TSH normal, FT4 elevated, hyperthyroid symptoms-grave's disease possible?

[chrisrob3312]

I am Type I diabetic of 13 years that began having hyperthyroid symptoms 6 months ago, which included tachycardia 100s-160s, palpitations, fine hand tremor, heat intolerance & hyperhidrosis, occasional chest tightness, development of diffuse goiter over past month, and dyspnea with exertion at times, as well as it seemed to take longer than usual to focus eyes when reading electronic screens. Saw my GP a month ago and had TSH, FT4, and T3 drawn. TSH came back within normal limits (1.2 or 1.6 with ref range 0.4-5.6, I think) and fT4 was 2.4 with upper end of ref range 1.4. The t3 was within normal limits. Along with the hyperthyroid symptoms, I have had a few occassional severe migraines wtih pre-migraine visual disturbances and numbness to hands over past couple months. Migraines have not been an issue for me in the past and the ones I experienced over past couple months weren't frequent. Was referred to endo who I saw today and she ordered ft4, t3, and tsh levels to reconfirm along with antibody screens. I haven't received these back yet. Autoimmune and thyroid disorders tend to run in the family and I know grave's is most common culprit of hyperthyroidism. However, I know that tsh-secreting pituitary adenomas and PRTH may cause normal-elevated tsh with elevated ft4, but that these are rare causes. If the second round of bloodwork continues to show elevated ft4 but normal tsh, can grave's occur with this configuration?

[chrisrob3312]

yeah, I figured as much- that lab error was most likely.

[Mark Lupo, M.D.]

Most likely it's a lab error as the TSH and T3 were normal.
Repeating the tests, as the endo is doing, is appropriate before any consideration of the other rare causes (TSH secreting tumor or thyroid hormone resistance).

  You are right that as a type 1 DM patient, there is an increased risk of Graves so this should be explored given the symptoms.