Arthritis is a complex condition involving inflammation of joints. There are many causes of arthritis in pets. In most cases, the degree of arthritis is related to the age of the animal. The most common type of arthritis is osteoarthritis (OA) which is also known as degenerative joint disease (DJD). This can be primary , the cause of which is unknown and secondary , following conditions involving joint instability leading to damage of the subchondral bone that line the joints. Some common causes of DJD include hip dysplasia, cranial cruciate ligament rupture, and so forth. Other causes include joint infection, often as the result of bites or injuries or it may follow joint trauma and damage.
Rheumatoid arthritis is an immune mediated, erosive, inflammatory condition. Cartilage and bone are eroded within affected joints and the condition can progress to complete joint fixation, (ankylosis). It may affect single joints or multiple joints may be involved (polyarthritis). In certain dog breeds Rheumatoid Arthritis (RA) factors can be detected with blood tests. Other types of immune mediated arthritis can be non-erosive, such as arthritis that is associated with Systemic Lupus Erythematosis (SLE). SLE is often accompanied by other clinical signs in addition to the arthritis. Infective or septic arthritis can be caused by a variety of microorganisms, such as bacteria, viruses and fungi. Septic arthritis normally only affects a single joint and the condition results in swelling, fever, heat and pain in the joint. Before long your pet is likely to stop eating and become depressed.