My 7 year old female cat will not leave the kitchen.?

You should look up Jackson Galaxy or even check him out on Facebook-(he does the show my cat from hell) He's like the cat whisperer. He has seen this behavior before. What he says happens is this-your 7 year old cat was traumatized by the other cat and now it is as if the other cat and her never even knew one another so he suggests re-introducing them with positive reinforcement. Like to feed them together or play with them togehter (maybe about eight feet apart so they can see one another during a positive event) She is feeling insecure. Do you have cat trees in the house? If you could get a cat tree and place near a window-and create sort of a tree dwelling environment for her where she feels safe that will help. For example, a cat tree, next to a high back chair -a few places she can jump up-you have to get her off your counters. Also the other cat may need to have some energy worked off with some play. According to Jackson-when cats act like your kitty is-they have become the "prey" and the two kitties no longer are speaking the same language. They need to re-establish a relationship where they are equals again or respecting each others territory. Jacckson says when cats act like a mouse they are treated like a mouse (by the other cats) because they are hunters-they need to work that hunter energy off-so play with the other cat like 15 mins a day with a toy to wear the kitty out-try to feed them so they are near enough to see but not have a fight-maybe even a baby gate at this point-but please get her out of your kitchen-she needs a safe spot where she can go up high but also walk to litter box without feeling like she will be attacked or cornered in her litter box. Please check out Jackson Galaxy online -hope this helps. Also maybe kitty natural remedies that calm like feliway spray

She just got knocked down the totem poll by the younger cat and now she is at the bottom. She isn't sick and doesn't need to be put down. She is just no longer queen bee and doesn't know how to handle it. Try feeding her seperatly from the other cats and as for the litter box issue, a single cat needs at least 2 litter boxes. Try putting hers somewhere she feels safe at. Shoo the others away from hers. If any attacks happen, stop them. Do things that help move her up in the ranks a bit like let her sit on your lap and play with her. When the others see and try to join in or bully her away, shoo them off and continue with just her. That should help restore some of the balance in your home.

Like I said, there is nothing wrong except that she got knocked down and is at the bottom of the chain now and the others are taking advantage of her and now she doesn't know where she belongs.

Maybe she just does not fit in an environment with more than one cat/pet. Some are just like that. There is a hierarchy thing and if she has lost, she may feel cast out and frightened. However if the Vet wants to see her again, get her there it may be something else get her there.