my dog ripped up our carpet

Question
I have a female shepherd keshound mix, fixed. She is 11 and will be 12 around may.  She weighs about 57lbs, and looks more like a short shepherd with an undercoat the a keshound.  She is the great dog in the world and was always easy to train.  We followed a friends advice who had many dogs a crate trained her.  She gets walked twice a day and feed once in the evening.  She always has fresh water.  We are bad and spoiler her allot with table food.  I know we shouldn't but shes so good you can't help it.  Any way the past 2 days we were out this weekend, she ripped up the carpet by our entrance to our garage on our lower level.  To the point where her paws have hit the tacking multiple time and there are stains from her bleeding.  We don't know if something may have gotten in the garage like a field mouse so we set traps, but no results yet.  She has great hearing and advise us of such things before.  The only other time this happened is when she was locked up in the play room due to a new cleaning person.  And my wife forgot to let her out that morning, she rip up the rug trying to get out to go the the bathroom, which she eventually did in the room.  But that was not the case this time.  There were no accidents any where in the house.  We are at a loss what to do.  Is this something we can train her not to do?  Can we expect more of this?  What would be the cause of this age? bread? etc?
Thanks in advance for all your help.

Answer
Without a full behavioral consultation, I'm not sure, but one possibility is that her age is affecting her confidence and she is anxious when you leave her alone.  Have the vet check her vision and hearing even though she always had good hearing before.  Also, if it turns out that there's no physical problem, consider that she may still be anxious for some reason when you leave.  You can set up a video camera to see how she behaves.  If she is anxious right after you leave, it may be separation anxiety.  If she is anxious hours later, it could be that she is trying to get to the "potty" area.  If she is shredding her paws, my bet is on separation anxiety.  There's a good book on the subject by Patricia McConnell - "I'll Be Home Soon".  Grab a copy and see if the description fits your dog.  There are lots of good hints in the book on how to deal with it.