Osteoarthritis in Cats
Dr Cathy Baxter
Osteoarthritis is a problem that commonly occurs in cats, especially in older cats. However, the signs of feline arthritis are often subtle and may sometimes be difficult to detect, even for the most conscientious of cat owners. Consequently, cats with significant arthritis may go undiagnosed for long periods and/or present late (if at all) to the veterinary surgeon, which can further complicate the condition and reduce the probability of success for potential treatments that may be available. Understanding the condition and recognising the signs at an early stage will therefore give your cat the best chance of a successful outcome and reduce the associated pain and other symptoms of arthritis for your cat.
What is arthritis?
Arthritis literally means inflammation of a joint. Joints are complex structures with several individual components, but essentially a joint is formed where two bones moves against each other. Ligaments surround the joint and act like elastic bands holding the joint together so that as the surrounding muscles contract and relax the joint can move without losing its stability. Cartilage covers the bony surfaces of the joint and stops the bones of the joint from rubbing directly against each other during movement allowing the joint to work smoothly and painlessly.
When the cartilage inside a joint becomes damaged, inflammation occurs followed by a series of events that eventually lead to the destruction of the cartilage. Once the joint cartilage is destroyed, the two bones will rub together and the bones of the joint themselves then start to become inflamed and damaged resulting in arthritis.
How common is the problem?
This is very difficult to quantify as (unlike dogs) no formal large-scale studies to determine the frequency with which arthritis occurs have yet been conducted in cats. However, arthritis is thought to affect a significant proportion of senior cats (older than 12 years of age), with research to date showing that the elbows are the most commonly affected joint. The hip and lower spine are also frequently affected and cats with arthritis may have the disease affecting one or more joints (especially if caused by a congenital problem).
What are the risk factors?
There are a number of factors that make feline arthritis more likely to occur. The common ones include:
- Age – arthritis is more common in middle-aged and older cats
- Obesity – cats that are obese (an increasingly common problem in itself) are more likely to be affected by arthritis than a cat of normal body weight
- Previous injury – joints that have been injured in the past are more prone to becoming arthritic later in life
- Congenital abnormalities – those that result in abnormalities within a particular joint can make cats more likely to suffer from arthritis, e.g. hip dysplasia is an example of a congenital abnormality that can lead to arthritis and may affect both hip joints
What are the signs of arthritis in a Cat?
A cat with arthritis may show many different symptoms that are usually gradual in onset and easily missed or misinterpreted even by the most conscientious of owners. Essentially, arthritis causes pain that is exacerbated by movement in the affected joints and the symptoms an arthritic cat displays are a result of that pain. Therefore, any change in your cat’s behaviour may be a result of pain and each cat reacts differently. To further complicate the picture, cats are extremely good at masking pain (an evolutionary advantage to stop weak/sick cats from being predated in the wild).
Examples of the types of symptoms displayed by cats with arthritis include the following:
- Some cats become less active and may sleep more than normal.
- Some cats may become anxious and restless.
- Some cats have difficulty finding a comfortable place to rest or 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 be demonstrate pain when being handled or when undertaking specific activities such as jumping, which they may try to avoid.
- 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, which in turn may result in weight loss.
- Lameness (limping) may be present, but is often difficult or even impossible to detect due to the success or cats for masking their symptoms of their pain.
How is the diagnosis made?
If you suspect that your cat has arthritis, schedule an appointment with your veterinary surgeon who will be able to determine whether your cat has arthritis by performing a physical examination of your cat and by taking x-rays. In some situations, your vet may also want to exclude other causes of arthritis and/or to evaluate fluid taken from an affected joint to help rule out joint infections.
Once arthritis is diagnosed, there are a number of treatment options designed to keep your cat comfortable and pain-free and to prevent progression of the disease.
What treatments are available?
As with people, there is no cure for arthritis in cats. Treatment is aimed towards managing the pain and discomfort associated with the condition and to prevent the condition from becoming worse. If in doubt about whether your cat is in pain, it is advisable to assume that pain is present and act accordingly. There are various treatment options available and in many cases, the different options can be combined using a holistic approach to provide more effective pain relief for an arthritic cat. This approach is usually the safest method of treating feline arthritis and includes:• Control of body weight – this is one of the most important components of treating a cat with arthritis and includes either preventing arthritic cats from becoming overweight or if an arthritic cat is already overweight returning them to an ideal weight. Allowing an arthritic cat to become overweight places additional strain on already painful joints, especially weight-bearing joints such as in the legs. Furthermore, fat cells themselves secrete hormones that contribute to the development of inflammation and pain and further aggravate the condition.
Regulating your cat’s diet and encouraging regular exercise (within any limitations imposed by joint pain) are the best ways to maintain your cat’s body weight. For cats that overeat, accurately measuring and rationing the amount of food given daily will be required. Interactive play with your cat – experiment with different types of toys to find out which toys your cat prefers – can encourage exercise. Food puzzles that require your cat to work to be fed are also a great way to encourage exercise and provide stimulation and enjoyment for your cat. If an arthritic cat is already overweight, your vet can help you plan a successful weight control program for your cat.
- Prescription medications – including buprenorphine, tramadol, Fentanyl®, gabapentin, meloxicam (Metacam®). These are only available on veterinary prescription and require the supervision of a vet for their safe use. If your cat is being treating with Metacam®, it is important to make sure that your cat does not become dehydrated and is not suffering from kidney disease. If your cat begins to vomit, stops eating or develops diarrhoea while taking Metacam®, discontinue the medication and contact your veterinarian immediately.
- Nutriceutical products – including glucosamine, chondroitin and MSM (methylsulfonylmethane). These products are essentially food supplements that can be purchased without prescription and have been shown to have benefit in the treatment of feline arthritis. They are designed to help protect the joint cartilage.
- Alternative therapies – including acupuncture, massage and hydrotherapy. These may be available at your veterinary surgery or your vet can arrange for you to be referred to a feline practitioner.
- Other treatments – including cold laser therapy and stem cell therapy (although these are not widely available in the UK).
- Surgery – may be considered if other therapies have failed and the cat is considered a suitable surgical candidate.
Living with an arthritic cat
Home environment changes may enrich the lives of arthritic cats and provide them with additional comfort and support, e.g. by allowing a cat with arthritis to get up onto a bed or other favourite elevated surface. Also, cats generally like to be up higher where they can safely observe their territory and helping an arthritic cat to access windowsills to watch birds, squirrels or other outdoor activity, helps to provide mental stimulation. Practical measures that may therefore need to be considered when living with an arthritic cat include:
- Pet steps to help cats access elevated surfaces
- Litter trays, food and water should be easily accessible and available in several areas of the house, including each level in multi-level homes
- Low-sided litter boxes
- Extra warmth, e.g. heated/thermal beds
What is the prognosis?
The prognosis varies with the underlying cause of the arthritis and the specific joint(s) affected. In most situations, slow progression of arthritis is expected. However, in many instances veterinary treatments can dramatically improve the function of the affected joint(s) and the animal’s quality of life. Therefore, although arthritis cannot be cured, spotting the signs early and a planned treatment program in partnership with your veterinary surgeon can help make your cat significantly more comfortable and much better able to cope with the condition.