I have Graves' and Hashimoto's

[Flamegenie2]

Yesterday, my endocrinologist told me I have sub clinical hyperthyroidism (Graves') which I've had since 1999. I was taking 5 mg of methimazole per day and suddenly it stopped working.  So, I went for blood work and my TSH was low (.044) although my T3 and T4 were normal, as usual. This is why I'm always told that I have sub clinical hyperthyroidism.

However, my endocrinologist just told me that the labs came back positive for Hashimoto's antibodies. My question is: Does this mean that I have both disorders?  Does this mean that I will eventually develop Hashimoto's disease? How can I have both conditions?

BTW, I'm 68 years old.   Thanks.

[Red_Star]

I forgot to add I've had both types of Hashitoxicosis and the "leakage" hyperthyroid symptoms of active Hashimoto's are mild in comparison to Graves.

The Medical Journal Of European Endocrinology - Hashitoxicosis – Three Cases and a Review of the Literature...

"It should be pointed out that, especially in the US literature, the term ‘hashitoxicosis’ is sometimes used to describe an autoimmune thyroid disease overlap syndrome of Graves’ and Hashimoto’s disease.  In this article the term is strictly limited to the ‘leakage’ symptoms of active Hashimoto’s disease."

[goolarra]

I know it sounds like a contradiction in terms to have both Graves' (hyper) and Hashi's (hypo ultimately), but it is possible.  One or the other, usually Graves', is dominant first.  When you have both Graves' and Hashi's antibodies, the chances of eventually becoming hypo increase greatly.  

However, keep in mind that, although ultimately hypo, early stages of Hashi's can be hyper or swing from one to the other.

Do you have recent labs to post with reference ranges?

[Red_Star]

I have Hashimoto's thyroiditis and for a couple of months Graves antibodies showed up. The combination of both conditions is sometimes called Hashitoxicosis.  For me, I was VERY hyperthyroid but my labs showed subclinical hypothyroidism. Weird lab results when both antibodies show up.  However, you can have Graves disease with thyroid peroxidase antibodies (TPOAb) and thyroglobulin antibodies (TgAb) and not have Hashimoto's thyroiditis.