There are potentially hundreds of reasons a cat will have seizures from a birth canal injury to poisoning. You have the option of taking your cat to a specialist veterinary clinic for further testing. There is an underlying cause for her seizing and with further, specialized testing it most likely could be diagnosed and treated. As your cat ages, the seizures may increase in frequency or become more severe without treatment. It’s important that, when she does have one, observe her very carefully. Make certain to keep other animals away and provide comfort when they are over.