With this disorder, the cartilage in a dog’s joints is eroded through an inflammatory autoimmune response in which a dog’s body is fighting itself. The disease can occur at any life stage. Greyhounds are at an elevated risk for the disorder, and there is a type of immune-mediated polyarthritis specific to Greyhounds, known as erosive polyarthritis of Greyhounds, or EPG. The symptoms of immune-mediated polyarthritis may resemble other forms of arthritis or, in young dogs, growth-associated bone disorders, and in elderly dogs, age-associated cartilage degeneration. Additionally, there are several non-erosive forms of immune-mediated polyarthritis, the symptoms of which are also similar.

The most obvious symptoms of joint cartilage erosion are those below that point to compromised joint functioning. These physical symptoms may increase and subside periodically, so even if your dog appears to be improving, it is best to seek a veterinary diagnosis if these symptoms are present. However, up to 25% of affected dogs present minute or none of these symptoms and are brought in for diagnosis based only on system symptoms, such as fever.

The most common cause for immune-mediated polyarthritis is idiopathic, meaning that the cause is unknown. Idiopathic joint cartilage erosion occurs most commonly in smaller breed dogs and most commonly affects the joints within a dog’s paw. 

Erosive polyarthritis of Greyhounds affects puppies of the breed between the ages of 3 to 30 months and progresses slowly. 

In order to aid your veterinarian in diagnosis, you must ensure your veterinarian is informed of your dog’s complete medical history and the onset and severity of symptoms. The first step to diagnosis is a thorough physical exam, during which your veterinarian will articulate your dog’s joints in order to monitor any pain, lameness or a decrease in range of motion. This may also include having your dog walk around in order to monitor pain and range of motion as well as how it has affected your dog’s gait. Because there are many other conditions which could cause compromised movement in your dog, this physical examination is the starting point for further diagnostic testing. 

Your veterinarian will need a complete blood count, chemical blood profile, and a urinalysis in order to assess your dog’s overall health and rule out other possible diagnoses. The key to diagnosis joint cartilage erosion is a joint fluid aspirate, or sample of your dog’s joint fluid, which will undergo laboratory analysis for bacterial culture. Further, a biopsy and analysis of synovial tissue will aid in confirming the diagnosis. Additional testing depends upon your dog’s condition and may include an abdominal ultrasound, an antinuclear antibody test, and/or a muscle biopsy.

Dogs with immune-mediated polyarthritis causing joint cartilage erosion will require lifelong therapy in an effort to maintain comfort and mobility. Treatment includes immunosuppressive and anti-inflammatory medications as well as physical therapy, massage and splinting. Splints or bandages may be used in order to relieve pressure on your dog’s joints. Physical therapy treatment will focus on techniques to maintain and improve your dog’s range of motion. Physical therapy may include swimming, or you may be advised to take your dog swimming as an activity that allows your dog to exercise without putting pressure on her joints. For overweight dogs, weight loss is advised in order to ameliorate pressure on joints. 

Surgery to treat joint cartilage erosion is neither common nor recommended. However, in some cases, your veterinarian may advise, or you may elect to attempt a surgical procedure to improve your dog’s condition. Possible surgeries include hip replacement and surgical removal of a portion of the femur. 

Prognosis for erosive immune-mediated polyarthritis is poor, as the condition is progressive. You will need to closely monitor your dog’s recovery and pain levels and return to the veterinarian regularly to assess treatment methods. For most dogs with this condition, exercise routines will need to change in order to alleviate joint stress. The rate of progression does vary, and the amount of years your dog may live comfortably with proper treatment varies as well. In the event that your dog has undergone surgery, you will need to follow all postoperative instructions, which will include restricting activity.