Cat making grinding noises

Question
My 6 year old spayed domestic shorthair female has developed the habit of what sounds like teeth grinding / lip smacking in the last few months and has also developed chronic diarrhea.  Just a few days ago she began to make these grinding noises for several minutes and then vomit.  There was no food in the vomit and it was a very thick and clear viscous fluid, after she had vomited several times I immediately took her to the vet and he kept her overnight for observation and blood work (CBC/GHP), she was given fluid therapy, injections of antibiotics and dex.  He also decided to x-ray her stomach but found nothing unusual. I brought her home and she was fine for one day, no more grinding / lip smacking but today she is back at it minus the vomiting but still has diarrhea.  I was told to give her 1/2 a Pepcid AC 10mg tablet but it has had no effect.  She seems to be fine and is eating normally but the noise she makes is concerning me and she is doing it quite frequently today, It almost seems as if she is grinding / lip smacking in order to make herself vomit.  Please any help would be greatly appreciated.


Answer
Grinding and lip smacking don't make them vomit, but it is a herald of vomiting on its way. The grinding and lip smacking are from extreme nausea. Coupled with chronic diarrhea I would say this cat needs a intestinal biopsy to determine if she has colitis, inflammatory bowel disease or protein-losing enteropathy.

Xrays are not going to show you what a biopsy will. You might need to take her to a specialist or call a near by vet university and see what they can offer.

You might want to try a trial on a hypoallergenic diet first and see if that helps. Hill's prescription diets offers many to help pinpoint a problem like this.

That is about all I can suggest at this point.
I hope you find an answer soon. Please let me know if you do and how she does.