Seizure and death in rabbits

Question
Hi, this isn't priority, I'm just curious. My rabbit died on Sunday morning. On the Saturday I gave her and my guinea pig a fresh treat on Saturday morning like I always do. That day it happened to be spinach which they love. On Saturday afternoon I decided to treat them to a little more but when i got to the cage my rabbit was having a fit of some sort. She was sitting back on her haunches but she kept leaning to one side and pushing her head back. Her nose was twitching furiously and it seemed like she was gnawing frantically with her teeth. I noticed they hadn't eaten all the spinach which i thought was strange because they generally devour anything fresh and leafy that I give them. I took her out and tried to hold her but the fits continued right through the evening. Her eyes were unresponsive between the fits and her pupils looked like they were enlarged but then it wasn't very bright where i was sitting either. Later in the night after each fit she began running and bouncing crazily before I could catch her. Her nose and mouth went bright red but I'm not sure if this was from grinding her teeth the way she was. By Sunday morning she had died. My guinea pig is still perfectly healthy although lonely. I live in South Africa so we moved the cage and cleaned thoroughly around it in case of snakes but found nothing. I don't know what else it could have been and I'm worried because i don't want my guinea pig to die such a tortured death. I couldn't afford an autopsy either. Any clues or suggestions you might have to helping me understand would be great. I also have two cats and don't want them dyeing this way, especially if it is some sort of poison. There was no point or anything in the cage, the only thing she had chewed on was a plastic margarine container that the kids left in her cage. Didn't take it out because she would bite it and drag it around so I thought she was playing, the guinea pig isn't one for games so I thought she was entertaining herself. BTW, my cats wouldn't have terrified her into getting fits, they actually brought her in as a baby, no idea where they found her but she was unhurt and has since then had no fear of the cats.
Thanks for your time :)  

Answer
Dear Melissa,

I am sorry about the loss of your bunny.

Sadly, there is absolutely no way to confidently ascertain a cause of death without a post-mortem exam, preferably including histopathology of major organ tissues.  The signs you describe are somewhat vague, and could have been due to any of dozens of different things.

Please read:

www.bio.miami.edu/hare/sickbun.html

which might give some clues.  It almost sounds as if she aspirated (inhaled) something, and was having trouble breathing.  But as you know, only a necropsy would reveal the actual cause of death.  Getting her to a vet immediately when you started to see the strange behaviors might have saved her life.

Unless you can provide a lot more specific information, this is the best I can offer.  

If the body has been kept very cold (not frozen), and it has been less than 24 hours since death, a necropsy may still be possible, if you feel that would give you closure and peace of mind.  You can find an experienced rabbit vet here:

www.rabbit.org/vets

to call and find out what your options might be.

I am sorry for your loss.

Sincerely,

Dana