very low TSH normal T3 T4..??

[mediman]

Hi all, I am puzzled. I would have posted this in an endocrine tread but I didnt see one. Here goes, How can there be a very low TSH (<0.015) but still have normal T3 and T4? What is telling the thyroid to make TH? How can this happen and what are some potential causes? There are symptoms of hypothyroid that include unexplained weight gain (35lbs over 3mo), fatigue, mood swings, difficulty falling and staying asleep, occasional mild dizziness and headache and mild periorbital edema. No overt signs of hyperthyroidism at all.

[marilynpac]

Boy oh boy those were my symptoms to a T. I had multiple attacks of thyroiditis to the point I went into thyrotoxicosis state of hyper/hypothyroidism. Very, very rare. This person could be in high output heart failure...I was and still am. Ask you patient about bad BURNING sore throats with ear pain that feel like pressure esp left ear. This person needs to be on a beta blocker and HCTZ if this is the case. This patients body is running in a state of "flight" , it's called an elevated sympathetic nervous system. My nervous system was hit so hard I went hard of hearing and had increased intraocular pressure in my eyes. This patient needs help. My numbers TSH .33 normal T3 T4...

[Guest guthriesm]

When my TSH was checked in June, I threw a 0.015 with normal T3 and T4. However by October, my TSH shifted to 6.5 and started climbing. I had no symptoms of hyperactive thyroid and only some of the hypothyroid.

 

Your patient needs a thyroid antibodies test (TPO is most common). Hashimoto's Disease is one of the most common causes of hypothyroidism. Due to the excess autoantibodies, the thyroid goes NUTS. Be especially suspicious of Hashimoto's if your patient is young as it typically presents around age 30.

 

If the antibodies are over the limit (TPO should be <60) then you can assume they are suffering from Hashimoto's and start a treatment plan.

 

Sounds like marilynpac has some good points too- be watchful as the thyroid will swing until finally it peters out. If his symptoms continue to be severe, you may need to look at more definitive treatments like surgery.

[marilynpac]

Actually the difficulty falling asleep and staying asleep is a sign of hyperthyroidism. Do the antibody test and if everything is neg....If positive then you know which direction you will have to go. After all the multiple attacks I grew a hot nodule which threw me into severe hyperthyroidism, the surgery was a Godsend, but you don't want your patient to have to go through this...

[Guest guthriesm]

Good point- is there a nodule? If one can be palpable then an ultrasound would also be a good next step. Also, weight gain can be seen with hyperthyroid. It isn't as common but can be associated because of the increased appetite.

[mediman]

Thanks for the input. This was not actually my patient but a 36 y/o female patient that I saw when I was shadowing. It was a very busy day in the office so I didn’t really get to ask too many questions. The PA I shadowed did repeat the TSH free T4 and T3 (came back the same) and also ordered the auto-antibody test which was still pending. I just don’t understand the physiology behind a non-existent TSH but having a normal T3 T4... how is that possible? If its Hashimoto's how can there be such a huge weight gain accompanied with all those hypothyroid signs but have NO TSH at all? This patient had no signs or symptoms of hyperthyroid at this time at all, she was not tachycardic(70/min) and had normal BP (110/82). The PA did note that on PE the patient did have an enlarged thyroid and was going to order an US of the thyroid. Also the patient stated that she gained all the weight over the summer and during that time she was very moody ("crying a lot one minute then angry the next") and she was very sensitive to the heat and had hot flashes and sweating as well as some "racing heat episodes". I guess overall I am just so confused because this woman seemed to be both hyper and hypo thyroid, how is this possible????? I thought I had a decent grasp on endocrinology but I just cannot wrap my hands around this at all....

[MCHAD]

Thyroid has to be acting on it's own if it isn't getting the signal from TSH to produce. well...that or she is on meds and isn't telling you :)

[marilynpac]

No, if you look up thryoiditis one of the rare, extremes of it are a hypo/hyperthyroid state that the patient can go into. I was lucky I went to a Endo that had seen it b/f and said your hypo and hypertyroid at the same time, very rare. She had been in practice for over 20yrs and had only seen it one other time. Now she can add 2x to her belt. To the OP, on the panre I had taken b/f I got 100% on endocrinology and I still didn't know it...it's that rare.

[mediman]

Interesting. Well I go back to that office to shadow again next week and I am going to try and follow up, I will let you all know if I find out anything new. Thanks for all the great feedback. I feel as though this is one of those cases to tuck away somewhere for future reference.

[cecilia]

how do her other hormones look? especially because she gained lots of weight? sweating a lot? moody? I would definetly check 24hr cortisol

[mediman]

Hi again. I have an update on the low TSH women. So I went back to shadow today and the woman came in for an apt. It turns out that her TSI level was 398% (normal is 0-2% so Ive been told)! So her problem is Graves disease. She was referred to an endocrinologist, had an iodine uptake scan which was 40% which confirmed Graves disease. She was started on beta-blockers and tapazole. She came in today due to edema and a 10 lb weight gain. The doc in the office today wrote a script for lasix and referral for an echo and is thinking high output heart failure.