My 10-year-old cat is hiding, not eating, and being aggressive. Why?

I am very sorry to hear about Skylee. Unfortunately in an older cat there are a large number of conditions which could cause lethargy, nausea, and anorexia. I would strongly recommend taking him in to see the veterinarian as soon as possible. A good physical examination may help them get a better idea of possible causes. Most likely they will want to do bloodwork to check for signs of kidney disease, liver disease, infection, or anemia. They may recommend x-rays depending on his examination and history. It is best to have older pets acting ill in this way checked out soon so that if there is a serious disease we can start treatment as quickly as possible.

It certainly sounds as though Grey is not feeling well! Inappetance, hiding and vocalization can indicate a number of underlying conditions, but hyperthyroidism is at the top of the list. I recommend taking Grey to her vet for an exam and lab testing (CBC, chemistry, T4/thyroid hormone, urinalysis) to get to the bottom of things. Cats can develop hepatic lipidosis (fatty liver disease) when the stop eating, so her condition is fairly urgent.

It sounds like he should be examined by a vet to rule out a medical problem. He could have an infection, parasite, metabolic, and/or endocrine disease and your vet can run blood work to help diagnose and the determine if treatment is needed. Hope he feels better soon!

This is very serious. Cats often hide when they are ill. Bob needs to see a vet as soon as possible. You did not mention his age so it's difficult to give you an idea of what may be going on. If he is a young cat then he may have an intestinal obstruction. In an older cat the most likely causes for vomiting, hiding, weight loss and "bathroom" issues are: kidney disease, thyroid disease, diabetes and cancer. Regardless, he needs to see a vet. You can't let him go on suffering.

Older cats are prone to many diseases, including kidney disease, hyperthyroidism, diabetes, infections, cancer, etc. He should be examined by a vet for a work-up with blood-work and a urinalysis to help diagnose and then determine the best way to treat and manage his problems.

If Major had not been urinating or had been in and out of the litter box a lot then it’s possible he could have a urinating blockage which is an emergency. If he is urinating normally but not eating I would still recommend a vet visit tomorrow. Hiding is something cats do when sick. There are any number of things that could have an older cat not feeling well including dental disease, renal disease or other organ dysfunction. I hope Major is better soon. Thanks for using Petco Pet Education Center, formerly Petcoach

Any cat that is hiding and not eating is sick. She needs to see a vet ASAP. When cats don't eat for about 3 days their liver starts to mobilize fats for energy and this causes fatty liver disease. So, she may get fatty liver disease on top of already having another illness which will make her prognosis even worse. Please get her to a vet ASAP.