Swollen joints in dogs occur with many joint problems and can seriously affect your dog’s mobility. It refers to an increase of fluid within the joint which may be undetectable or large enough to cause distension of the joint. It is important to consult with your veterinarian at the first signs of swollen joints. Your veterinarian will carry out a physical examination to determine if swelling is due to any trauma or injury to the joint, leg or toes such as an accident or fall. With trauma, inflammation may be due to inflammation or bleeding of the joint. If bacteria or infection has entered the skin through an open wound it can also create swelling, inflammation and pain. For example, ruptured cruciate ligament can cause degeneration of the knee joint as a result of a tear to the cruciate ligament. It can be caused by an athletic injury. It is also more susceptible in overweight or large breed dogs. Immune mediated polyarthritis is another condition which causes inflammation and swelling in more than one joint due to an abnormal immune response where the body fights itself, damaging the joint cartilage.
Swollen joints in dogs can also be caused by forms of dysplasia such as Hip dysplasia, which is considered a genetic disorder where the ligaments within the muscles have become loose and the hip and thigh bones are no longer a close fit. This leads to abnormal structure of the muscles and connective tissues and affects the range of motion in the hip joint. The surfaces of the bones within the joint become separated (sublaxation). In the most advanced stages, the cartilage is worn away leading to exposed bones causing severe pain and inflammation. Arthritis is a degenerative joint disease which may also lead to swollen joints in dogs. In healthy joints, cartilage cushions and protects the bones at the point where they meet, enabling flexible and easy movement. In degenerative joint disease, cartilage is worn away and bones may become exposed leading to exposed nerves, inflammation and pain.
Other causes of swollen joints in dogs include infectious joints diseases such as Lyme disease, Rocky mountain fever, septic bacterial infections, tumors or bone cancers, and clotting abnormalities. Some forms of swelling are breed specific. Symptoms of swollen joints are usually addressed by treating the underlying cause.