoglobulin) been being tested regularly?

Actually, from 2011-13, your FT3 and FT4 really were out of line.  Most of us would feel very hyper that high in the range or over range, especially over range on FT3.  Were you feeling hyper?  Are you on meds?

However, there is a very significant change this year.  Your 2014 FT4 is only 41% of range, and that's actually getting into hypo territory for many of us.  However, your FT3 is still good at 59% of range.  It is, though, a very big change from where you were for the three years prior.

How are you feeling now?