Radiation poisoning of the thyroid? This is why we must take potassium iodine supplements periodically. It purges contaminated iodine that gets saturated with radioactivity we get exposed to unknowingly. Iodine has been intentionally removed from most generally available salts, and one must actively seek out “iodized salt” to actively add to the diet. [this is the root cause of most thyroid issues in US]. See Brownstein cures.