Last week I saw a young Labrador Cross, Daisy, who seemed to have pain if she opened her mouth. The owners were not aware of any trauma that could have occurred. She seemed fine otherwise and was eating normally. When I examined Daisy, I could not look into her mouth because she screamed out in pain anytime we tried to open her jaws. We gave Daisy some pain medications and heavily sedated her. This allowed us to determine that there was no stick or other foreign object stuck in her mouth or throat. We could also see that her teeth looked okay and her jaw could move normally. A series of skull x-rays confirmed that there were no fractures, dislocations or dental abscesses. At this point I was quite sure we were dealing with an autoimmune disease called masseter myositis. Autoimmune refers to the body ™s immune system attacking itself. The masseter muscles are the big ones we use to chew with, and myositis means inflammation of the muscle. Daisy appears to have a self-induced masseter muscle inflammation. A laboratory test will help us to confirm this. Most dogs with this disease do very well with anti-inflammatory drugs, but many need to take the drugs for 6 months and even then some will still have recurrences.
Not every case is exactly what it seems. Daisy is lucky to have owners who brought her in for care early and allowed us to run the tests necessary for a diagnosis with a good prognosis. The doctors and staff at ACC would love to help you with your pets ™ problems.
by Bonnie Markoff, DVM, ABVP