Hello fellow cat lovers! I’ve had cats my entire life. My first cat, who I begged and begged to get, was named Suzy; we adopted her from the local shelter. At one point, after I finished all of my veterinary training, my family had four cats (plus two dogs and three fish tanks). One of my cats, “Fat Daisy,” was very obese, had trouble walking and actually ruptured her cruciate ligament in her left knee; you know, a “football injury.” She had surgery, but was never quite the same. She would stumble and never jumped onto chairs or beds or sofas. I attributed her lameness and unwillingness to jump to her being pretty overweight.
After months of dieting, her weight improved, but her lameness worsened. I had the surgeon who repaired her knee evaluate her. He ordered a set of X-rays of the repaired knee, along with her hips, elbows and shoulders. To my surprise, he told me the problem wasn’t the knee; that was stable. But he did tell me she had DJD. DJD is an acronym for degenerative joint disease, or arthritis. Additional weight loss, along with anti-inflammatory medicine and dietary supplements, was recommended. Fat Daisy did improve, but managing her lameness, pain and weight were challenging.
I had little training 20 years ago in veterinary school on arthritis in cats. We learned all about it in dogs, with just a mention here or there about arthritis in cats. Over the past decade, arthritis, or degenerative joint disease (DJD), has become a very important topic in feline medicine.
Arthritis literally means inflammation of the joints, and many things can cause it. It can be primary, meaning it appears not to be caused secondarily to disease or an underlying injury. Arthritis can also be secondary, due to a previous injury, excessive force on a joint (obesity), incongruity of the joint or from an infection of the joint or inflammation caused by immune-mediated diseases. For example, I expected Fat Daisy would have had some arthritic changes in the knee that was repaired. The torn ligament caused instability in her knee joint and the instability led to inflammation, which then caused arthritic changes.
More Common Than You Think
DJD in cats is usually primary, with no underlying cause. It is more common in adult and senior cats (especially those over the age of 12). In one study, 65 percent of cats 12 years old or older had evidence of DJD. Depending on their age and reasons for being seen by a vet, the incidence of DJD in adult and senior cats ranges from 20 to 90 percent!
Unlike Fat Daisy, most cats with arthritis are not lame or limping, because the majority of cases involve the same joint of both legs (for example both elbows having DJD). It’s more difficult to identify DJD if multiple joints are affected with arthritis. The cat limps on both legs instead of just one, which is tricky to see. Less than 20 percent of cats with DJD have noticeable lameness.
Signs Of Cat Arthritis
Most cats with arthritis exhibit behavior and lifestyle changes. Anxiety and aggression are the most common symptoms in cats with arthritis. Additionally, lethargy/sleepiness and more vocalizations occur, along with changes in grooming behavior. Some cats will excessively groom and some will stop grooming themselves altogether, causing a matted, unkempt coat.
These are not signs most people would associate with a painful joint. Most pet owners, when noting some of these signs, attribute them to increasing age. A common statement heard in practice is, “Yes, she’s getting more ornery as she gets older.” Hissing, swatting and reluctance to be petted are some signs of aggression to watch for. Decreased jumping ability, unwillingness to jump, and a stiff walk are other signs that are more frequently associated with arthritis.
Methods Of Diagnosis
One of the most difficult parts of an examination performed by veterinarians is an orthopedic exam on a cat. See for yourself; try to hold your cat’s paw and bend the elbow — I’m warning you now of getting scratched or bitten. It’s also very difficult to observe a cat walking or trotting in the exam room. Most cats aren’t used to walking using a leash or harness, and they’ll usually find a spot under the counter or a chair to hide instead of walking around. So, vets rely a lot on what owners tell us.
The veterinary school at North Carolina State University developed a pet owner questionnaire called the Feline Musculoskeletal Pain Index that has been shown to be accurate in assisting with the diagnosis and response to treatment of cats with arthritis. If pain is found during the orthopedic exam or there are symptoms compatible with DJD, then radiographs (X-rays) are performed.
As arthritis progresses, it’s more likely that the radiographs will note changes. However, inflamed joints may appear normal on an X-ray. Also, the changes noted with arthritis don’t equate with the symptoms. Arthritic joints with cartilage loss, fluid buildup and boney proliferation may not be very painful, but these can look horrible on the X-ray. At specialty veterinary centers and teaching hospitals, more advanced testing like CAT scans (no pun intended), magnetic resonance imaging (MRIs) and force-plate analysis can be used to help diagnose DJD.
A variety of treatments are available, and each case needs assessment for which options are best. The list below focuses on cats with primary DJD; cats who have secondary DJD may need surgery or treatment for other ailments that caused the arthritis.
1. Environment: Assist your cat by modifying your home. Water and food bowls, litter boxes and toys should be easily accessible. For example, put everything on the ground floor so your cat doesn’t need to climb up and down stairs, use pet ramps to make it easier for your cat to reach her favorite windowsill or sofa. Get her a soft, comfortable pet bed.
2. Weight Reduction: If your cat could have the adjective “fat” in front of her name, like my Fat Daisy, weight reduction is very important. Talk to your veterinarian about a diet change, but never, ever withhold food from a cat. While starvation diets may work for movie stars, they make cats very sick with fatty liver syndrome. Your veterinarian will assess the body condition score of your cat and then formulate a weight reduction plan.
3. Food Additives: No doubt you’ve seen infomercials about glucosamine for human joint health. Quite a few studies examining additives such as Omega-3 fatty acids (EPA and DHA) have noted improvement in activity and jumping ability of cats with arthritis. Other additives, called chondroprotectants, such as glucosamine, chondroitin and green-lipped mussel extract, may also help, but these have not undergone as much research as Omega-3 fatty acid supplementation.
4. Anti-Inflammatory Drugs (NSAIDs): These are the most common medications used for joint pain caused by arthritis. They work by blocking inflammatory molecules, primarily cyclooxygenase or COX. Many products are available, such as meloxicam, carprofen and ketoprofen. They appear to be equally effective. Currently, only meloxicam has been FDA-approved for use in cats and is the drug with the most research behind it. NSAIDs can cause kidney problems, stomach ulcers and affect the heart. Of greatest concern is the effect on kidney function. Your veterinarian will devise a plan of dosing, rechecks and monitoring the kidneys if an NSAID is chosen as a treatment.
5. Opiods: These are medications that help control pain by blocking pain pathways and binding to enkephalin receptors in the brain, creating a euphoric feeling. These are controlled substances and can be used in addition to NSAIDs or if your cat cannot take NSAIDs. Buprenorphine is one of the more popular opiods for cats. It’s a liquid and is absorbed by the gums, so it’s not swallowed.
6. Acupuncture And Physical Therapy: There is limited research to the benefit of physical therapy (massage, non-impact walking, range-of-motion exercises) for cats, but those modalities are safe and can definitely help dogs. Acupuncture has been around for centuries. Again, there is not too much research for its use in cats with arthritis. In my opinion, it may help and is unlikely to cause harm.
7. Stem Cell Therapy: The idea behind stem cell therapy is to help rebuild damaged joints and to decrease the inflammation inside the joint. Studies in dogs have shown promise, but more research is needed to see if the same is true for cats.
I hope you are now well informed about arthritis in adult cats and realize that if your older, adult cat is lying around more, not jumping onto and off things, has a change in appetite or seems more aggressive, it may be arthritis.