Subclinical Hyperthyroidism

[Alio_Ditty]

I wanted to have some lab ran because my days between menstrual cycle was 20 days for 2 months in a row. Has since returned to normal. TSH is 0 (0.3-4.8), T3 is 119 (76-181), T4 is 1.2 (0.7-1.6), Thyroid Antibodies 262 (<35). Subclinical hyperthyroidism? No symptoms other than stalled weight loss. Only possible significant history is intentional weight loss over the past year of around 60lbs by healthy diet and cardio. Previous TSH 3 years ago was WNL. Again, I am asymptomatic.

We are looking at possible conception in the near future and am wanting this evaluated. In my area, the soonest appointment for endocrinology is in August.

1) What is the next lab or diagnostic exam that my ENT may recommend at my upcoming appointment? My research discovered a Radioactive Iodine Thyroid Scan and Uptake Test. Is that correct?

2) Could my weight loss and diet/exercise have caused this?

[Alio_Ditty]

Also, what is the difference between 1-131 Uptake Scan versus 1-123 Uptake & Scan?

[Alio_Ditty]

Thanks for the reply. Would a thyroid ultrasound be of benefit before the uptake scan?

[Mark Lupo, M.D.]

Probably the next test would be the I-123 uptake/scan.  Your are correct that this is subclinical hyperthyroidism and appears to be autoimmune in nature.  This may be a transient thyroiditis (inflammation) or Graves' disease.  In either case this needs to be confirmed and stabilized before trying for tendency.