What can cause a sudden, severely underactive t... - Thyroid UK

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What can cause a sudden, severely underactive thyroid? TSH 100!


For a while ive been getting lots of dizziness, lethargy, inability to move, issues with my sex drive and some mild disorientation. So I paid for a private blood test, got these results back yesterday. Not been to my GP about it yet although I will make an appointment soon.

6 months ago I had a normal TSH and thyroid function as it was checked in A&E. Just looking for some information on what could cause such a huge, underactive thyroid so quickly?

Also how dangerous is this? I read about a guy dropping into a myxoedema coma after his TSH reached 52! With mine being at 100 I am seriously concerned.

Nearly forgotten, why am I so slim? I eat plenty, train in the gym regularly but I still have issues putting weight on. I'm an otherwise healthy male in his early twenties.

36 Replies

It's not high TSH is dangerous, it's low FT3. And you didn't even have that tested. So, although your TSH is very high, and the other guy's TSH was only half yours, you can't compare yourself to him without knowing what his FT3 was and what your FT3 is.

Having said that, and although I think your probably not in any immediate danger, you should get yourself to the doctor sooner rather than later.

As for being slim, not all hypos are fat! A lot do put on weight, admittedly, but some lose weight, and with some their weight stays the same. There are over 300 known hypo symptoms, but you don't have to have them all to qualify. :)

I'd also think about high prolactin. This could be a pituitary problem indicating a prolactinoma there and also should be checked out. Otherwise some supplements can raise prolactin also, and these hould be given a run over.

Your thyroid is clearly failing. I've noticed that patients with a very high TSH often respond to treatment better than those with a lower TSH and similar symptoms. Your fT4 is low but not dangerously low at the moment. Your should see your doctor in the next few days who can put you on a decent dose of levothyroxine straight away (50 to 100 mcg) and resassess you in a month or so. Also mention the prolactin, I don't know anything about this. Why were you in A&E? And are you taking any supplements etc. that might interfere with your thyroid?

MivoUK in reply to jimh111

Thank you, the prolactin I assume is caused by the very high TSH level? I was in A&E because I kept getting palpitations and chest pain. Some tachycardia reaching around 180bpm too. In A&E then done a range of bloods including thyroid which came back clear. This was around 6 months ago. So either A&E messed up them bloods or the thyroid issue has developed in the last 6 months. Supplements not really, I have taken anabolic steroids in the past but not for about 12 months. And I had my thyroid checked 6 months ago and was clear. I've never taken T3, T4 or anything like that.

jimh111 in reply to MivoUK

OK could be autoimmune hypothryoidism which can cause irratic thyroid secretion until the thyroid packs in. See your doctor and see how you go on levothyroxine. It will take many months to recover from hypothyroidism so let employers etc. know so that they can make allowances.

MivoUK in reply to jimh111

Thanks, you have been really helpful :)

I've done lots of research in my spare time and apparently T3 (Liothyronine) works much quicker for correcting hypothyroidism than Levothyroxine. Is this true? If its true do you think my doctor would agree to monitor me and do bloods ect while I buy my own T3 online? As a regular gym goer I can get easy access to T3, likely for less cost than the Liothyronine prescription from the chemist! I only consider this as I hear doctors wont prescribe T3 due to the huge cost in the UK. I just want to fix this ASAP :)

Also the poster below recommended that I don't go to the gym but due to commitments with my personal trainer Its going to be difficult to avoid. Do you have any information on how dangerous it could be if I continue to workout in this current state? Sorry if you have no idea, just asking as you seem very knowledgeable!

helvellaAdministrator in reply to MivoUK

As I understand, high TSH does not itself cause high prolactin. But high TRH, quite likely due to low thyroid hormone levels, causes both TSH and prolactin to rise.

jimh111 in reply to helvella

Interesting, not something that would normally be recognised but makes perfect sense, low thyroid hormones increases both TRH and TSH. So makes sense to take another look at prolactin when MivoUK's TSH has come down.

trelemorele in reply to jimh111

And you are on again with that myth of "patient with high TSH responding better to treatment".

Any reasons you keep peddling false information?

jimh111 in reply to trelemorele

That's the impression I've got from seeing lots of posts on these forums. It may not happen for everyone but we see a number of patients with high TSH levels, they get put on levothyroxine and we don't hear from them again. I assume they have either recovered or died. Patients who do not get better tend to stick around and make many posts.

Having a high TSH with moderately low fT4 shows that your pituitary is fully responding. Patients with the same fT4 levels and normal or moderately elevated TSH clearly have impaired pituitary function as well as a failing thyroid. If my thyroid is failing I'd much rather have a high TSH.

I don't know of any studies comparing inital TSH / fT4 ratio with long term outcome. My statement 'I've noticed that patients with a very high TSH often respond to treatment better than those with a lower TSH and similar symptoms.' clearly indicates that this is my observation rather than an evidence based statement. It's intended to reassume patients who have scary levels of TSH.

How high was your TSH when before you started thyroid hormone treatment?

trelemorele in reply to jimh111

You're theory is wrong.

A lot of your statements are on par with statements fed to us thyroid patients by stock GPs. And are inaccurate.

People leave this forum or become observers only for quite a few reasons: crowd suggestions what to eat, how to test, what's "allowed", what's "must",'suggestions to follow specific thyroid blogger(s) just to name few. Not because they miraculously become healthy in a matter of weeks from TSH in hundreds on diagnosis.

You should speak from your own thyroid experience (you do not have) and not repeat stock GP slogans based only on your OWN observations.

jimh111 in reply to trelemorele

This is my observation. I was severly hypothyroid for many years, lost my job, as a consequence had to retire on half pension and suffered substantial psychological effects. This is my experience. My observation thatpatients with a high TSH have better outcomes than patients with a low TSH is stating what I have seen on the forums, it doesn't come from doctors (who prefer to treat patients with a high TSH). We clearly disagree and I will leave it there.

trelemorele in reply to jimh111

You do not make any sense and you contradict yourself:

"I was SEVERELY hypothyroid for years..."


"...people with high TSH bounce back quick and well" ?

I'm not sure you have to have a high TSH to be 'severely' hypothyroid. We all know that TSH is a poor indication of how we feel. :)

jimh111 in reply to trelemorele

My TSH was 1.0, my hypothyroidism wasn't a failing thyroid but resistance to thyroid hormone which is much more difficult to treat than a failed thyroid.

trelemorele in reply to jimh111

As stated above - you have no experience and no idea what you're talking people about when you keep peddling "good news high TSH - you'll bounce back in no time".

You have no experience in this matter and I repeat - it is not true.

LAHs in reply to trelemorele

I have always found jimh111 perfectly logical and his observations parallel with my own personal experience. All you can do is look at the data we present here, synthesize an hypothesis and make suggestions which will help most people, (Jimh111’s input has helped me). Trelemorele I have not read any theory from you, you have not put forward any suggestions nor offered any constructive help. It’s always a good idea to get all of your facts together, get them straight and double check your ideas before you shoot your mouth off.

Treepie in reply to jimh111

Well done for not responding in kind to insults.

Until you get your thyroid treated I'd suggest giving the gym a miss, and do some very gentle exercise instead that doesn't stress your body. As greygoose said it is low Free T3 which makes people hypothyroid, and if your body can't supply enough Free T3 for your needs then you will become very ill. Exercise increases your need for Free T3.

Thanks for the information. Unfortunately I can not stop going to the gym. I have a personal trainer and he is paid in advance each month. So every week that I don't train I lose £60, that's £240 a month! What is the worst that could happen if I continue to train? I'm meant to be in the gym tomorrow afternoon for a session.

Nanaedake in reply to MivoUK

Your health is more important than your wallet. Tell your trainer your diagnosis. He/she would be irresponsible to train with you in these circumstances. If insured. It may not cover an adverse event if you've not disclosed your medical condition so the trainer should come to a suitable arrangement with you.

MivoUK in reply to Nanaedake

Alright, thanks. But could you please tell me, worse case scenario, what could actually happen to my health if I did train? I'm just trying to understand what could actually happen.

Laundretta in reply to MivoUK

In my experience, it starts with being ok while exercising, but not able to increase strength and/or stamina. Then you get the above plus feeling wiped out the next day. (Achy like a bad cold is coming on)

Keep going and the achy ness goes on for longer and longer and it takes a couple of weeks to feel like being in the gym again (even though you usually enjoy it) and repeat.

jimh111 in reply to MivoUK

Training whilst hypothroid will not harm you. You may have reduced capacity to train and feel very tired afterwards. I'd keep up your training but listen to your body and don't overdo it, just stay within your limits and the training will help.

It's not so much you run out of thyroid hormone with exercise but the energy, metabolites and tissue repair that thyroid hormone promotes will be reduced. So your ability to sustain exercise will be reduced. You should notice a benefit from levothyroxine after about a week but it will take many months to fully recover.

Whilst your exercise capacity will be reduced an adapted exercise course will help you recover so will in one way give better value for money.

MivoUK in reply to jimh111

Thank you, providing I wont give myself silly odds of developing a ventricular arrhythmia then I will continue to train and push through the workouts :)

Can having such a poor thyroid function change lung function? Because my asthma nurse ran a PFT a few months ago and found my lung function was just 68%. She was concerned and said it was very low. I repeated the test few months later and it had improved to 73% after adjusting inhalers, so still low but better. Could this also be down to thyroid function?

jimh111 in reply to MivoUK

Can't really say. Hypothyroidism can reduce intracellular magnesium levels which tends to constrict smooth muscle. This might possibly reduce your ability to take in air. I'm very unsure about this so just have another lung function test a couple of months after you have been started on levothyroxine. Then let us know!

Yes, being hypo decreases lung and heart function, and may also be why your testosterone is quite low for a young gym bunny.

The worst that could happen is that you could end up in a coma. Tell your trainer and ask him to devise a new workout plan to take account of your health.

SlowDragonAdministrator in reply to MivoUK

Your TSH is extremely high

Your long term health is definitely at risk

You need to see a GP this week for prescription for Levothyroxine urgently

Have you recently given up smoking by any chance? This can dramatically raise TSH in someone with underlying Hashimoto's (autoimmune thyroid disease)

You could collapse, heart palpitations are due to heart being starved of essential hormones

Having had TSH of 75 upwards over 30 years ago, I'm surprised your body is allowing you to train at all. My muscles, heart, etc would have caused me far too much pain to continue with any exercise.

MivoUK in reply to marigold22

Very interesting. I can definitely train, but my body is highly adapted to exercise. I've weight lifted since a child so possibly that helps? The only time I feel like I have energy is for the first 10 minutes or so in the gym. Then my energy quickly falls. By the end of the workout I usually walk home extremely slowly and not move off the couch for the rest of the day. E.g I workout at 10.30am until 11.30am, get home around 12 and not move off the couch for the rest of the day. Sure it drains me out for the day but I feel like that bit of exercise is the only thing that keeps me remotely sane.

MaisieGray in reply to MivoUK

MivoUK I think you've just answered your own question as to what happens if you exercise hard ......... I can't speak from personal experience, but I would have thought that being drained and unable to move off the couch for the rest of the day is not a normal healthy response in someone that is a regular life-long gym goer who is highly adapted to exercise.

I used to be a bodybuilder before becoming hypo - it gets worse if you aren't treated and try to carry on - you just feel wiped out all the time. I started having dizzy spells and passing out at work. My hypo came on fairly suddenly after I'd done several shows quite close together. I think I just wiped out my adrenals completely with the hard training and dieting.

Forgot to say it would be a good idea to try a magnesium supplement. Magnesium helps with lung function, is good for the heart and helps improve sleep quality. Avoid magnesium oxide or hydroxide, they are useless. I use magnesium citrate although other patients can recommend different forms.

That high prolactin suggests a pituitary problem (a prolactinoma) which would be enough to cause all your symptoms either directly or by compression of nearby tissue.

This document pituitary.org.uk/informatio... describes causes of high prolactin levels. Note that hypothyroidism is a cause. It is most likely your elevated prolactin arises from your hypothyroidism, prolactinomas are rare.

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