Erosive, Immune-Mediated Polyarthritis is a condition in dogs characterized by inflammation of the joints, leading to tissue destruction and erosion within the affected joint due to abnormal immune response. This condition causes erosion of dog's cartilage (articular cartilage).
It is believed that T lymphocytes (a type of WBC) carry out the attach response and the body immune system identifies one or typically multiple body joints as abnormal, resulting in white blood cells entering the joint space . These WBCs then release chemicals, causing inflammation and swelling. In response, joint pain and fever may be noted. Destructive enzymes, which are released from inflammatory cells, damage the articular cartilage, synoviocytes (cells which produce a lubricating fluid, called synovia, for the joints), and chondrocytes (cartilage cells), leading to erosive changes in the joints.
This condition can occur in dogs between eight months to eight years of age. Greyhounds aged 3 to 30 months are most susceptible to erosive polyarthritis of Greyhounds (EPG), a specific type of this disease. The idiopathic erosive polyarthritis (IEP), another form of this disease, can occur in any dog of any age and is of unknown cause.
There are no consistent signs of the disease and many of the signs are fairly general and may be seen with many other conditions. In addition, the signs are often cyclic, coming and going at random intervals. Common symptoms include
Stiffness in walk
Reluctance to walk or stand
Shifting or multiple leg lameness
Decreased range of motion
Cracking sounds from the joints
Joint swelling and pain in one or more joints
Joint instability, subluxation (partial dislocation of the joint), andluxation (complete dislocation of the joint)