The First Step: The first step in caring for your pet with arthritis is making sure the disease is diagnosed correctly. The symptoms of arthritis can be hard to distinguish—animals can't complain about their aching joints, so all that pet "parents" see is a response to pain. Animals with arthritis might avoid the activities they used to enjoy, stop jumping onto the furniture, or they might nip or seem upset when touched. Some animals may become depressed or change their eating habits; others may simply seem grumpier than usual. These symptoms can also indicate very serious problems, however, such as hypokalemia (low blood potassium) in cats, cognitive dysfunction, or certain cancers. To be sure your pet is healthy, it's important that you take you pet to the veterinarian if you suspect she has arthritis. Your veterinarian can also help your pet by finding out what kind of arthritis she has, using a combination of a medical history, physical exams, X rays, blood tests, and occasionally tests on the fluid inside the joint or MRI imaging. Though it is relatively uncommon, sometimes arthritis can be caused by a bacterial infection inside a joint or an autoimmune disorder. These are treated with different medications than the more common osteoarthritis. Arthritis caused by hip or elbow dysplasia can sometimes be treated surgically. Your veterinarian needs to rule out these options before you move on to treating your pet's arthritis. Osteoarthritis, also called degenerative joint disease, is the most common type of arthritis in animals as well as in humans. Most elderly dogs and cats suffer from osteoarthritis to some degree. Over time, the cartilage that cushions joints wears down and bones start rubbing against each other. As the condition progresses, the friction can wear down and damage the bones themselves. This kind of arthritis can occur anywhere there is a joint, though it is most common and causes the most pain in the weight-bearing joints like the shoulders, hips, elbows, knees, and ankles. It can be easily seen in large-breed dogs, because their frames have to carry the most weight, but cats and smaller dogs are affected as well. Though there is no cure for osteoarthritis, it can be managed well through medical treatment, environmental adaptation, and diet and exercise.