Low T4, borderline Low TSH, any advice?

[Sandalgrinder]

I have posted previously under another username about my DS (12) who had bloods done due to tiredness, lack of stamina etc.

First set showed free T4 of 10.33 (11.43-17.59) and TSH of 1.066 (0.700-4.170).

GP repeated them four months later and they showed T4 of 10.16 and TSH of 0.912.

She referred to the Paediatrician with a query of subclinical hypothyroidism. She doesn't seem overly concerned but said he might be "becoming hypothyroid".

We saw the Paediatrician today and I realised afterwards that I don't think he actually had a copy of the above results/ figures just the GP query. He has ordered a whole further set of blood tests that mostly seem to be immune markers and more detailed thyroid tests for antibodies etc.

My concern is the unusual pattern of a low T4 but a normal/ borderline low TSH. From my readings online, the TSH should be high when the T4 is low. I guess if this is still the case (the last bloods above were taken 3 months ago) then the Paediatrician will know this when the results are back. I just wondered if anyone has experienced anything similar? And can offer any advice? Should my DS be seeing an endocrinologist? I'm starting to worry a bit that time is going on and nothing much is really happening.

Many thanks in advance.

Just bumping

Sounds like secondary hypothyroidism, which presents with 'normal' TSH, but low FT4 and FT3 and is often caused by pituitary damage. Has your DS had a bang on the head, fallen off his bike, something like that.

You are right that usually hypothyroidism presents with higher TSH and lower thyroid hormones, but that's primary hypothyroidism, which is more common and more likely to be picked up.by NHS testing.

Your GP may never have heard of secondary hypothyroidism so I recommend that you do your own research and then tackle him.

Thanks so much for replying I appreciate it. He went over the handlebars on his bike about 6 years ago but had cuts and bruises to his face, no symptoms of concussion etc. He’s definitely had no bangs to the head or injuries since. I’ve read some stuff about this potentially being a pituitary thing and it’s really scary! I feel this is not on their radar though. That’s why I’m wondering whether I should ask for another referral. If they suspected a pituitary issue presumably they would do a brain scan or something? The Paediatrician today said we’ll do these bloods and see him again in 6 months.

Sorry just bumping again in case anyone had any further advice particularly in terms of whether/ where I should be seeking a further referral. Thanks.

In your position, I would do some research and then push for proper evaluation, yes.