What causes the detox bloating?

Just curious, now that I've gone through one hellish cycle of bloating following my first few days of Iodine -- what is the cause of the bloating? From what I've read, it's that the bromide that has been embedded in the thyroid has been shoved out by the Iodine because of their similarity in chemical compound. The bromide is then circulated through the system, but the kidneys can only take so much and the excess stays in the blood stream.

After that, why is their swelling? Is it the white blood cells attacking the foreign body (autoimmune response) that causes inflammation? Or is it something about the bromide that causes water retention?

I THINK it's the former because I sure peed a ton and during this and I didn't see a connection between the amount I peed and when the swelling went down. The swelling just seemed to disappear over time at a gradual pace.

I've got a scientific mind, so I like to know these things even though it doesn't really change anything. :) I figure at some point, someone will ask the same question, so here you go.