Congential Hypothyrodism

[lmf17]

My son was born 2 months premature.  His newborn scan showed "moderately elevated" levels of TSH.  The newborn scan was repeated with the same result (I guess it's repeated because preemies often have elevated levels of TSH initially).  The NICU doctors then ran a blood test and the TSH levels came back over 300.  So, he was started on 50mcg of Levothyroxine/daily.  Should I worry that treatment wasn't started until day 18 of his life?  Does 50mcg sound like a reasonable dose (he is just over 4lbs now).  What is the long term prognosis?

[lmf17]

As a follow up question - After 3 days on 50mcg/daily, my son's heartrate was elevated so the Dr's checked his levels again.  His TSH was 12 and his T4 was 2.71 (was originally less than .5).  Do these results seem reasonable after 3 days?  I was told we would have to wait 4-6 weeks to see any significant change in TSH levels.  

[Deanna L Aftab Guy, MD]

you are right, tsh can rise later in premies and need more time to come down, but whew over 300 this is indeed congenital hypothyroidism, and indeed thyroid hormone was indicated, you should be fine with treatment started at that time, the dose sounds appropriate, usually it is about 7.5 to 10 mcg per kg starting dose but with the tsh that high sometimes we go higher, wait for repeat labs, followup with peds endo