Thyroid UK

Hyperthyroid or maybe hypo?

Hi everyone,

Am reposting this with a more suitable title as has been suggested - hope that's OK.

I've been having a bunch of medical issues for the past 10 months since having a pretty bad bout of sciatica. Since then, I've been dealing with widespread twitching (diagnosed by a neuro after an EMG as benign fasciculations), general anxiety (am starting CBT shortly) and just feeling really run-down (exhausted and weak). My leg muscles have been frequently tight too, and perhaps because of this, my knees often feel numb, sore or "heavy".

On my thyroid issues, I saw a GP on 21 May regarding the twitching and he ordered a bunch of blood tests which came back with these results among others:

TSH: 0.445 (range 0.65-3.7)

Free T4: 16.2 (8.8-14.4)

B12 serum: 388 (145-637)

Calcium serum: 2.47 (2.09-2.46)

Potassium serum: 4.1 (3.6-5.0)

I only got the results a month later, and the GP (a different one) noticed the slightly high T4 levels and ordered another blood test. The results of those (taken 18 June) were:

TSH: 0.599

Free T4: 14.6

TSH Receptor Antibodies: 0.5 (range 0.0-1.5 IU/L). Specimen is haemolysed.

Based on these results, a third GP started me on 5mg Carbimazole per day which I've been taking for about 10 days, but since then, I've felt as tired/foggy with difficulty falling/staying asleep, if not more so. And I don't know if it's coincidence, but I've started feeling a dumb ache/numbness in my left thumb, more tremors in my fingers (especially the left thumb), some general achiness, weakness and pins and needles in my body since I started the Carbimazole. And I've been feeling chills and especially cold in the office today.

What bewilders me is the extent to which my TSH and T4 are out of range - so much less than what I read here and on other forums (in fact my second test results seem almost normal based on the ranges?) Should I really be on carbi or might taking it for just 10 days already have pushed me into the hypo zone (some of my more recent symptoms seem to be the ones more commonly experienced with hypo?) I'm thinking of stopping the Carbi for a few days and monitoring if some of the new symptoms subside, and going back to the GP in the next few days to see what he thinks and maybe get referred to an endo (as Flowers007 has suggested, I'll also ask to be tested for antibodies, B12, Ferritin and Folate).

Alternatively, might my symptoms might be an adverse reaction to Carbi (if so, might they get better over time?) Or are they more likely to be symptoms of high T4 that will take time to resolve as I continue on Carbi (I've read that effects from ATDs only show up after a few weeks)?


10 Replies

I am sure that someone more expert than me will be able to give some advice.

However - do your blood tests results say what the measurement units that have been used for the T4 and TSH? When I have had blood tests done the reference ranges are:

Free T4 10.0 - 22.0 pmol/L

TSH 0.3 - 4.5 mIU/L

So the top range of your T4 range seems very low, but then all labs vary I guess. As someone who has hypothyroidism I have always felt best when my FT4 was around 16 - 18 pmol/L.

Have you seen an endocrinologist regarding the diagnosis of Hyperthyroidism? Do you have many symptoms of hyperthyroidism?:

Given that your last lot bloods are only slightly out of range, one would hope that the suggestion of treatment would be confirmed by a lot of clinical symptoms of hyperthyroidism too.

The fatigue, chills and feeling cold you have been experiencing do sound like hypo symptoms.

Given that your Calcium is also slightly high has anyone suggested Hyperparathyroidism? It is quite rare and a lot of GPs don't have experience of treating it. So it might be worth checking out the symptoms of Hyperparathyroidism, which can make you fell very rough and cause muscle problems and anxiety. A couple of very good websites are:

Magnesium deficiency, which is apparently very common can also cause similar sounding problems, with muscles and fatigue.

There is a very informative article here:

and a Facebook group reputed to be good (although I am not a member, yet):

Reading about benign fasciculation, Magnesium deficiency is mentioned as a possible cause:

I hope this helps a little xx

P. S. Have you ever been bitten by a tick? (Lyme disease? also mentioned as a cause of BF)

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Wow Sassicat thanks - that's a lot of useful info!

The units for my TSH and FT4 labs are MU/L and PMOL/L respectively. For what it's worth, I am in Singapore, so maybe the ranges depend on ethnicity in addition to the lab techniques? But yes I have read that a good point in the range to target is the 75% mark.

Re symptoms - I seem to be having a mix of hypo and hyper symptoms. The ones that seem to be more commonly associated with hyper are tremors, anxiety and insomnia, along with fatigue, weakness and aches but these seem to present in both hyper and hypo patients?

Thanks for pointing out hyperparathyroidism (ugh, like I needed more possibilities to worry about :() I'll definitely read those sites that you mentioned. And yes, I think it's high time for me to head back to the GP and ask for an endo referral. I fear that it will be a long wait though!


Oh and on Lyme - yes it's something that's been in the back of my mind too. Seems unlikely that it might be a cause in this part of the world, but I was in the US on vacation a few weeks ago - gah!


So the units seem the same!? I wonder why the reference range is so low? Perhaps it is an ethnicity thing. Are you European or a native Singaporean (if you don't mind me asking) If you are European then your needs might be different?

I have blood results from 3 different labs There reference ranges are:

Free T4 - 10.0 - 22.0 pmol/L

Free T4 - 12.0 - 22.0 pmol/L

Free T4 - 9.0 - 26.0 pmol/L (NHS GP)

There are blood test that can be done to rule out Hyperparathyroidism. I suspected it but all my results were well in the normal range.

Have you had your Vit D levels checked (although you probably get enough sun in Singapore for that not to be an issue?)

With Lyme apparently the tick larvae are so tiny (the size of a poppy seed) that you don't always know you've been bitten, and 25% - 30% of people affected don't get the classic bull's eye rash. I only mention as an alternative doctor I have just seen thinks I have it, but I have no recollection of a tick bite. It's the sort of thing that stays with you.

I came across this:

Good Luck xx

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I'm a native Singaporean, so logically I ought to "belong to" those ranges. Vit D - nope, I've not had that checked (I suspect they rarely do so here) but I'll probably ask at my next blood test. That said I have been taking 1000 IU daily for the past few weeks.

I will ask about parathyroid hormones too, maybe when I get set up to see the endo - thanks again for the tip. And about Lyme, it sounds like there's only one lab (in the US - Igenex or something?) that carries out credible testing. I'm not sure about the UK, but I read about a German lady's struggle getting diagnosed and treated for Lyme in Singapore and umm, it didn't inspire much confidence...


Inkoherent, Carbimazole works quickly and can certainly have made you hypo within 10 days if the dose is too high or you don't need it.

Your low antibodies rule out Graves disease which is a common cause of hyperthyroidism. I'm not sure the diagnosis of hyperthyroidism is right. Your TSH is in the low-normal range, one would expect to see it suppressed <0.03 in hyperthyroidism, and FT4 is only slightly elevated above range.

Ask for thyroid peroxidase and thyroglobulin antibodies to be tested. I suspect autoimmune thyroid disease (Hashimoto's) which can cause transient hyperthyroidism in the early stages as thyroid cells are killed off and dump hormone into the blood stream. As the disease progresses the patient becomes hypothyroid.

Carbimazole has quite a short half life so stopping it will mean it is out of your system in a few days and your hypo symptoms should improve.

1 like

Thanks! Yes, like I mentioned in my original post, one thing that doesn't seem right is that my TSH levels are nowhere near the zero or 0.01 levels that almost everyone diagnosed with hyper and put on ATDs reports. And wouldn't it be an amazing coincidence for my thumb to start hurting and for me to want to go to bed by 8.30 every night, right after I start on carbi?

OK, I sort of feel better that my hunch seems plausible :)


An update: I've stopped taking my Carbi entirely for about 10 days. I am feeling better in some ways - I no longer feel perpetually sleepy and foggy, am feeling less weak and my tremors might even be improving. However, my fingers and hands still hurt, probably more so than before. It feels like the pain is more in the muscles than the joints, but I can't be certain.

Anyway, I went back to the GP about four days ago and she simply said to stop taking the meds if I felt better doing that, although carbi typically takes a month or two to bring about changes to symptoms. I asked for a bunch of bloods (FT3, FT4, Vits B12 and D, folate, ferritin, magnesium, calcium) but will only get to review the results a month from now. In short, the doctor didn't seem particularly helpful :(

So I'm seeing a private endo (supposedly a good one) next Friday and am hoping that she will be more comprehensive in looking at my case, ordering the right blood tests and treatment etc. I'll also ask for her opinion on whether I should see a rheumatologist.


I notice your calcium level is slightly over range. Your vitamin D supplements will raise your calcium, and it is possible that your vitamin D level is already okay and you don't need to supplement. You really need to get it tested to find out what is happening. One thing you could take which might help is vitamin K2 supplements which help to make calcium go into your bones rather than end up lining your arteries. I am also aware that there is a connection between high calcium levels and hyperparathyroidism, as has already been mentioned above. Until you have had a vitamin D test, and possibly tests for hyperparathyroidism as well, I definitely think you should stop taking vitamin D supplements.


Latest bloods:

FT3: 1.7 (range 1.1-2.6)

Calcium total: 2.44 (2.09-2.46)

Ferritin: 232 (47-452)

Iron serum: 15 (11-32)

TIBC: 57 (44-73)

Transferrin saturation: 26.3% (16.0-55.0)

Folate: 45.2 (>13.4)

B12: 396 (145-637)

Magnesium: 0.87 (0.74-0.97)

Albumin: 49 (40-51)

Vit D, FT4, TSH and antibodies weren't taken, argh. Anyway, I'm seeing a private endo on Monday to get a second opinion on whether I should resume the carbi (the GP I saw yesterday feels strongly that I should not have stopped) and will ask the endo to run another set of bloods, including antibodies and parathyroid.

I'm also being tested for RA since the GP doesn't think that thyroid issues or meds are causing the hand/finger pains - will probably get the results in a week or so. This is getting really draining and depressing, I actually cried last night :(


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