While we are hyperthyroid we are all at risk of having thyroid storm. Basically, this is an extreme medical emergency situation where the thyroid gland suddenly becomes EXTREMELY overactive. We all know how awful we feel when it is just constantly overactive. But with thyroid storm, there is a huge burst of overactivity. And it is life threatening. It is general triggered by infection, trauma, surgery, fear, pregnancy/labor, or other stresses — car accidents, falls, whatever. As the treatments for hyperthyroidism have gotten better, the occurance of thyroid storm has gone down. Generally speaking, someone who is getting adequate treatment for our Graves’ caused hyperthyroidism will not need to worry too much about thyroid storm. It is thought that in general, thyroid storm is a result of untreated or inadequately treated hyperthyroidism. But as long as we continue to be hyperthyroid, there is a risk.
As to why a doctor might worry about thyroid storm, with regard to RAI, then, my guess (and that is what it is — a GUESS) is that it has to do with the fact that we cannot be on antithyroid drugs in the days prior to the RAI treatment. The ATDs block the uptake of iodine into the thyroid. But for RAI to work, the thyroid has to be able to absorb the iodine in the RAI. So we become more hyperthyroid as we approach the day for our RAI treatment. BEING hyperthyroid increases the risks (although they are small) of thyroid storm. A doctor would factor this risk into the medical decision-making processes. For some patients, based on their own, individual situation, a doctor might not be comfortable with that additional risk. For other patients, a doctor might not consider it a real concern.
Bobbi–Asst. Online Facilitator, NGDF