Sudden Seizure

I’m sorry in advance if this is upsetting to anyone reading, but I am looking for some possible answers. Two nights ago my 2 year old dog suddenly passed away. He was playing in the yard for a few minutes and then walked up our porch stairs and stood next to me for a few minutes. Suddenly he collapsed and stared having a seizure. Immediately after he wasn’t breathing and despite trying to do some sort of compressions or rescue breaths he was gone within seconds. When we brought him to the vet right after, we didn’t get to speak with a doctor at all and got no real possible explanations. So, that is what I’m looking for from anyone. I don’t expect a diagnosis, all I want to know is what could have happened so fast, just some possibilities would help me comprehend the whole situation. Thank you.

I'm so sorry that this happened to you and your dog.  Two years old is very young and it sounds extremely traumatic to have witnessed.  It's probably of little comfort, but when dogs have a seizure, we think that they know nothing of what is happening to them (I assume that this comes from humans in the same situation) and I expect that they don't process any pain. The first question is, whether or not it was a seizure.  Here is a good article about how to identify one:  https://vethelpdirect.com/vetblog/2021/02/28/how-do-i-know-if-my-dog-is-having-a-seizure/ as there are other things, for example low blood glucose, which look similar.  Low blood glucose would be obvious; the pet is revenously hungry beforehand and further more, it is most common in very young dogs. You kindly stated very clearly your understanding that you cannot expect a diagnosis, so here is an article which discusses carious possibilities  https://vethelpdirect.com/vetblog/2020/08/13/seizures-in-an-older-dog/ I hope that this helps

It is also worth saying that two years old is not, by any means, too young for 'true' epilepsy to start.  All the best to you and we're here if you have any questions

I've been asked to qualify my last comment:  'true' epilepsy starts most commonly between the ages of 1 and 3 so this is certainly a possibity