My 11-year-old cat is suddenly vicious. Is it related to grief?

Older cats can sometimes start to show signs of dementia, but usually these cats tend to wander, get 'lost' in the house or vocalize for no obvious reason. There are some other medical conditions that could cause a change in behavior including hyperthyroidism (overactive thyroid gland) or possibly pain from arthritis or another condition. I'd recommend making an appointment with your veterinarian for an exam and potentially testing like blood work to make sure there isn't a medical reason for the biting.

If this is a recent change in behavior I'd recommend having your veterinarian perform a thorough physical examination as a first step. Some common diseases in older cats like hyperthyroidism can make them much grumpier than usual. Pain from arthritis can also make cats react in an aggressive way. If your veterinarian feels there is no medical reason for the behavior change I would then recommend talking to a feline behavior specialist to see if there are changes you can make at home to address this behavior. Cat bites are no joke - veterinarians have lost fingers due to infected cat bites and cellulitis! But it sounds like there could be some other things to look into before deciding on euthanasia.

Sometimes this type of behavior that comes on suddenly can be due to an underlying medical condition such as hyperthyroidism. Your veterinarian can test Tabs blood to see if his thyroid levels are high and if so, recommend appropriate treatment.

Sorry you are having some troubles with Monster! I recommend that you take him to your vet for a senior blood panel. They can check his thyroid as well. Hyperthyroidism (an overactive thyroid gland) is not uncommon in older cats and can lead to behavioral changes, more vocalization, eating more, acting odd. Get him in for bloodwork when you can! Thanks for asking Petco Pet Education Center, formerly Petcoach!

I would have Nurmal (love her name!) checked out by a vet. Sudden changes in behavior in a senior cat can point to medical problems such as hyperthyroidism and arthritis (pain may make her cranky). I recommend getting a physical exam, geriatric blood panel, and urinalysis. These tests will help the vet identify if she is suffering from a medical illness. Should one be found, the vet can discuss treatment options with you. I would take her into the vet on Monday if possible. Good luck, I hope this helps!

Since it sounds like this is a recent behavior change for Zora, I would be very suspicious that she may have an underlying medical problem causing her aggressive behavior. There are a number of common problems in older cats that can cause behavior changes like this, including hyperthyroidism, chronic kidney disease, or even pain from arthritis. I would recommend taking Zora to the vet for an exam when you are able to - he/she can do blood work if needed to check for these issues. If a problem is found, it's likely that it can be treated with medication to make her more comfortable and hopefully improve her mood as well :)

These sudden changes in temperament and the weight loss are commonly due to an endocrine problem called hyperthyroidism. The thyroid starts working more than normal increasing the metabolism (that is the cause of the weight loss) and causing behavioural changes similar to what you described. A clinical examination at your local veterinarian is essential to confirm this clinical suspicion and treat appropriately. A blood test and urine analysis are needed. Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further. If this answer was helpful please let us know, this will be used to improve our service!