I Had Been On Lexapro For Over A Year Before
About low ft4;
Hello and thank you for asking!
I have gone carefully through your query.
Your concern is right, a XXXXXXX TSH with low Ft4 is suggestive for sevondary hypothyroidism but before planning an MRI of the pituitary gland you need to repeat Ft4 and Ft3 agian.
The symptoms and hormonal results are suggestive but to be sure i would suggest to check them again together with Ft3.
If still low, do not hesitate to ask for MRI.