Treatment for Myositis in dogs is usually aimed at trying to counteract the ‘over-excitation’ of the immune system by giving drugs to suppress the immune system (immunosuppressives). The main treatment is usually high doses of steroids (prednisolone). Other immunosuppressive drugs (such as azathioprine, cytarabine, mycophenolate, cyclosporin, and cyclophosphamide) can also be used in combination with steroids. The short-term aim of the treatment is to return the animal to normal using high doses of medication. When the disease is controlled the quantity of drugs is slowly reduced (hopefully without the animal relapsing). The long-term aim is to take the animal off any drugs, but usually this is not possible and a continued low dose of medication is needed to keep symptoms at bay.
The signs caused by Myositis in dogs can vary considerably depending on the muscles affected. Masticatory Muscle Myositis initially causes swelling of the muscles on the top of the head followed, a week or two later, by progressive muscle wasting (loss of muscles). The dog usually has difficulty moving its jaw, which causes pain and problems when picking up food or drinking.
An animal with a generalised Myositis (Polymyositis) has a stiff ‘stilted’ gait, muscle pain, weakness and cannot exercise normally. In the early stages of disease generalised muscle swelling occurs and later the muscles are wasted. Other signs associated with Polymyositis include regurgitation of food and water, difficulty swallowing and sometimes breathing problems. Some breeds of dog (Rough coated collies, Shetland sheepdogs, Australian cattle dogs) have a condition called Dermatomyositis in which skin lesions develop associated with muscle atrophy, pain or abnormal gait.
Eventually, Masticatory Muscle Myositis causes the muscles to become fixed so that the dog cannot open its mouth. The eyes may also appear sunken as muscles behind the eye shrink. Myositis in the muscles around the eye initially cause protrusion of the eyeball. There may be swelling around the eye eventually associated with deviation of the eyeball, and impaired vision.
Myositis in dogs can be confirmed by taking a sample of muscle tissue for examination. This will show the inflammatory cells within the muscle. Masticatory Muscle Myositis can be diagnosed by a simple blood test which measures the level of antibody directed against the masticatory muscle (2M antibody titre test). Other tests may be necessary to eliminate a potential infection (blood tests) or to rule out the presence of a cancer in the body (neurological – chest and abdominal X-rays and ultrasound).
Symptoms of Atrophy of Muscles in Dogs
Atrophy of muscles in dogs can come on slowly due to aging or it can quickly occur, causing a younger dog to look sunken or thinner. Any time you notice that there is a difference in your dog’s muscles, either they look swollen or thinner, you need to have your veterinarian look your dog over. Your veterinarian will need to determine if the changes are normal or if there is an underlying condition that needs to be addressed. Signs of atrophy of muscles in dogs include:
The causes of muscle atrophy in dogs
Let’s have a closer look at these two causes…
Help your aging pet fight muscle atrophy
What is muscle atrophy in dogs? You might already be familiar with the term ‘Muscle Atrophy’, or it could be the first time you’ve ever heard of it. Either way, it’s something all dog owners should be aware of and understand.