Dear Dr. Grable,
I have been working with thyroid issues for many years and would like to comment on your question regarding the TSH. First of all, I find the TSH to only be relevant in the ‘pre’ treatment evaluation, ie, before adding in exogenous hormone. Yes, when someone is clinically hyperthyroid, the TSH will be suppressed, but most importantly the actual thyroid hormones will be elevated. the actual cause of metabolic pathology (A-fib, osteoprosis, etc) is due to the excess of circulating thyroid hormones, not the TSH itself.
When, patients are treated with Synthroid or Armour, the TSH becomes much less accurate contrary to the way we have all been taught that the TSH is the “gold’ standard. As you may already know the ranges on all of these tests are not established from looking at optimally fit people. Secondly, I have on numerous occasions seen quite variable TSH reading on patients on long standing stable doses of Synthroid to now convince me that the TSH is a big waste of time. (I only order them mostly because it is still the “standard” of care.) For example, I recently had a woman come in on Synthroid 75mcg QD who had a TSH of 1.7 with a Free T4 of 1.38 done on a Friday by her PCP. I drew labs on Monday and she had a TSH of 4.5, a Free T4 of 137, and a suboptimal
Free T3 of 2.3. She had hypothroid symptoms. So, which TSH to believe? I have even sent my own TFT’s off to different labs and found the TSH levels to vary, yet the Free T4’s and free T3’s remain stable. (…and i’m not on thyroid hormone)
I have several patients on either Armour or just Synthroid or some other mix, who are clinically euthroid (subjectively they feel optimal — not “high’ or hyper or hypo), with optimal Free T4’s and T3’s, but with suppressed TSH levels. On physical exams they display NO hyper thyroid signs. Every time they have their doses decreased, they
begin to have hypothyroid symptoms return. So, how do we explain suppressed TSH levels when in fact the Labs (fT4/fT3) and the clinical examination reveal they are euthyroid?
These people are in fact, NOT hyperthyroid despite the suppressed TSH! Please do not treat them by this mediocre test. I think there is a phenomena of the pituitary regulation getting lazy when we take over the peripheral hormone control. (kind of like a driver’s ed
situation where the passenger seat has an instructor who can take over the control of the car and the student drive just lays back….I’m trying to make an analogy here.)
I have had many patients for over 15 years in their middle age to elderly years with optimal fT4/fT3 labs, suppressed TSH levels < 0.1 and subjectively at optimal euthroid quality of life and NEVER had an incident of all the garbage fears the Endocrinologists tell you of such as, ‘heart attacks”, Atrial fib, osteoporosis, etc. Never!
I think the whole role of TSH needs to be revamped in our thinking. we need to go principally by clinical exam, listen to the patient, and use the actual free hormone measurements first.
Feel free to contact me if you have further questions.
Ron Manzanero, MD