Small infection temporarily followed by low thyroid function. Can it happen again?

[123454321]

After typing all of this out I realized it's way too much text for such a small issue but hopefully you understand. I'm really sorry lol.

So 3 months ago i had a pilonidal cyst that got infected and made me experience a lot of tiredness and the occasional slight fever. During this time I also felt like something was wrong with my brain. Brain fog for lack of a better word. I treated the cyst and although the small hole is still there it stopped being infected.

Following this I felt really tired and slow in my mind so I went to the doctor and got some blood testes done. This was over a month ago and although I felt really bad, the tests only showed a slightly elevated TSH-level of 3.90 (with a reference range of 0.58-3.59). She didn't think much of this but just to be sure she ordered another test of only my TSH and T4 levels. I did the test about 1 week after the first one and got the following results:

free T4 12 pmol/L range 10-17

S-TSH 4.68 mE/L range 0.58-3.59

She basically stopped caring about my complaints following this since my t4 was within the reference range. I suspected there was something wrong with my thyroid anyways given that my tsh had gone up and was slightly higher than normal.

I went to a private lab a few weeks later (2 weeks ago) that charges you for any blood test that you wish to have done and got the following :

free T3 5.1 range 3.1-6.8

free T4 19.0 range 12-22

TSH 2.8 range 0.3-4.2 So obviously my tsh and t4 improved over this period suggesting they weren't normal at the beginning of my tests.

So basically I'm here to find out what the hell this means. I had some sort of localized infection that lead to extreme tiredness and a feverish state and then my thyroid hormones took a weird dip but are now recovering. Will this happen again and is this something people are familiar with? I can't find much "popular science" about this connection and I'm not educated enough to completely research this field with the help of scientific papers and stuff.

I still feel a massive amount of brain fog and if anyone is familiar with this reaction test humanbenchmark.com/tests/reactiontime i used to score in the 170-180s and now I get about 250. I'm in a constant state of confusion and my reading comprehension and ESPECIALLY my reading speed feel like when I was 12 years old.

I realize this is a lot of unnecessary text for such a minor issue but I'm hoping someone can tell me how infections affect thyroid function and hopefully tell me what happened and if I can ever return to normal.

[Nanaedake]

You need to get a blood test for thyroid antibodies TPO and TgBa otherwise known as Thyroid Peroxidase and Thyroglobulin. If you have thyroid antibodies your thyroid levels can fluctuate due to the activity of antibodies. So testing for antibodies will confirm whether you have autoimmune thyroid disease otherwise known as Hashimotos.

If you do not have thyroid antibodies then you might conclude it was caused by an infection. Also, taking thyroid blood tests at different times of the day can cause a variation in results so always take thyroid blood tests early morning and fasting.

[123454321 in reply to Nanaedake]

TY for the quick reply. I always took the tests early and I don't eat breakfast anyway. The last blood test I mentioned was basically a package that included TPO antibodies but not the second one you mentioned. Not sure how to interpret the result but it says Result<5.0 (normal) and the reference is <34. This was from the test where I got quite a high T4 result however. Not sure how much these antibodies would fluctuate in a person with TPO-ab issues though. The second one you mentioned is quite expensive to have done through this private lab.

[Nanaedake in reply to 123454321]

I have read posts on here where antibodies increased and decreased quite dramatically but I think if you had Hashimotos your TPO antibodies would likely be >34. People do sometimes have TgAb antibodies with low TPO antibodies but It's not so common.

Have you looked at online labs such as Medichecks? You can find reliable private online labs listed on Thyroid UK's website. Prices are listed on their website for the various test option.

If you were taking medication or even supplements, herbal remedies I wonder if it could affect thyroid function and therefore blood test results?

[123454321 in reply to Nanaedake]

I don't really take anything at all aside from the occasional multivitamin. Thanks for the replies and I will look into having my TgAb checked just in case. But if that also turns out to be a non-issue, does that mean this could potentially be a one time thing caused by the infection? It just seems so weird that this isn't more common in people if it truly was. Anyways do you know of anything I can do to make my recovery faster? I DO feel slightly better than I did a few weeks ago but I've read on here that certain deficiencies (b12 for example) can make you feel really bad aswell and maybe that's the missing piece for me.

[greygoose in reply to 123454321]

This happens all the time, whenever you have a bug or an infection. It's just that people don't normally get tests for their thyroid during that time, so they don't know about it.

In fact, when people do think they have a thyroid problem, and go for a test, if the TSH is elevated, the doctor will make you wait three months or so, then go back for another test. If the TSH is still elevate, the doctor knows you are hypo, because it would have gone down if it had just been a bug.

"Do you know if excess rT3 is possible to recover from or could the infection have triggered a permanent unhealthy imbalance between fT3 and rT3?"

As it's a normal bodily function, designed to save energy so that the body can heal, it won't have triggered any sort of unhealthy imbalance. Within a few days, rT3 is converted to T2, and when the bug/infection has gone, T3 and rT3 will revert to their normal ratio.

[123454321 in reply to greygoose]

Thanks so much for clarifying. I'm just really worried because even though the numbers became normal after a few weeks I'm still feeling extremely messed up in the head. I don't really know what to look for anymore. I've always been kind of into doing mentally challenging things so any small difference in that area is always very obvious to me. Now in this case I know for a fact that I have very severe brain fog as I have pretty much been monitoring my mental performance for half a year. I'm kind of desperate to get rid of this because I just started Uni and it's really demanding.

edit: Could taking T4 help with my rehabilitation? I'm just thinking since my tsh only went down to 2.8 and the people in this community pretty much all say 1.0 is optimal. I could also find out what my tsh was previous to the infection, I had a lot of blood tests done 2 years ago.

[greygoose in reply to 123454321]

A TSH of 1 or under is optimal for hypo people on thyroid hormone replacement. We need our TSH lower than the average. It could be that your TSH is still going down.

What is your FT4, now? If you take it when you don't need it, one of two things could happen. a) it gives you hyper symptoms. b) it converts directly to rT3. So, it's doubtful you'd feel any improvement. I would not recommend taking T4 unless your TSH goes higher, or you FT4 is under-range.

I notice that nowhere is there a result for FT3. It might be interesting to see that. It's low T3 that causes symptoms, not high TSH or low FT4.

[123454321 in reply to greygoose]

Last time I got tested (2 weeks ago) I had fT4 of 19 (range 12-22) and fT3 of 5.1 (range 3.1-6.8) and a TSH of 2.8 (range 0.3-4.2). The reason I'm posting even though my numbers improved to pretty much normal is that I STILL FEEL THE SAME. I don't know why. And I have a pretty big issue when it comes to completely ruling out thyroid hormones because where I live I can't get my fT3 tested at all. It's really messed up.

[greygoose in reply to 123454321]

Not many people in the UK can get there FT3 tested. Doctors don't understand it.

It's possible that you still feel the same way because you're still recovering from the infection. I had infected insect bites, once, and it took me a long, long time to recover from it. I had a raging fever and halucinations, the whole works! And my FT3 was extremely high at that time. These things can take a lot of time to get over.

But, those Frees are good. They react faster than the TSH. I think you just have to be patient and get plenty of rest and good food.

[123454321 in reply to greygoose]

Thank you so much! This is very comforting to know (although I'm sorry it happened to you). Just to make sure, do you have any thyroid issues right now? What makes some people react so badly to these things? I can't imagine everyone's thyroid hormones take a hit for so many months just because they get a temporary viral infection.

[greygoose in reply to 123454321]

Yes, I've been hypo most of my life.

Everyone's thyroid hormones do take a hit if they have an infection or are starving or in some other sort of desperate situation - most anorexics end up permanently hypo. It's a protection mechanism.

T4, the storage hormone, is converted into T3 and rT3 - normally more active T3 than inactive rT3. The active T3 makes all your millions of cells function correctly. This uses energy - calories. When the body is sick or injured, it needs to direct more energy to healing, so increases production of rT3 - inactive T3 - to make the body slow down, use less energy because it has less T3. That way, it can heal.

But healing some things can take a long time. Especialy when the brain is involved.

And, I assure you, it does happen to everybody, to a greater or lesser degree, because that's the way the body works. It's just that some things take longer to heal than others.

[123454321 in reply to greygoose]

Thank I will keep my hopes up and try to be patient. Maybe I will just have my vitamin D, vitamin B12, folate and ferritin checked like someone suggested just to be sure I've covered all the holes. Are there any other things (like the ones I just mentioned) that could be affected after an infection, since you've experienced it in the past?

[greygoose in reply to 123454321]

Magnesium, zinc? But, I wouldn't say that they were low as a direct result of the infection, because I'd been hypo for a long time before that.

There's no point in testing for magnesium, it will always be in range, but that doesn't mean you're not deficient. Just try taking some, and see if it makes you feel better.

I'm not really sure what you're so worried about. If you think you truly are hypo, or have Hashi's, the only thing you can do is retest your thyroid hormones in a few months. But, your thyroid hormone levels are good. TSH isn't a thyroid hormone.

[123454321 in reply to greygoose]

Yeah sorry I'm just being overly obsessive and paranoid. Thanks again for all your insight it has helped me a lot

[greygoose in reply to 123454321]

Good.

[Treepie in reply to 123454321]

Check out the blood test packages offered by Blue Horizon and Medichecks .The latter usually have deals on Thursdays.

[123454321 in reply to Treepie]

Hey thanks I will for sure

[SlowDragon Administrator]

You could check vitamin D, folate, ferritin and B12

Yes if any of these are too low they can cause symptoms in own right and/or affect how thyroid hormones work

Brain fog can be due to candida or gut issues. Antibiotics can wipe out good gut bacteria

Try improving gut with probiotic

[123454321 in reply to SlowDragon]

Hey, thanks for the reply! Just wondering, could the infection lead to a deficiency in any of these or are you suggesting I check them just to be sure? If it can then couldn't other values in my body be messed up as well? You might be able to tell that I know next to nothing about medical stuff.

[SmallBlueThing]

Apologies if you find this too much of struggle to read at the moment: en.wikipedia.org/wiki/Euthy...

There's also this aspect of what you've been (or are going) through: en.wikipedia.org/wiki/Sickn...

Let things normalize (such that they can) before concerning yourself over test results. From the first link, you'll see that results can be all over the place.

[123454321 in reply to SmallBlueThing]

Wow thanks that first link helped me a lot. Unfortunately I wasn't able to test my rT3. Do you know if excess rT3 is possible to recover from or could the infection have triggered a permanent unhealthy imbalance between fT3 and rT3?

[SmallBlueThing in reply to 123454321]

More here (with rT3): hormones.gr/723/article/thy...

Edited to add: that link has extra stops in it, so won't work. Here's an alternative way of getting to it: tinyurl.com/ycofc4wc

There's also Post Sepsis Syndrome affecting survivors of severe cases. Be positive, but aware that milder cases may also be affected to a degree. sepsistrust.org/support/pos...

[123454321 in reply to SmallBlueThing]

Hey thanks for the links. In the first one there is a sentence that reads: "There was no significant difference in mortality between the two groups and the T4 replacement was detrimental to the restoration of normal pituitary-thyroid regulation". What is T4 replacement in this case? Are they saying that someone who's recovering should not take T4? Thanks again this has helped a lot.

[SmallBlueThing in reply to 123454321]

They appear to have tried supplementing T4 experimentally, in critically ill patients. With fever, I think you'd be on the second level in my leaflet of guidelines, what they call mild systemic upset. More severe signs of sepsis, such as diarrhoea and nausea and vomiting should have you in hospital, on intravenous antibiotics.

I'm currently being treated for an infection, and a recent TSH test shows a rise of 0.1 despite a dose increase. I'm considering delaying my planned increase, to avoid "flogging a dead horse"

Before treatment had started for my hypothyroidism, I had a thyroid function test, also when being treated for cellulitis. My TSH and fT4 were both low-normal. TSH had previously been sub-clinical (just over-range). As my TSH is currently above 1.0, I don't get tested for fT4, but am eagerly awaiting the day when I am. I had a hyper flare about a year ago, and it's taken the intervening months of gradual dose increases after a cut to get to where I am, with a TSH of 2.0. If my low-normal results when infected were, in fact, due to central hypothyroidism, it's recommended to get the TSH down to 0.5, which is what I had for most of last year and aim to achieve again.

I may have been able to proceed more quickly with my dose increases, but have kept it to an addition of 25mcg T4 every other day, every eight weeks or so. I have T3 and NDT available, but am seeing how things will pan out with what some consider to be the worst option: T4 only. I feel better, currently, than during the hyper flare. I wondered if the flare was due to rescheduling other meds, which could've altered the absorption rate, but I've now exceeded last year's dose.

Best wishes for your continued recovery, and that it doesn't take too long.