Primary or Secondary?

[MissFG]

Please could someone briefly explain what the difference between Primary and Secondary Hypothyroidism is? I’ve seen it mentioned but don’t understand what they mean and curious thanks

[SeasideSusie Remembering]

Primary hypothyroidism is where there is a problem with the thyroid gland. Diagnosed when TSH is over range/FT4 low or below range.

Central hypothyroidism covers both Secondary where the problem lies with the pituitary gland and Tertiary where the problem lies with the hypothalamus. Diagnosed when TSH is either low/normal/slightly raised and FT4 is low in range.

[MissFG]

So what do I have if I have Hashimotos? Thanks

[helvella Administrator Thyroid UK in reply to MissFG]

Hashimoto's is a cause of deterioration of thyroid function. The thyroid itself is progressively destroyed by the immune system.

After a certain point, the remaining thyroid is unable to keep producing enough thyroid hormone. Hence, the result is hypothyroidism.

Therefore, it is primary hypothyroidism.

Just don't go thinking anything is that simple! It is entirely possible for someone's pituitary or hypothalamus to also be under-functioning.

Also, sometimes you will see "tertiary" applied if under-functioning hypothalamus is the cause. Or "central" either to cover both secondary and tertiary - or if no-one has gone on to decide which it is.

[MissFG in reply to helvella]

Thanks but I know after suffering with hashimotos for 2 very hard years it not simple. All autoimmune diseases are complicated unfortunately. But I’m trying to learn all I can to not only help myself but also others hence the post 😊