11 yr old with secondary hypothyroid

[Kelly4577]

My son was recently diagnosed with tiny pituitary tumor that is causing a t4 thyroid suppression only. We discoverd this because I noticed a change is school effort/grades. Also his hair was falling out in clumps. The problem Im facing is having his school understand this could be the cause of his sudden lack of focus, intrest, and memory. His Endo agreed and said in time with meds he will level out feel better and return to normal. BUT.... will not put this in writing for school? My sons primary Dr will though. My question is, could this really be effecting his school preformance. He has had no other new or different things going on at home in his life other then this illness. He has been in a Talented and Gifted School straight A student in acedemics and effort for the past 4 years. Since November he is now a C student and poor effort. At home I noticed the same lack of focus. He forgets EVERYTHING. All of this came on the same time we found the thyroid problem? If it could be caused by his illness we should see a change when his levels straighten out right? Or am I reaching here and should exclude thyroid as a factor? Any help or guidance will be appreciated.

[Kelly4577]

Thanks for the fast help. I am in the process of a second Endo opinion. His tsh is normal, but his t3 was elevated and t4 was low. At first the Endo was confused, he had mentioned he has seen this in children who take high dose antidepressant meds? My son has never been on any meds til now, so of course the MRI was in order. He did find a 3mm by 3mm tumor. He has had 3 sets of labs done and from what I was told EVERY area has been tested, ex diabetes, adrenals, etc and all is well? So treatment for today is 75mcg of Levoxyl daily and a yearly MRI, and monthly labs to check for changes in all endo organs? But again I will def get a second opinion and hopefully discuss my concerns with a Dr who can direct me to other areas to explore.
Thank you again.

[Mark Lupo, M.D.]

An isolated low T4 (with normal TSH and T3) is not the typical presentation of a pituitary cause of low thyroid.  It is possible, but keep in mind that pituitary microadenomas (small tumors) are quite common (up to 10% of young adults) and this may not have anything to do with the low T4.  Also, there are typically other pituitary hormone problems and not only hypothyroid.

Usually would retest T4 using different methods at different labs before making a diagnosis of low T4 (hypothyroxinemia) in this setting.  

It may not explain the behavioral changes therefore thyroid treatment may not help.
Would consider a second opin from an endocrinologist (especially since a letter is not forthcoming from the current) and also consider neuropsychiatric testing to help clarify the source of the problem -- ie medical vs behavioral.

I am not saying that thyroid is absolutely not the cause, but would continue to explore other possibilities.