Our customer wrote:
My cat Tabitha who is 12 years old seems to be in good general health but since we have had to take in a stray female (who we haved tried to home without success) who is larger than her and has been chasing her, Tabitha has times (several days at atime) when she will keep going to her litter box to wee a lot more than she needs to do (often without being able to wee but just squatting) and then also licking her private parts a lot.
You are describing the symptoms of cystitis, which is common in "stressed" cats. It is not dangerous in female cats but is unpleasant - it is very uncomfortable when it happens.
When it occurs, the commonest form of cystitis normally gets better in a few days, just as you describe. Ideally you should try to prevent it happening. Obviously that could involve not keeping the new cat, but that is not proving easy for you. The products Zylkene and Feliway help to reduce stress in cats. One of those, or both together, might make life a bit more harmonious in your household. The cystitis might disappear if your older cat could remain relaxed. The products Cystease and Cystaid are also intended to be used for cats with symptoms like yours. They might well help, but it would mean long-term medication.
Cystitis is always more of a problem in cats if they are tending to produce concentrated urine. Most cats on dried food do this. Therefore it is often recommended to put cats like yours on a wet type diet with only a very few biscuits (to help their teeth). Certainly at the time of a bout of cystitis, it might clear up much more quickly on a wet diet (you can even stir in a little warm water to the food, to make it really moist). Cats with very dilute urine almost never get the stress related "idiopathic" cystitis. Occasionally cystitis in cats is down to a bacterial infection. If it seems to persist longer and to be more troublesome, you should get your cat checked by a vet. A course of antibiotics can help, especially in older cats. It is also important to note that the problem is potentially much more serious in male cats. These have a much narrower urethra. Cystitis in males can go on to produce urethral blockage, preventing them from having passing urine at all. The symptoms of frequent straining with little urine produced are very similar to cystitis, but left untreated this can be very serious. Male cats with symptoms like this which become at all subdued should be taken to the vet as an emergency.