Osteoarthritis in cats
U.S. Food and Drug Administration (FDA)
Thanks to cutting-edge veterinary medicine, our pets are living longer. With longer lives, however, come chronic diseases, such as osteoarthritis. Osteoarthritis is a commonly diagnosed disease in dogs. Until recently, it was less commonly diagnosed in cats. Fortunately, more veterinarians now actively look for the disease in cats, especially older cats. By recognizing osteoarthritis in our older cats, veterinarians and pet owners can help these pets live happier, less painful lives.
Osteoarthritis is a degenerative disease in which cartilage — the protective material that cushions a joint between two bones — breaks down over time, causing the bones to rub against each other. This rubbing can permanently damage the joint and cause pain, inflammation, swelling, decreased range of motion, and bony changes in and around the joint. Once osteoarthritis develops, the changes to the joint can’t be reversed. But the disease can be slowed down to help keep the joint working as well as possible for as long as possible.
Recognizing osteoarthritis in cats is difficult for pet owners and even for experienced veterinarians. Cats, unlike most dogs, can tolerate bone and joint problems due to their small size and natural agility and they can hide their pain very well. They also generally dislike being handled during physical examinations. Your veterinarian may have a hard time deciding whether your cat is pulling his foot away due to pain or simply because he doesn’t want to be touched. Cats are notorious for cowering on the exam table and not moving. This is why your observations about your cat’s activity level and behavior at home are important so your veterinarian has the best picture of your cat’s overall health. Your veterinarian may also ask you to complete a special questionnaire that is specific for cat behavior and pain.
Signs of osteoarthritis are more subtle in cats than in dogs. Signs of the disease in cats include weight loss, loss of appetite, decreased activity level, change in attitude (grumpier or quieter than usual, for example), decreased grooming, urinating or defecating outside the litter pan, and not being able to jump as easily as before. Surprisingly, lameness (limping) is not as commonly reported by owners. In a study of 28 cats with osteoarthritis, less than half limped, but almost three-quarters didn’t want to jump, and two-thirds jumped a shorter distance.
The most common joints to develop osteoarthritis in cats are the elbows and hips, although shoulders, hocks (ankles), and knees can also develop the disease. Arthritis in the backbone and sternum (the chest bone where the ribs attach) is also common.
Researchers have studied changes in the X-rays of cats with osteoarthritis. In general, X-ray changes in cats are less severe than in dogs with osteoarthritis. Sometimes, surprisingly, cats with osteoarthritis have no changes on their X-rays.
One study looked at X-ray and physical exam findings in 13 cats with osteoarthritis. Researchers physically examined the cats’ joints for signs of pain and then looked for signs of osteoarthritis on the cats’ X-rays. Half of the cats’ joints had osteoarthritis. Only 10% of the joints, however, were painful and also had changes on the X-rays. This finding indicates that in cats, painful joints don’t necessarily mean there will be corresponding joint changes on X-rays.
Treatment options for cats with osteoarthritis are limited. Non-drug options include weight loss for overweight cats, increased exercise, or physical rehabilitation (for example, muscle stretches, swimming or hydrotherapy, or shock wave therapy) and changes to the environment, like using litter pans with lower sides for ease of entering and exiting, raising food and water bowls, providing ramps and steps for getting to high places, and using soft bedding. Many veterinary nonsteroidal anti-inflammatory drugs (NSAIDs) are approved for long-term use in dogs to control pain and inflammation from osteoarthritis. But unfortunately, no veterinary NSAIDs are currently approved for safe, long-term control of pain and inflammation due to osteoarthritis in cats. Cats are especially sensitive to the side effects of NSAIDs. More information about veterinary NSAIDs can be found in the article, Get the Facts about Pain Relievers for Pets, at https://www.fda.gov/animal-veterinary/animal-health-literacy/get-facts-about-pain-relievers-pets. Solensia is a monoclonal antibody injection that is approved to treat pain caused by osteoarthritis in cats. It works by decreasing the pain signals associated with osteoarthritis.
Conclusion
Osteoarthritis in cats is difficult to recognize. By knowing what signs to look for at home, you can give your veterinarian important clues about your cat’s health. This information, plus physical exam and X-ray findings and special cat pain and behavior questionnaires, can help veterinarians better diagnose the disease and more readily ease the silent suffering of many older cats.