Hypothyroidism or a pituitary issue

[Melissa6204]

Hi.  I am really hoping that someone may be able to help guide me in the right direction, I am currently waiting to hear back from his doctor, but when it comes to my son's health, I am just very impatient and I am concerned that it could be an issue with his pituitary gland.

My son is 12 years old, he had low T4 levels when he was 5, 2 separate tests, then the 3rd was normal.  Recently, he has been getting very frequent headaches and he has had quite a bit of weight gain over the past 6 months, no matter what he eats, he keeps gaining weight.  His primary doctor tested his thyroid again.

7/11/16
Free T4 Assay 0.7 ng/dL (Low)   Normal range: 0.9 - 1.4 ng/dL
TSH 3.49 mIU/L                          Normal range 0.50 - 4.30 mIU/L
7/15/16
Free T4 Assay 0.8 ng/dL (Low)  Normal range 0.9 - 1.4 ng/dL
TSH 4.55 mIU/L (High)     Normal range 0.50 - 4.30 mIU/L

They also ran a CBC, everything there was normal.

He was referred to an endocrinologist, more tests were done:

Bone age study indicates that he most closely corresponds to the bone age of a 13 year old
Free T4 Assay Dialysis Method  0.8 ng/dL (Low)   Normal range 1.0 - 2.4 ng/dL
Thyroglobulin Antibody <1 IU/mL Normal range: < or = 1 IU/mL
Antithyroid Peroxidase AB <1 IU/mL Normal range: <9 IU/mL
CBC all normal
TSH 2.35 mIU/L      Normal range: 0.50 - 4.30 mIU/L
Free T4 Assay   0.8 ng/dL (Low) 0.9 - 1.4 ng/dL
C-Reative Protein 0.10 mg/dL Normal range: <0.80 mg/dL
Somatomedin
IFG1        167 ng/mL Normal range: 146 - 541 ng/mL
Z Score     -1.5 SD Normal range:-2.0 - +2.0 SD

So as you can see the only thing that is abnormal is his thyroid levels and my concern is because from my understanding, when he has a low T4, his TSH should be elevated, but it is not and from my understanding, this can be more of an indicator of a pituitary issue, but hisT4 levels are not that low, so should I be concerned?  Could this still mean a pituitary issue?

Thank you for your time,
Melissa

[Melissa6204]

Thank you so much for your response, it was very helpful.  I have been reading a lot about this issue over the past month.  I did hear back from the doctor and she said that before she starts him on medication she wants to check his blood work again in 30 days, they are investigating a possible problem at the lab, so more waiting for us.  If the results are the same or similar than I will be sure to have them do whatever they need to do to determine the underlying cause, rather than just giving him medication.  I don't want to take up too much more of your time, but do you know what other tests would be helpful to further investigate the dysfunction of the hypothalamus/pituitary system?  I just want to be prepared in case they do not ask for him to do anything further other than medication.

I reviewed the list of symptoms and he does have fatigue at times, constipation, muscle pain, and aches as well.

The other link that you provided is very helpful as well, I have not had a chance to read it all yet, but I will finish reading it tomorrow.

Thank you so much for your time!

[gimel]

In assessing for the possibility of hypothyroidism, the most important indicator is symptoms.  Please have a look at this link that lists about 26 of the most frequent hypothyroid symptoms and see if he has any others besides the headaches and weight gain.  

http://endocrine-system.emedtv.com/hypothyroidism/hypothyroidism-symptoms-and-signs.html

Your son's test results show the biologically active thyroid hormones Free T4 and Free T3 as being lower than needed by many people.  Understand that each person may have slightly different levels at which they feel best; however, the ranges are so broad that being in the low end, along with symptoms,  is frequently indicative of hypothyroidism.  

There are two basic types of hypothyroidism, primary and central.  With primary (Hashimoto's Thyroiditis) the autoimmune system produces antibodies that attack and eventually destroy the thyroid gland.  As this occurs, the output of T4 and T3 is diminished and the TSH rises in an effort to stimulate more output.  That is not the case with your son, who appears to have central hypothyroidism, which is a dysfunction of the hypothalamus/pituitary system that results in TSH levels that are too low to adequately stimulate the thyroid gland to produce hormone.  So the doctor may well want to investigate that further.

As you proceed with this, keep firmly in mind that a good thyroid doctor will treat a hypothyroid patient clinically by testing and adjusting Free T4 and Free T3 (not the same as Total T4 and Total T3) as needed to relieve symptoms, without being constrained by resultant TSH levels.  Symptom relief should be all important, not just test results, and especially not TSH results, when taking thyroid med.  

You are going to need to be your son's best advocate in order to assure adequate treatment.  So I suggest that you read and absorb all you can about diagnosing and treating hypothyroidism, in order to assure that the doctor treats your son effectively.    As a start on that I recommend reading at least the first two pages of the following link.  The inherent suggestions may not coincide with the doctor's general approach,  but you will find everything is supported with scientific evidence.  Among the suggested tests you can note cortisol.  In view of the apparent hypothalamus/pituitary issue I think it is especially important to make sure of adequate cortisol levels.  

http://www.thyroiduk.org.uk/tuk/TUK_PDFs/diagnosis_and_treatment_of_hypothyroidism_issue_1.pdf