osteoarthritis and rheumatoid arthritis in pets
Just like humans, dogs and cats get arthritis. We’ve touched numerous times on osteoarthritis (or degenerative joint disease) in both dogs and cats, covering what it entails, why it happens, and how it is treated.
What is osteoarthritis?
Osteoarthritis is a chronic, irreversible disease of the joints. It can happen any place that two or more bones meet. In a normal joint, cartilage covers the bones where two bones meet. Osteoarthritis occurs when there is damage to the cartilage, either from a traumatic event, or from normal wear and tear. Athletic and obese pets tend to have more wear and tear on their joints, and thus are more prone to developing osteoarthritis.
Osteoarthritis can occur in just one joint, or in multiple joints. Commonly affected joints are the hips, shoulders, elbows, knees, and the joints of the spine.
Today I’d like to introduce you to a completely different kind of arthritis—rheumatoid arthritis. Rheumatoid arthritis is an inflammatory joint disease that is immune-mediated. While we don’t fully understand what triggers the disease, we do know that antibodies produced by the body form complexes in the joints that lead to inflammation. Progressive changes in the joints lead to the erosion of cartilage and the underlying bones in the joint. After a time, the surface of the bone can collapse on itself, further destabilizing the joint.
Because rheumatoid arthritis is a systemic rather than local problem, it causes arthritis in multiple joints when it occurs. Early clinical signs include shifting leg lameness, as different joints may feel sore on different days. Rheumatoid arthritis can also cause fever and slightly enlarged lymph nodes, which in turn can cause lethargy and inappetence. Affected joints are painful and swollen.
Rheumatoid arthritis can occur between the ages of 1 and 9 years old, though the average age is about 4 or 5 years old. Small and toy breed dogs are affected more often than large dogs, but any dog can develop rheumatoid arthritis.
Many dogs can be diagnosed with rheumatoid arthritis via a blood test. Rheumatoid factors are present in many dogs with rheumatoid arthritis and can be detected with specialized blood work. However, 30% of dogs do not test positive because rheumatoid factor levels can wax and wane, so it may be helpful to retest these dogs in one or two weeks.
In dogs with negative blood work, clinical signs together with bony changes present on x-rays can lead a veterinarian towards a diagnosis of rheumatoid arthritis.
Treatment of rheumatoid arthritis is very similar to treatment of osteoarthritis. Both conditions are chronic and will require lifelong treatment. Keeping affected animals at a trim weight will do wonders to reduce wear and tear on joints, and thus give these pets a better quality of life. Pain is managed through the use of non-steroidal anti-inflammatories (NSAIDs) and other stronger medications if needed. Chondroprotectants, like injectable Adequan and oral glucosamine may also help clinical signs. Because rheumatoid arthritis is immune mediated, sometimes immunosuppressive drugs are needed if disease is severe or if NSAIDs do not provide adequate pain relief.
Whether a pet has osteoarthritis or rheumatoid arthritis, the goal of treatment is to reduce pain and increase joint function. If your pet has been diagnosed with either of these conditions, and you think that you could be doing more to manage her pain, talk to your veterinarian about other options!