i am so sorry to hear of this most recent developement ellie. living with someone that is bipolar i can certainly feel your pain.
be thankful that we are in a time that doctors understand much more about the brain and how it works than they did even just 10 years ago. i had a friend whose mother received 18 shock treatments only because she lived in a time that they completely misunderstood bipolar behaivor (this was in the 70's).
my niece, who is now 27, had fits of rage when she was two, she would even foam at the mouth it was so bad. she sounds so amazingly like your daughter it's not even funny. ended up having eating disorders in her early teens and then turned to drugs in her late teens that lasted until her early 20's - all in an attempt to quiet her mind.
why am i telling you all this? be glad you are catching this behaivor early. this is what will save her.