'Hashitoxicosis'

I am caring for a 16-year-old girl who presented with typical Graves' disease and a thyroid gland that was more than twice the normal size. It was clearly visibly enlarged, but there was no thyroid bruit or thrill. There were no eye changes typical of Graves' and no peripheral manifestations aside from tachycardia and brisk deep tendon reflexes.

After discussing the treatment options with the patient and her mother, it was elected to treat with radioactive iodine (RAI). Her RAI uptake was 60% and she was treated 3 months ago. The treatment was successful in that she became profoundly hypothyroid about 2 weeks later. This diagnosis was based on the lab data, not on any overt clinical manifestations.

With one major exception!

Her thyroid was growing in size, not decreasing, and this continued as she became biochemically euthyroid when treatment with thyroxine was initiated. She remained euthyroid until now, but there has been no reduction in the size of her thyroid gland; it is not enlarging either.

Her thyroid antibody titers are very high — >1,000.

I had not previously encountered this response to RAI therapy for Graves' disease so I contacted several colleagues locally and elsewhere for advice as to how to proceed. I got as many different answers as I made phone calls. One common statement was that my patient had "hashitoxicosis," but one colleague more than disliked that term. All recommended thyroid hormone replacement - already in place. There were mixed opinions about the value of steroid therapy to minimize inflammation. Two colleagues recommended thyroidectomy. One colleague, who also contacted his mentor for further advice, has suggested that further RAI therapy should be considered if the gland is not decreasing in size over the next 3 months. That would be a tough call for me because she would either need pre-RAI thyrogen, a purified form of thyroid-stimulating hormone that is expensive and not always readily available, or discontinuation of her thyroxine till she became hypothyroid.

There is only one good thing about this as yet unresolved clinical problem: this young woman is incredibly cooperative and patient.

If you have encountered this clinical scenario in your practice — many of you must have — please comment on this blog.