An arthritic cat may show many different symptoms. Essentially, arthritis causes pain. The symptoms that result from arthritis are a result of that pain. Any change in your cat’s behavior may be a result of pain. Each cat reacts to pain in a different manner.
 
These are some examples:
 
Some cats become less active and may sleep more than normal
Other cats may become anxious and restless
Some cats have difficulty finding a comfortable position in which to sleep
Some cats become irritable and begin to avoid contact with family members
Other cats become more social, seeking out more interaction with family members
Cats with arthritis may experience pain when handled
Arthritic cats may have difficulty accessing the litter box and may urinate or defecate outside of the litter box
Some cats with arthritis will stop grooming themselves, resulting in an unkempt coat
The pain resulting from arthritis may cause a decreased appetite for some cats. This in turn may result in weight loss.
Lameness may be present but is often difficult or even impossible to notice. Some cats become good at hiding symptoms of pain.
 
If you think your cat may be experiencing arthritis or if you have questions, please call your vet for further recommendations.
 
Source: Ingersoll Animal Hospital