Elevated TSH despite its suppression

[acousmetre]

I had papillary thyroid cancer 4 years ago with local lymph node metastases. I had a complete thyroidectomy and underwent radio iodine therapy. I take a high dose of T4 and normally my TSH level is 0.5 or below. In two recent blood tests my TSH was around 6mcUI/ml, just above and below, and T4 was at the upper limit (1.7ng/dl on last test, lab's max is 1.72). I never miss my T4 and always take it on an empty stomach, waiting another 1/2h before eating.

last ecography of neck was normal

I've also had high DHEA-S, but on last test it was just under the upper limit. I have an adrenal nodule of 1.3cm but it was found to be an adenoma in a adrenal specific MRI. I also had a high normetanephrines recently but normal metanephrine. I take 150mg of bupropion which may explain the elevation.

I will see an endocrinologist tomorrow, but does anyone have any ideas on what might be causing the high TSH?

I'm also having treatment for a recent diagnosis of psoriatic spondyloarthritis. Have a lot of joint and tendon pain.

I have some dizziness too.

Thanks

[greygoose]

Perhaps you aren't converting very well, and your FT3 is low. Or, you could have developed a problem with your pituitary.

[acousmetre in reply to greygoose]

Thanks. T3 was at 71ng/dl. I had it measured only twice before in 2019 and it was much the same. Lab's low limit is 60.

[greygoose in reply to acousmetre]

Is that the Free T3 or the Total T3? It looks like the Total, which is not the right test. And do you have the full range?

[acousmetre in reply to greygoose]

Im pretty sure it's total. Range is from 60 to 181.

[greygoose in reply to acousmetre]

OK, so that's not the right test - you want the FT3 - but it is very low. So, that could be why the TSH has risen. Trouble is, it doesn't give us much idea what your Free T3 is, nor how well you convert.

[helvella]

When you see a test result that doesn't make sense (as in your TSH), it makes sense to consider whether something could be interfering with the test.

For example, antibodies to TSH can attach to TSH, forming what is called macro-TSH. A test which measures how much TSH is in your blood can be fooled by that into giving a higher than expected result.

The usual (and simple) approach is to get re-tested with the samples going to a lab which uses an assay process that is not susceptible to this issue.

(That is just one possibility. There are others but I am not an expert so don't have a list of them to hand. )

[humanbean]

Do you take any supplements which include biotin? Sometimes this may corrupt results for many different tests. It is always suggested that people stop taking biotin in any form during the 3 - 7 days before testing anything. The more biotin is taken the longer the gap that should be left.

To see why please read these links :

healthunlocked.com/thyroidu......

healthunlocked.com/thyroidu...

[acousmetre in reply to humanbean]

Thanks. No, I am not but I am taking sulfasalazine for spondylitis. I just read that this can raise cTSH levels. When I looked further it seems that the c stands for canine but perhaps it affects TSH as well. I'd mentioned the high TSH to my rheumatologist but she didn't draw any connection.

[acousmetre in reply to acousmetre]

or c = capillary

[acousmetre]

I saw my endocrinologist yesterday. Because of the high TSH she suggested increasing my T4 dose even though my last T4 reading was 1.7ng/dl and the lab's maximum is 1.72. She also wouldn't have a bar of T3 testing when I asked. I live in Brazil (although I'm English by birth), so I suppose the approach is different here. I presently take Euthyrox 150, four times a week and Euthyrox 175, three days a week (I am a 57 year old 92Kg male). That dosage schedule is to be inverted. She asked for a further test of T4 and TSH only in 2 months time. I'm already feeling dizzy and I suspect that is going to get worse. I think I will have to pay for a private endocrinologist... She also said that my raised normetanephrine and DHEA-S levels aren't high enough to be considered significant but that I'll need to have yearly imaging done of the adrenal nodule. From my googling, that seems to be a reasonable approach. Whn I asked about the possibility of a pituitary problem that's causing high TSH, she said that tumours of the pituitary are extremely rare. Cheers