Cat's sudden-onset aggression can be treated

Q: My 14-year-old indoor cat has had sudden episodes of aggressiveness since April. I'll be sitting next to him on the sofa, and suddenly he'll attack with claws and teeth. He even bit me once on the arm. Before these episodes, I am not petting him. When he comes after me, I say loudly, "No, bad cat!" with a cushion in front of me. Then he stops and is OK. Why is this happening? He appears otherwise healthy.

A: Sudden-onset aggression can be caused by both physical and behavioral abnormalities. The best first step is to have your cat examined. Your veterinarian can rule out common metabolic disorders such as hyperthyroidism, which can cause behavior change. Your vet also should examine your cat's eyes to make sure there are no abnormalities, as certain disorders can cause cats to "see things" and act out. Chronic or intermittent pain can cause aggression as well. Your veterinarian may identify other symptoms of pain that your cat is exhibiting that you may not be aware of.

Finally, certain nervous-system disorders, such as epilepsy and brain tumors, can cause aggressive episodes. If your cat is found to be healthy, you will need to address your cat's behavioral issues with an animal behaviorist or veterinarian who specializes in behavioral medicine. Of course, your veterinarian also is an excellent resource for help with behavioral aggression and may be able to help you or refer you to others who can. In some cases, medications such as anti-anxiety or anti-seizure drugs can be used in the short or long term to curb the aggressive episodes. Your veterinarian is the key to finding the cause and appropriate treatment for your beloved cat.

Rachel Boltz, D.V.M., is a feline specialist at Adobe Animal Hospital, www.adobe-animal.com, in Los Altos.

Do you have a medical or behavioral question about your pet? Send your question to Ask the Vet at home@sfchronicle.com.

This article appeared on page E - 6 of the San Francisco Chronicle