How relevant is TSH when you have had a total thyroidectomy?

[Cavapoochonowner]

Hello everyone, Is TSH relevant at all if you have no thyroid?For someone on levothyroxine only are T4 and T3 the measure of optimum dose.Thankyou.

[pennyannie]

Hey there :

In my humble opinion especially if with Graves Disease the TSH is a very unreliable measure of anything and a pointless measure seen in isolation.

It is imperative that you are dosed and monitored on your T3 and T4 being balanced within the ranges at around a 1/4 ratio and symptoms relieved.

If with Graves you will likely feel improved on higher levels of T3 as your body has been tolerating and adjusted itself to function on high T3 and T4 levels than say perhaps somebody who has never experienced hyperthyroidism.

Tired Thyroid - from hyper to hypo - healing - breaking the TSH rule by Barbara S Lougheed :

Elaine Moore - Graves Disease - elaine-moore.com search TSH :

My all time go for all and everybody - Your Thyroid and How to Keep It Healthy - written by a doctor Barry Durrant-Peatfield to empower patients to self advocate and get better thyroid health treatment and the cause and effect of when your thyroid levels are non optimal.

All books available through Thyroid UK - thyroiduk.org

[Cavapoochonowner in reply to pennyannie]

Thankyou for you very informative reply.This will help me going forward with any blood tests I have.

[tattybogle]

TSH has a "feed-forward" role ....part of that is to give a message to the thyroid to ask it to make more, or less T4/T3 ... and obviously with no thyroid present , that part of its role is completely redundant.

But the "feed-forward" role of TSH ALSO affects the deiodinases . ( responsible for speeding up and slowing down the conversion of T4 to T3 (and T4 to Reverse T3 ,and T3 to T2 )... this aspect is still relevant even with no thyroid ,as this conversion happens all over the body .

TSH also has a "feed-back" role ... sensors in the hypothalamus and pituitary respond to blood levels of T4 and T3 and decide how much TSH to produce ,..... this "feed-back" role still functions even without a thyroid (the pituitary and hypothalamus don't know that the thyroid isn't there anymore , and they don't know the T4 is now coming from a tablet) , and so changes in TSH level can still be used as PART of assessment of dose ~ in conjunction with looking at fT4 and fT3 levels.

But Dr's looking at TSH in patients with no thyroid do need to understand that the TSH level relative to the fT4/ fT3 levels will now be a bit 'shifted' from what it was before they were taking Levo .... to some extent this happens to all patients taking Levo, even if they still have some residual thyroid , but the shift is easier to prove and explain when patients have no thyroid at all.

Vague explanation (sort of ~so don't quote me ..ask diogenes lol) This shift occurs because the ratio of T4 to T3 on Levo is higher than it was in health , and the PITUITARY and HYPOTHALAMUS interpret this combination of T4/T3 levels a bit differently than they did before...... AND because without any T3 being produced 'direct from the thyroid' , we have to take "more" T4 to get adequate levels of T3 to 'satisfy' them , and this "extra" T4 leads to the TSH reading a bit lower than it did before ... kinda thing ?

Also, if the thyroidectomy was done following GRAVES hyperthyroidism , the high T4 /T3 levels from that period can also shift the TSH down bit ,and this effect (called Hysteresis) can take a long time before TSH reading returns to previous levels (months) ,and it may not EVER go back to quite where it was before.. so in patients who had hyperthyroidism which supressed their TSH , their TSH may stay inappropriately supressed for months, and if Doctors do not understand all this fully, and still try to interpret TSH of a thyroidectomised patient in the same way it was interpreted in health , they will misunderstand what it is telling them .

So TSH IS still relevant , but on Levo (and especially without a thyroid , or following hyperthyroidism , or overmedication ) , the correct interpretation of what it means has changed a bit.

[Cavapoochonowner in reply to tattybogle]

Thankyou very much for your quick response.Your explanation has cleared up some points I didn't quite understand.This will help me when I have future blood tests.

[Batty1]

Well to Doctors its the King of all thyroid testing no matter if you have or don’t have a thyroid.

[Cavapoochonowner]

Yes I have seen that on here.I haven't had testing done by my GP yet since my thyroidectomy.I have had 2 lots done by ENT as they have been waiting for my parathyroids to recover(it looks like they finally have).They have tested T4 (no mention of TSH).I just wanted to get a bit of info for when they do test.I have already decided I am going to do at least 3 private checks a year myself, as it costs under £30 to test T4, T3 and TSH.I think that is doable for most budgets.