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Doubts about necessity of levothyroxine for subclinical hypothyroidism

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  • Doubts about necessity of levothyroxine for subclinical hypothyroidism

    Hello Doctors,
    having recently listened to the BBM podcast on screening and having read some posts on the forum from Austin about similar topics, I've had some of my doubts about the necessity of taking levothyroxine enforced and I'd be grateful if you could perhaps weigh in on this, insofar as it's not beyond the scope of this forum of course.

    So a few years ago my family doc (internist) brought up the possibility of subclinical hypothyroidism after a blood test for a different issue came back with a TSH of 3.5 mU/l. It prompted him to perform a sonography of my thyroid, where he found a nodule which he identified as a benign cyst, but sent me to a specialist to be sure. She reaffirmed the diagnosis of it being a small (4mm) cyst, otherwise noted my thyroid was on the smaller side for a male (total volume 11ml), but otherwise nothing abnormal to be found. She also performed more complete labs, TSH came back at 3.4 mU/l, stimulated (nose spray) TSH at 29.5 mU/l (high), slight vitamin D deficiency (was prescribed 2000 I.U daily for this), otherwise everything good and within normal range, fT3 at 5 pMol/l, fT4 at 16.7 pMol/land specifically no antibodies for Hashimoto's and the like. I didn't have any symptoms of hypothyroidism as far as I could tell, and no local symptoms from the cyst either.

    She ended up prescribing 25 mcg levothyroxine in what the report described as both substitution therapy and (translated from German, unsure of correct English terminology) "antinodose" therapy (suppression of further growth I'm guessing), and recommendations for follow-up screenings for (obviously) blood levels and also regular sonography. Family doc eventually raised the dosage to 25/50 mcg alternately based on TSH. Most recent TSH is 1.9, fT3 3.27 pg/ml, fT4 1.29 ng/dl.

    My issue is that ever since I started taking levothyroxine, I periodically experience either hair or body hair loss (never both at the same time, strangely), not enough for it to make a visual difference on me, but especially in the case of the body hair loss enough to litter the bathroom floor with body hair. Tends to last for a few weeks, then goes away. Told my doc, he conducted a full hormone panel, everything normal, but suggested that maybe the levothyroxine dosage is too low, since my TSH still is relatively high. This confuses me however, as I don't see how a symptom could be caused by taking too little medication when I didn't have the symptom at all when I was taking no medication, so we've stuck with the dosage. I also at times feel a little restless, though I realise this is vague. So my questions are basically:

    1. Can symptoms of hyperthyroidism be caused by taking levothyroxine even if thyroid markers in the blood are all within normal range? Likelihood?
    2. Could the dosage actually be too low?
    3. Is there actually any merit to using levothyroxine to suppress (further) growth of a benign thyroid cyst?
    4. Would you have initiated treatment in an asymptomatic patient like me if you incidentally found them to have thyroid levels/sonography findings like mine?

  • #2
    1. No. Thyrotoxicosis would be evidenced by a suppressed TSH and/or elevated thyroid hormone levels (FT4/FT3).

    2. That is not my impression based on the information you've provided here.

    3. I see no reason to do this.

    4. I would probably not have pursued any further evaluation or treatment beyond your initial TSH of 3.5; this does not even fit the diagnosis of subclinical hypothyroidism, but even if you did by lab criteria (since subclinical hypothyroidism *by definition* is asymptomatic), we typically do not initiate treatment until the TSH is greater than 10.
    IG / YT


    • #3
      Thanks a lot Austin! Is there any benefit at all then in keeping TSH levels lower, or would you say discussing coming off the medication with my doctor would be reasonable?


      • #4
        In the absence of any symptoms suggestive of clinical hypothyroidism, not that we have good evidence to support.

        For folks who do have clinical hypothyroidism, some folks do report better when treated to certain TSH ranges, although this is by no means universal.
        IG / YT


        • #5
          Thanks again Austin.