Died suddenly

My dog was only 4 years old and very energitic and happy never had and problems and last night I let her out to use the bathroom in my yard on her chain, and when she came back in she was very slow and laid down then started to bleed threw her nose, about 15 mins later she went into a seziure and died. I really dont understand how this could have happend she never had a seziure before, the only thing is she never had a full period but maybe 3 times in her 4 years here I dont know if that means anything but I figured i would let it be know other then that she was a healthy puppy and I just am looking for an possiable answer on how she died...

[Aleda M Cheng, D.V.M., C.V.A]

I am so sorry about your dog!

Highest on my list of possibilities is toxin ingestion, such as rodent poisoning.  Some rodent poisons can cause bleeding out and others can cause seizures.  Another possibility is that she could have an undiagnosed heart condition and the heart just gave out and possibly ruptured, which would cause blood from her nose.

Either way the only definitive way to determine her cause of death would be to have a vet perform a post-mortum and toxicology screen if it is not too late.