Cat behaviour changed after outdoor attack

Question
Two days ago our indoor cat escaped to outside at night.  We caught her with in 10 minutes but did hear what one might think was a cat fight before we did.  We had a terrible time trying to get her back in the house.  I had to use the blanket from her bed to cover her and carry her in or I would have been injured by her teeth and claws. Before this episode she was loving and gentle.  Now she is freaky...she is constantly growling and hissing at us hiding under the couch and jumping out aggressively at us.  The only time she is nice is when she wants to be fed.  Is she just scared. I can see no injuries as I was able to examine her in one of her calm moments before I fed her.  She is fixed, and did come to us when we originally called her but went to our neighbors door instead of ours which is why we had to do what we did.  Can you help and give me an idea, we are just trying to leave her alone to settle down..she is 12 years old and only goes outside on a harness and has never been outside at night.

Answer
Hi Sharon,

I'm so sorry to hear about that.  Well, the first thing you need to do is take her to a vet to rule out any potential injuries.  If she was in a fight, she was probably bit, which is painful and would cause her to act in this manner.  Not only that, but some cat diseases are transmitted through bites, so you will need to have her tested for that.  Yes, even if she has been vaccinated not only because vaccines are NOT 100% effective, but because there is no vaccine for FIV.  There's no way for you to know if she's actually injured if she's acting the way you say and you can't get close to her to do a thorough exam.

Secondly, yes, she is going to be freaked out and upset as she was in an unexpected cat fight, especially at her age.  So while she does need time to calm down and settle back into a routine, it is more likely that she is in pain to some degree.  Please take her to see a vet, make sure whatever injuries she has are minor and are addressed and cleaned, and that you have a viral load test done with some blood work.  Best of luck!

Best regards,

Holly Martin
Cat Care & Behavior Specialist
Texas A&M University
B.S. Animal Science