What is the likely cause of a dog's sudden death?

[TikiMom]

Our 14 year old whippet was in pretty good health. He had some decline in hearing and sight and mild arthritis but still had normal appetite and acted normally. The only real problem we noticed was he couldn't hold his urine all night and had to be let out at 2 to 3 am most nights. He had regular checkups and the vet did diagnose him with a heart murmur but it did not seem to affect him.
Yesterday I came home for lunch and he got up to greet me as he always did. But he only made it a few steps before his legs started flailing around on the floor and he fell over. His tongue fell out of his mouth, his eyes were open and fixed, his urine pooled under him and he was gone just like that in a matter of moments.
Was that a stroke or a heart attack or a seizure? I know he was old but without any real signs of failing health do older dogs just die without warning like that?
Our kids are all heartbroken and I wish I had better answers for them.

[soclar]

Hi there,

My 15 yr old westie just passed away in a very simular way yesterday too! Our vet couldn't identify what was the exact cause of his death.. I was wondering would it be the red eared slider turtle that I had just started to take care of for my friend on vacation one week agoe that passed some kind of disease to him? I know turtles sometimes carry salmonella and pass that to human but couldn't find any related topic for dogs.. hope that's not the reason my dog passed away..

[Jaybay]

I am so sorry you lost your friend so suddenly.  Everything you mentioned is within the realm of possibility, but without a post-mortem (autopsy) there is no way of knowing exactly what happened.  

You did a great job with your dog in that he lived for 14 years and was in good health.  The same things that cause sudden death in humans happen to dogs as well.  So the answer to you question is yes, dogs can die suddenly with no symptoms that anything is wrong.  As traumatic as it is to those of us left behind, it was a kindness that he never had to suffer and likely didn't even know anything was wrong.  Sometimes there just aren't any good answers.  :-(