Aloha! You're speaking with Dr. Michael Salkin
I'm sorry that your question wasn't answered in a timely manner. Unfortunately, drooling and polydipsia (increased thirst) - while important symptoms - aren't pathognomonic (specifically indicative) of any one disorder. Drooling suggests oral trauma or gastrointestinal distress/nausea. Polydipsia suggests a profoundly dehydrated cat. If she isn't losing fluids through vomitus or diarrhea, there are quite a few conditions to consider...
1) Bleeding internally such as would be seen with anticoagulant rodenticide ingestion - often by ingesting a rodent whom was poisoned. Please check her gums and tongue. If not nicely pink but whitish instead, she has become profoundly anemic due to internal bleeding.
2) Urinary tract infection involving the kidneys
3) Both kidney or liver insufficiency
- uterine infection in an intact cat.
mellitus, diabetes insipidus, Addison's disease - all rare in a 2 year old
6) Miscellaneous electrolyte - calcium, sodium, potassium - imbalances - rare.
Please check her color for me, pick up her skin between her shoulder blades and see if it returns to normal quickly or not (if not, she's dehydrated), and please check her respiratory rate at rest. She should be taking less than 40 breaths/minute.