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Unexplained Fever & Hyperthyroidism

Let me preface this by saying I do have a history of Graves disease (diagnosed 17 years ago) and have been in remission for 5 years.
I have had daily fevers ranging from 100.4-102.6 for the past 5 months. Other symptoms I've experienced are night sweats, extreme fatigue, swollen glands in my neck & groin, painful nodules behind my lower knee/thigh area, high blood pressure, tachycardia, hand tremors, & chest pain. I was told I am positive for strep  (without experiencing a sore throat) in Jan, Feb, April, and May. I've been on at least 4 rounds of antibiotics during those months. Fast forward to my latest visit last week where my doctor told me she doesn't think my fever and symptoms are caused from strep at all, but that I'm a carrier. She ran new tests for lyme disease, thyroid panels, and planned to refer me to an infectious disease doctor.

I got my lab results yesterday showing all tests for Lyme were negative. She said my TSH and Free T3 are indicative of hyperthyroidism and scheduled a thyroid uptake scan for this coming Wednesday. In her note she added that she believes this could explain my "low grade fever" tachycardia, high blood pressure, and she would no longer be referring me to an id doctor!

Lab Results

TSH:    <0.005 (0.450-4.500)
T4:        9.4 (4.5-12.0)
T3 Uptake: 33  (24-39)
Free T4:   3.1 (1.2-4.9)
Free T3:   7.7 (2.0-4.4)

I am so frustrated because in all the years I've dealt with hyperthyroidism and Graves disease, never once did I experience a fever like this and never in my life have I had one this long go unexplained. I have heard of thyroid storms causing a fever but that is certainly not what's going on here. I am at my witts end and don't know what to do. I called my endocrinologist and scheduled an appointment for this week to discuss it all with her. I hope she can get me the proper referral to help get this figured out. I wish I knew what to ask for.

I would like to add my doctor also performed the following labs:

WBC: 7.5 (4.0-11)
HGB: 15.9 (12.0-16.0)
HCT: 45.7 (36.0-46.0)

Platelets: 288 (150-450)
Sed rate: 3 (0-20)
4 Responses
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649848 tn?1534633700
I agree that your symptoms and labs, both indicate hyperthyroidism.  

We have to keep in mind that TSH is merely and indicator of what's happening because it's a pituitary hormone, not a thyroid hormone.   Any doctor who goes only by TSH is going to keep their patients ill because they aren't looking at the full picture of what's happening.

It's necessary to test Free T3 and Free T4 EVERY time you have labs done.   My TSH was suppressed for years which made everyone think I was hyper, but my FT levels were always low/below range, indicating something else going on and I never did have hyper symptoms.  Because your FT3 is much higher than the upper reference range and you have quite a few symptoms of being hyper, that would be the logical conclusion.  

Being hyper can cause inflammation, which, in turn can cause a low grade fever.  

Did anyone go ahead and test your thyroid antibodies?  If so, which ones and what were the results, with reference ranges?   In addition, have you had a recent ultrasound or has anyone mentioned doing a nuclear scan? If you have nodules, there could be one (or more) producing hormones independently of the thyroid.  

Most doctors don't like to keep people on anti-thyroid medication for long periods and the preferred treatment is either RAI or surgery.  
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Avatar universal
I finally saw the ID specialist who did a thorough investigation and nothing showed any sort of infection. Although I have only been on methimazole for 3 weeks she retested my TSH which is 0.015.

She also sent me for an ultrasound of my groin to investigate a swollen lymph node. It came back as enlarged with a fatty hilum (likely benign) but with markedly lobulated/irregular borders (abnormal). She said she wasn't worried about it and it was fine.

Like my primary Dr, she also belives my thyroid is the culprit of my fever and asked what my endo said about it. I told her my endo said hyperthyroidism can certainly raise body temp, but that it didn't explain Jan-April when all my thyroid labs were completely normal.

My primary doctor is ready to close the book on this issue, and the ID specialist has exhausted all infectious causes. I am not sure where to go from here.

I sat down and cried today because all I know is I am not well! I woke up at 3 am today soaking wet, fever of 100.9, and the nodules behind my knees and in my groin ache really bad. If anything I feel worse.
Helpful - 0
Your TSH is quite low which would suggest that you might still be on the hyper side, especially if you have been taking methimazole.  Share the results with your endo.  Do you have an elevated heart rate?  When you extend your arms in front of your chest and stretch your fingers out, do you notice a slight tremor?   If yes to all then those are early signs of hyperthyroidism.  Have you seen a hormonal specialist?  Not all endos have the extensive background that you need in dealing with the spectrum of hormonal disorders.  Since you are eliminating things, get a Lyme test.  

It is frustrating, but try to focus on one thing at a time so you can eliminate each cause systematically.  What you are going through is very  difficult but there is light ahead and eventually you will get there.  Stay strong and you will persevere at the end.  
Avatar universal
I just left my endo appointment. She said the only lab value that she looks at is tsh and based on that I'm extremely hyper as my tsh is almost completely supressed and I'm having a recurrence of Graves. She prescribed 10mg methimazole to take once a day. It's weird because I remember my 1st endo before she retired always said tsh is not the only value to look at, so now I'm a little confused. I spoke with her about the fevers and she said most Graves patients may not be aware that their temp is up, however it usually is elevated. She said I should consider radioactive iodine to kill my thyroid and switch to levothyroxine because it's better to take hormone replacement than to be on methimazole. She's giving me some time to think it over before my next visit in 6 weeks. I'm honestly not sure what to do, but not looking forward to being permanently hypothyroid because that also brings it's own share of symptoms. If anyone would like to share their experience with RAI that would be appreciative.  
Helpful - 0
I had it done 25 years ago.  It was a pretty smooth transition and had great success with levoxy.  It took about several months to get the right dose.   I stayed on the same dose for 20 years.  There were no side effects from my experience.  HOWEVER, once you make the decision to do the RAI you can't go back.  I read an article (please google it) that compared the 3 treatments: radiation, surgery and anti-thyroid medication.  The study interviewed patients for their feedback and my recollection was that most fared better with the anti-thyroid medication over a 10 yr period.  Now the medication does have long term side effects and I was told the same as you.  Like with all drugs it depends on the dose and duration.  I would ask your dr about trying it for 6-8 mos and see if it would go into remission again.  You can always get a second opinion too.  RAI and surgery should be the last two options.  

TSH is a good early indicator.  Since your level was so low it was pretty conclusive.  
Avatar universal
I really don’t have any advice, but I just wanted to say I hope you feel better soon. 5 months is a long time to not feel well and have no answers. Sending my prayers.
Helpful - 0
Thank you so much for taking time out pf your day to send positive thoughts my way! At least my primary doctor has tried testing me for a few things. At this point I just want a proper referral to someone who can look at all my test results as a whole, see what's already been ruled out, and go from there. My thyroid doesn't look all that bad to me. I don't understand why she's trying to blame my fever on it. Best I can hope for is when I see my endo Wednesday after the uptake scan she might be able to point me in a better direction.
There are a few sources online that indicate that Graves’ disease can cause fevers:

Can Graves disease cause fever?
The sudden and drastic increase in thyroid hormones can produce many effects, including fever, sweating, vomiting, diarrhea, delirium, severe weakness, seizures, irregular heartbeat, yellow skin and eyes (jaundice), severe low blood pressure, and coma. Thyroid storm requires immediate emergency care.

Can thyroid disease cause fever?
Fever is a common clinical manifestation of inflammatory processes of the thyroid and thyroid crisis.

The information I pasted above is from the Mayo Clinic and ncbi.com.  Maybe she believes there is some connection. I know you stated you have been in remission for a while, maybe it’s flaring back up? The body is a weird thing and sometimes it feels foreign when it doesn’t do what we expect. I hope it’s something not serious and something that is easily balanced or corrected. Health issues make life hard to live.
I am not super familiar with thyroid tests but your TSH is basically undetectable - are you taking meds?
I have not been on methimazole since 2016 I believe. My primary doctor has been the one monotoring my thryroid levels ever since I achieved remission. Now that she believes I am hyper again I have gone ahead and scheduled an appointment with my endo beacuse my primary has no idea how to dose methimazole correctly. I have never experienced a thyroid storm before but my blood pressure started getting high the same time I began running fever. I guess I'm a little skeptical of my thyroid being the culprit due to my levels being fairly normal up until now and I've had the fever daily for 5 months. I will go ahead and post my previous thyroid panels here to see what you might think.


TSH:           0.026  (0.450-4.500)
T4:               7.7       (4.5-12.0)
T3 Uptake: 30       (24-39)
Free T4:      2.3       (1.2-4.9)


TSH:            1.030 (0.450-4.500)
T4:               6.0     (4.5-12.0)    
T3 Uptake:  26   (24-39)
Free T4:       1.6     (1.2-4.9)


TSH:            0.018 (0.450-4.500)
T4:                7.5     (4.5-12.0)
T3 Uptake:  29    (24-39)
Free T4:       2.2   (1.2-4.9)

I would like to add that she never tested Free T3 until my most recent set of tests. I do realize that my TSH has been fluctuating and it is a possibility that the Free T3 may have been high this whole time and we just didn't know it. I'm sure my endo will check my auntoantibodies this week too. I know my values have been worse than this before and never had a fever as a result. But you could be right about my body reacting different because I have been in remission so long. I know I'm ready to figure it out so I can feel better and get back to work. I can't work until this fever is gone because I'm a radiologic technologist at a hospital and if your temp is above 100.4 they send you home with covid fears. I've been negative for covid this whole time but something is going on and until I can prove I'm not contagious, they won't let me work.
Try not to get too worked up about your results.  Your visit to the endo on Wed should give you another data point.  Your TSH and Free T3 are off so something there has to be corrected.  On  the positive side thyroid conditions are very  treatable and with minimal serious side effects.  Remind yourself of that, stay positive  and Wed should provide some answers.  Good luck!
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