Infant Hyperthyroidism

[Curious123]

Has anyone had an infant 👶 (<= 6 months) with hyperthyroidism? What was the diagnosis and how did they proceed to treat it (if they did)? I went hyperthyroid in Jul20 and it was deemed a mild thyroiditis which self resolved (all antibodies negative except for TgAB). Note my Dad has Graves’ disease. Thyroid levels and antibodies normalised and thyroid was within range during pregnancy but now apparently we are both hyperthyroid. For me:

TSH 0.01

FT4 33.0 (9 - 25)

FT3 11.3 (3.5 - 6.5)

Thanks for your guidance and any insight.

[greygoose]

If you had high TgAB then you more than likely have Autoimmune Thyroiditis - aka Hashi's. Hashi's doesn't resolve itself, it's for life. Your immune system slowly destroys your thyroid and you end up hypo. But, before that happens, you can have several 'hyper' swing. Those results you've posted look like a 'hyper' swing rather than hyperthyroidism as in Graves'. It is only temporary and the levels will come down by themselves.

Do you have any other blood test results for your thyroid, from other tests? What about your infant? Has he been tested? Impossible to comment without blood test results, so why do you say you are 'both hyper'?

[Curious123 in reply to greygoose]

We are under a paediatrician for neutropenia and had some blood tests done in which I saw the high FT3, I just don’t have a copy yet. Our follow up with the doctor who ordered the tests isn’t for another 2 weeks.

[greygoose in reply to Curious123]

Well, high FT3 doesn't automatically mean hyperthyroidism. Be interesting to see the new tests in two weeks.

But, for you, I think you're far more likely to have Hashi's than true hyperthyroidism.

[Curious123 in reply to greygoose]

Past results below. For many years now though my TSH usually sits lower level normal in the range. I’ve also postpartum so that increases the risk of postpartum thyroiditis.

02/10 13*-20/8 31/7-5/8

TSH 0.13 (<0.02) (<0.01) [R: 0.27-4.2]

FT4 15.5 (22.9) (29.8) [R: 10.8-25.5]

FT3 4.9 (7.9) (7.6). [R: 3.1-6.8]

T4 94

TPOAb 11.9 (<9.0)* [R: 0-34]

TgAB. 237 (115)* [R: 0-115]

[greygoose in reply to Curious123]

02/10 13*-20/8 31/7-5/8

Not sure what these numbers are - are they dates?

I take it these are three sets of results? Your first FT4 and FT3 results are rather low. Then they go high. That is a typical Hashi's pattern.

[Curious123 in reply to greygoose]

yes, date ranges, so oldest on right to left being newest. So FT4 started high and dropped while TSH concurrently gradually rose back up from suppresses <0.01.

[greygoose in reply to Curious123]

OK, well, that's how it works. TSH is low when thyroid hormones are high - T4 and T3. When T4/3 rise, the TSH drops.

So, right now, your levels are:

TSH 0.13 (0.27-4.2]

FT4 15.5 (10.8-25.5]

FT3 4.9 (3.1-6.8]

is that correct? So, it looks like you are coming down from a 'hyper's swing, but the TSH hasn't quite caught up with the FT4/3 levels yet. It moves much more slowly than the thyroid hormone levels.

[Curious123 in reply to greygoose]

No, my current levels are in the first post, the others were from the first Hyper swing in 2020. In 2023 I’m on the way up in the current hyper swing. Early June TSH was <0.02 and FT4 was 19 which was top of the range.

[greygoose in reply to Curious123]

OK, well, you get the drift. Levels go up and down, but the high levels are only temporary, unlike Graves' hyperthyroidism where the high levels are permenant unless treated.

Eventually, with Hashi's, you will need thyroid hormone replacement.

[Brightness14]

Sad