Guniea Pig died

Question
Hi Nicole,

For the past month we have been looking after a relative's guinea pig. She has been fine for the whole time adjusting well to staying with us, eating, drinking and pooping regularly. And she has been quite energetic running around the living room if we let her out.
Then this past week we have noticed she was a little bit thinner, but she was still eating her food so we did not think much of it. I changed her hay to a new type of hay this Friday, and she seemed normal after that, perhaps a little calmer on saturday than normal but she was still eating and drinking. And then yeaterday (Sunday) when we got home in the evening we took her out of her cage and she had diarrhea and seemed very lethargic. We put her down and she would just stand on that space or if she tried moving her backpart would just be flopping back and forth like she had no control over it. She also seemed colder.
We couldn't take her to the vet because nowhere was open but we put her on a blanket on top of a hot water bottle so she would keep warm. Everytime we tried to put her back in her cage though she would just creep to a corner with her face out the sprinkles.
We tried to make her drink more because of the diarrhea/dehydration, but then suddenly she just flopped over and had gasping fits for a few minutes before dying.

We just can't understand why she died and why it was so quick?
We just hope it was not because of anything we did.
Hope you can shed some light on it.

Thanks,
Line

Answer
Hi Line,

    Labored breathing, loss of appetite, and lethargy are all signs of an upper respiratory infection (URI).  If not treated immediately, URI is fatal in most cases.  However, it also sounds like it could have been dehydration.  Dehydration, whether from diarrhea or any other reason, is also fatal in most cases.  Too much lettuce is one cause of diarrhea.

    Other than those suggestions, I'm not too sure what could have happened.  Guinea pigs are known for dying very mysteriously and without much of a warning at times.  I am very, very sorry that happened =(

                                                - Nicole