A 7-month-old British shorthair. A Fredericksburg, Va., reader’s rescue cat has been attacking her owners. (GlobalP/Getty Images/iStockphoto)

Dear Dr. Fox:

Thirteen years ago, we rescued a young female cat who had apparently been dumped. She was in poor shape, starving and full of fleas.

We took her to a vet for complete care and spaying. The vet thought the cat's mother may have been malnourished when pregnant with her.

At home, we fed her well, but she remained obsessed with food, especially fats. She would watch as we unpacked groceries, and steal away with butter or cheese and eat it. At the same time, she was given to sudden bursts of violent behavior, as though having flashbacks. We assumed she had been abused.

Without warning, her pupils would dilate and she would launch herself at one of us, often aiming for the face. I warded her off many times by holding a pillow at arm's length, which she ended up clinging to. Legs were a target, also. Seven months after taking her in, we reluctantly had her declawed.

Gradually, she became socialized and settled into being a sweet kitty, and remained so for years. However, now she is reverting to violence. There are still no children or other animals indoors, or even nearby, to trigger aggression. All will seem well, and then suddenly she attacks and bites, drawing blood and, in one case, causing an infected wound. The attacks are increasing.

We are at a loss to explain this reversion to hostile behavior and don't know how to handle the situation. Any guidance you can provide would be greatly appreciated.

C.K., Fredericksburg, Va.

DF: The saga of your poor cat, and you, is indeed distressing. You did follow my first principle of responsible companion animal care: Any time there is a change in behavior, consult with your veterinarian.

It is regrettable, but understandable, that the only treatment was to remove your cat's claws. This can make cats feel more vulnerable, and then they are more likely to bite.

I agree with you that her sudden aggressive behavior when you first adopted her was possibly related to earlier traumatic experiences, a case of post-traumatic stress disorder, indeed. But where there is sudden and unpredictable aggression with biting, in a cat or any animal brought into the home that has been outdoors, possible contact with a rabid animal must be considered. Certainly the attending veterinarian would have ruled out this possibility when you took your cat in for treatment after rescuing her.

The craving for fat is very curious. Cats do need animal fats that contain omega-3 fatty acids, and many cat foods, especially dry kibble, are deficient. They are essential for several organ and system functions, including the brain.

I would give her a sardine or two a day (canned, in water), for a start. Also, because some dogs with low levels of brain serotonin can have attacks of psychotic rage, a supplement such as PetzLife's @-Eaze to elevate your cat's serotonin might also help.

Odors can sometimes trigger cats to attack. One woman was cornered in her bathroom by her Siamese cat after she put on a new perfume. Perhaps you have a new deodorant or other toiletry product with a scent that disturbs your cat. A room diffuser dispensing organic essential oil of lavender might help calm all of you. Fresh or dried organic catnip has a tranquilizing effect on some cats, and your cat might enjoy a pinch in the early evening.

It's possible her thyroid gland is hyperactive, which can also account for sudden aggression. This should be checked. If that is not the issue, and sardines and other suggestions do not help her enjoy a normal life without having these almost seizurelike episodes, discuss trying psychotropic medication with your veterinarian to reduce anxiety and possible brain seizure activity. Older cats do develop dementia, and chronically painful conditions such as arthritis can bring on aggression, but rarely to the intensity shown by your cat.

Dear Dr. Fox:

Our 50-pound dog, Mo, about 10 years old, had a vestibular incident early in the morning 18 days ago.

He had all the major symptoms — sudden onset of loss of balance, disorientation, head tilt and irregular jerking eye movements — and he also threw up three times. I understand it is like vertigo for dogs, especially old ones.

We rushed Mo to an emergency clinic, where he was given medication for the upset stomach, meclizine for the dizziness and IV fluids. The next day, our regular veterinarian also prescribed Zeniquin, just in case he still had an ear infection. (Mo had had an ear infection several weeks before the incident and was treated with Gentizol, which I have since read can contribute to vestibular incidents.)

Before the incident, we knew there was something brewing, because Mo started having accidents in the kitchen, which he had never done before. Blood and urine tests indicated he was in great shape, but the incident let us know that there was a definite problem.

Mo is doing much better now. He still has his head tilt, but his big problem is at bedtime, when he gets very restless and appears disoriented. We have added night lights, and our vet prescribed trazodone to help calm him down, but it hasn't worked. He has also started having accidents in the kitchen during the night again. I finally tried Dramamine last night, and he was able to sleep for six hours. However, when he woke up at 4 a.m., he was restless again and started roaming the house and whining.

Do you have any suggestions to help us get through the night? My wife and I are getting large bags under our eyes and feel really bad that our best friend is uncomfortable.

P.N., St. Louis

DF: You give a very clear description of this old-dog middle-ear condition, which is relatively common and usually associated with an earlier ear infection. It can sometimes be prevented with optimal nutrition.

He now seems to be showing signs of anxiety, which could have been triggered by the intense vertigo and nausea that this condition brought on. Because the trazodone has not helped, discuss increasing the dose with your veterinarian, or try Valium.

He might be also be showing early signs of dementia or cognitive dysfunction, which you should raise as a possibility with the attending veterinarian. Supplements such as fish oil and coconut oil have multiple benefits for older dogs. Also try 3 to 6 milligrams of melatonin at bedtime. Another treatment worth trying is the prescription medication selegiline (1 mg/kg).

Many older dogs become restless because of the constant pain of arthritis. Others become anxious because they need to be taken out more often to urinate, as a result of drinking more water because of kidney disease. Both of these common old-animal issues need to be considered. Slippery floors can also be bad for older dogs, so you might need new, secure carpets.

My book "The Healing Touch for Dogs" will give you advice on how to help him relax and feel secure while enjoying the therapeutic benefits of a full-body massage.

Michael W. Fox, author of a newsletter and books on animal care, welfare and rights, is a veterinarian with doctoral degrees in medicine and animal behavior. Send letters to Dr. Michael Fox in care of Andrews McMeel Syndication, 1130 Walnut St., Kansas City, Mo. 64106

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