This is a question for humanbean (and obviously everyone else) who, in another thread wrote: 'Just wanted to point out that someone taking thyroid hormones won't top up what their thyroid is producing. The added thyroid hormones replace what the thyroid produces by itself.' I am confused by this. I'll explain why.
In December my daughter had a hemi-thyroidectomy (cancer). The surgeon is very keen to totally suppress TSH as he says it will probably cause cancer to recur. She has declined for now so that she can see how the remaining thyroid is working. This was the whole point of not having TT. Her FT3 and FT4 are lowish (FT4 is 14 (9-23) and FT3 is 4.0 (3.1-6.8) but both are within range and have improved slightly since surgery in early December. However, her recent blood test showed her TSH has risen to 5.2 (range is 0.3-4.2). It was 2.4 at the end of December, two weeks after surgery. We thought that we'd monitor for about six months to see how the hormones balance up, and if the FT3 and 4 stay low, or the TSH high, then maybe ask for a low dose of thyroxine. I thought the thyroxine would supplement what her body is producing and also bring down TSH slightly but not to 0 as the surgeon would like (a higher dose would be needed). Your words at the top of this post suggest I have totally misunderstood the process. Any ideas, thoughts really appreciated.
Written by
swanndhome
To view profiles and participate in discussions please or .
If thyroid levels are low, vitamin levels tend to drop
Low vitamin levels tend to lower TSH
So it’s important to get FULL thyroid and vitamins tested
For full Thyroid evaluation your daughter needs TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested. Also EXTREMELY important to test vitamin D, folate, ferritin and B12
Ask GP to test vitamin levels or test privately
Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and before eating or drinking anything other than water .
This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip)
Private tests are available as NHS currently rarely tests Ft3 or thyroid antibodies or all relevant vitamins
Yes, once start on levothyroxine, this will replace your own thyroid output. So it’s important to get on high enough dose levothyroxine to replace missing thyroid hormones
Different cancers require different degrees of TSH suppression for different lengths of time so you should take the surgeon’s advice. Your daughter could take some levothyroxine, perhaps enough to keep her TSH around 0.1 and see how she does. In the unlikely event this gave problems she could back off a little. If TSH goes much lower i5 might be difficult to come off thyroid hormone tablets because when the TSH is kept very low for a long time her pituitary can become down-regulated, it no longer produces sufficient TSH to fully stimulate the thyroid.
TSH will stimulate whatever functional capacity remains in any thyroid gland, other things permitting. Adding t4 and or t3 will reduce TSH and at some point this could be kept low enough to stop stimulation of the thyroid gland, until that point it will likely keep producing t3 & t4. Why keep it going at all if you have to add even a partial replacement, particularly if there’s a risk of initiating cancer cell growth?
It is not a case of just topping up thyroid hormones because any added thyroxine can influence what your daughter is already producing herself from the remaining thyroid gland.
The low level of thyroid hormones has resulted in a raise in TSH. You are considering adding a small amount of thyroxine to top-up hormones, and endo wants TSH lowered to reduce thyroid activity. However, upon sensing the sudden addition of any T4 the pituitary will often reduce TSH by an inproportionate amount to the T4 that has been introduced. Some people refer to this as the pituitary becoming suddenly lazy.
Any amount of TSH reduction will influence her own production of thyroid hormone that is already low and may reduce it further. And another consideration would be any reduction in TSH would reduce the level of conversion of own and any added T4 to T3, and it is the T3 that we need for good immunity and continued well-being.
It is so multifactorial there is no clear answer but I have to agree with jimh111 that you should take the surgeon’s advice. Have you considered adding a T4/T3 combo? As I understand it the NHS can use T3 for some cancer TSH suppression.
Thanks for all insights. The whole point of having the HT was to try to avoid medication. Half the thryoid was healthy so taking thyroxine sort of undoes the whole decision behind that op. I still don't understand how a small amount of thyroxine, say 25-50mcg, will not simply supplement the hormones your gland is producing and instead seems to stop it producing anything at all. How does that work? I thought that lots of hypo people supplemented a low functioning thyroid with a small amount of thyroxine. Is that then not the case?
almost always when on levothyroxine dose is likely to eventually be roughly full replacement dose, even if we start at lower dose
As soon as anyone starts to take levothyroxine the feed back mechanism of TSH is broken
As an example....if, when perfectly healthy, your own thyroid made the equivalent of 125mcg levothyroxine....and this metabolism is controlled by pituitary sending messages - TSH (Thyroid stimulating hormone)
As thyroid starts to fail (usually due to autoimmune thyroid disease) ....but in your daughters case....now only half a thyroid......so might get diagnosed when the thyroid has reduced output to roughly equivalent of 75mcg levothyroxine
Pituitary has noticed there’s a drop in thyroid hormones in the blood....(that’s Ft4 and, most importantly, the active hormone Ft3) ....so to try to make more thyroid hormone ...pituitary sends out stronger message to thyroid - TSH rises up
When GP starts patient on 50mcg ....initially they feel a bit better ....as then have 75mcg from own thyroid output and 50mcg levothyroxine
But ....levothyroxine doesn’t “top up” patients thyroid output.....well it does very briefly....but the pituitary very soon “sees” the levothyroxine in the blood....and TSH starts to drop
So at the end of week 6 ....TSH has dropped a lot. The thyroid not being asked to work so hard ....takes a rest ....has a holiday
So at this point patient is now only mainly using the 50mcg levothyroxine....which is actually a dose reduction down from managing on 75mcg from just thyroid before starting on levothyroxine
So patient starts to feel worse .....and is ready for next 25mcg dose increase in levothyroxine
Dose increases repeat until on necessary final dose, usually roughly 1.6mcg per kilo of patients weight
Modern thinking ....and New NICE guidelines suggests it might actually be better to start on higher dose .....but many medics just don’t read guidelines ....and many patients can’t tolerate starting on more than 50mcg and need to increase slowly
Consider starting levothyroxine at a dosage of 1.6 micrograms per kilogram of body weight per day (rounded to the nearest 25 micrograms) for adults under 65 with primary hypothyroidism and no history of cardiovascular disease.
Traditionally we have tended to start patients on a low dose of levothyroxine and titrate it up over a period of months. RCT evidence suggests that for the majority of patients this is not necessary and may waste resources.
For patients aged >60y or with ischaemic heart disease, start levothyroxine at 25–50μg daily and titrate up every 3 to 6 weeks as tolerated.
For ALL other patients start at full replacement dose. For most this will equate to 1.6 μg/kg/day (approximately 100μg for a 60kg woman and 125μg for a 75kg man).
If you are starting treatment for subclinical hypothyroidism, this article advises starting at a dose close to the full treatment dose on the basis that it is difficult to assess symptom response unless a therapeutic dose has been trialled.
I was going to explain further but SlowDragon has done an excellent job.
Remember all this is what can happen but not necessarily what will. You are on a forum where people are or have been extremely ill through misconstrued/ill managed thyroid issues .
At least you are now better informed to discuss and make choices with the endo. I wish your daughter well.
I find this a little worrying, what has the surgeon advised and which thyroid cancer is it? Did they explain why suppression is thought to be necessary? I had a partial (for lump) and then total thyroidectomy (for cancer) over 10 years ago and the advice was that suppression will prevent the thyroid from trying to regrow and thus possibly growing cancer cells with it, it will do this if it sees that the thyroid is not coping (TSH level). Standard treatments have over the years led to 90% success rates. The thyroid produces a number of hormones but the standard practice is for Levothyroxine only which replaces only T4 leaving the body to cope without the rest which it does in most circumstances but not always. Also, add the thyroglobulin test which is an indicator of spread and check calcium levels in case of damage to the parathyroid glands. (See advice on vitamins etc) Is she receiving any further treatment? Have a look at Butterfly Thyroid Cancer Trust for specific thyroid cancer advice.
Papillary carcinoma. She is currently recovering from surgery and considering all options. Thanks for the advice and pointer to the BTCT. Despite the surgeon advising TT, RAI and TSH suppression, he also admitted that thyroid cancer treatment is very much a one size fits all and lags behind other cancer therapy. It is also IMO an aggressive treatment and there is a lot of divided opinion around every aspect eg TT or hemi? RAI or not? How much? Dissections? It is because of all the debate that she has not rushed into things and tried to hand on to half her thyroid. PC is not a good cancer to have despite them saying that. Yes, it's slow but there seem to be more recurrences than with other cancers plus removal of a gland you cannot live without, the potential effects of RAI etc. So she is taking her time.
How much TSH needs to be suppressed and how long depends on the individual's cancer, it needs expert assessment (and they can't guarantee to get it right). You can supplement with some levothyroxine and leave the thyroid to produce the rest, the TSH will adjust accordingly. There's a difference between a healthy thyroid (half of it) and a diseased thyroid progressively failing.
Your comment 'removal of a gland you cannot live without' is incorrect (sorry), millions of people have had a thyroid removed and most do fine although some find it hard to fully recover as you will see on the forum.
Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.
Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.
Thyroid hormone resistance
Doc says I'm over-replaced - what do you think?
Base Thyroid Hormone levels - what medication best after thyroidectomy?
What to do when supplements change thyroid levels?
