Resistance to Thyroid Hormone?

[VictoriaT]

I'm a 20yr old female student and competitive runner. For the past 2 years I have had fatigue and am unable to run since 1 year ago. I had iron deficiency anaemia 18 months ago and after taking 3 iron pills a day, was able to run strongly for 3 months although I was suffering from insomnia and depression still. Then, after 3 months I got an injury and haven't been able to function properly since (injury fine). My iron levels are very good but ferritin was always on the low end of normal. I also have inherited high cholesterol which has got higher during the past 2yrs.

I have most of the hypo symptoms (fatigue, dry hair, joint and muscle pain, depression, cold) and also some hyper ones (exercise intolerance, insomnia, hot flushes, muscle weakness). Also have purple marks on bottom/breasts and swollen breasts.

                 unit        range
FT3   0.36                 ng/dl       0.2-0.44
FT4   1.53                 ng/dl       0.93-1.7
TSH *   9.92                 uUl/ml        0.27-4.2
ANTIBODS                     NEGATIVE
am cortisol (blood) * 21.18 ug/dl        6.2-19.4
DHEA-S * 437.5          ug/dl        35-430

Endo diagnosed subclinical hypothyroidism and started meon 50mcg levo.  My TSH was 3 then 5, now 9). However, he said I had too many symptoms for it to just be sub hypo. He's testig 24hr cortisol. He wants to lower my TSH to just 5mmol/l (I was feeling ill when it was 3mmol/L).

Is it possible that I have Pituitary Resistance to Thyroid Hormone given my high T4 and T3? My father has a TSH of 10.3mmol/L and is tired lots of the time.

[Mark Lupo, M.D.]

The T4/T3 you list are not high and I do not think you have TH resistance.  I agree with cortisol eval. Keep the TSH around 1 in most cases.  Ultrasound thyroid - this may pick up cases of antibody negative Hashimoto's (to explain the high TSH).

[VictoriaT]

Thanks very much. Can anyone give me more info on negative antibodies Hashimoto's? Can high cortisol be linked?