Disturbances of thyroid hormones produce clinical symptoms but hormonal level at which this happens vary from patient to patient. In order to determine how much hormonal change patients can tolerate before developing symptoms we retrospectively collected data of 86 hyperthyroid and 48 hypothyroid patients, 120 females and 14 males aged 2885 and 2374 yrs respectively. We included only patients who at some time during treatment had abnormal values of TSH and/or thyroid hormones and/or antibodies but had no disease symptoms at all. We found that patients tolerate TSH values from low <0.005 to high 60 and even 105 mIU/L without any complaints. On 94 occasions TSH was below and on 72 above normal levels, majority of elevated values up to 30 mIU/L above upper normal limit. Free thyroxine ranged from <2.0 to 75.6 pmol/L(n.v 9.816.8) with majority (52) of elevated values up to 20 pmol/L above normal; few patients had higher values (1 up to 30, 5 up to 40, 2 up to 50 and 1 up to 80 pmol/L above upper normal limit) and at that time without any symptoms. Asymptomatic patients had free triiodothyronine from 1.4 to 36.8 pmol/L (n.v.4.67.8), majority of elevated values (49) up to 15 pmol/L above upper limit.
46 euthyroid patients with positive thyroid antibodies had no symptoms, 3 patients had symptoms but also other problems. We conclude that many patients have no symptoms at all with hormones slightly, moderately or even extremely elevated or decreased. Our patients do not feel positive thyroid antibodies. The cause for this phenomenon probably involves thyroid hormone receptors and/or sympathoadrenergic system.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector
05 - 09 May 2012
European Society of Endocrinology