Your German Shepherd Cannot Chew His Food Or Drink? It Could Be Masticatory Muscle Myositis

If your once-healthy German Shepherd all of a sudden cannot chew its food or drink, it could have a disease called masticatory muscle myositis (MMM). This is an inflammatory disease that mainly affects the chewing muscles in the jaw. In some cases, this disease can also affect the eye muscles, which causes the eye(s) to droop, and can result in blindness if not treated properly. This disease commonly affects large breed dogs, and German Shepherds are predisposed to it.  

Symptoms of Masticatory Muscle Myositis

The symptoms of MMM include:

  • Cannot open jaw
  • Pain in the jaws
  • Atrophy or swelling of the jaw muscles
  • Difficulty in drinking and eating
  • Protruding or sunken eyes
  • Reluctant to play with toys
  • Severe drooling
  • Foaming at the mouth

The sooner you notice these symptoms, you should seek veterinarian care as soon as possible. The quicker this disease is diagnosed and treated, the best outcome your dog can have.

Cause of Masticatory Muscle Myositis

There are four muscles in the jaw area of your dog: temporalis, pterygoid, rostral digastricus, and masseter. There are 2M fibers in all four of these muscles. With some dogs, their immune system thinks the 2M fibers are bacteria. As a result, it starts attacking the 2M fibers, and then inflammation occurs leading to MMM.  Doctors have no idea why a dog's immune system attacks these muscles when 2M fibers are found.

If one or more of the dog's parents had MMM, your dog has a higher chance of developing it. In this case, there may be triggers that can cause your dog to develop it. These triggers may include some vaccinations, medications, environmental toxins, hormones, and stressful situations.

Diagnosing Masticatory Muscle Myositis

A veterinarian can generally diagnose MMM very quickly by the symptoms your dog is exhibiting. They still have to confirm this diagnosis, however. To do this, the doctor may do a muscle biopsy, imaging electromyography, CT, and MRI. They may do a blood test looking for the 2M antibody. Your veterinarian can explain to you in detail how these things can help them diagnose MMM.


Your veteranian will likely start your dog on an IV of corticosteroids as well as fluids in case your dog is slightly dehydrated because they cannot drink. The corticosteroids help calm the inflamed muscles so your dog can regain jaw movement. The doctor will likely prescribe steroid medication for your dog to take for a certain amount of time at home until its jaw function is back to normal.

To help further, purchase some tennis balls for your dog to play with at home, as well as a rawhide to chew on to help strengthen the jaw muscles.

If MMM is found and treated early by your veterinarian, your dog should have a good prognosis. 

For a local vet, contact a company such as Stroudsburg Animal Hospital.