Masticatory Myositis in Dogs: Understanding the Symptoms, Causes, and Diagnosis
As pet owners, we are responsible for the health and wellbeing of our furry friends. One autoimmune disease that affects dogs is Masticatory Myositis (MMM).
In this article, we will provide a comprehensive overview of MMM to help pet owners understand the symptoms, causes, as well as the diagnosis of this condition.
Definition and Description of MMM
MMM is an autoimmune disease that causes inflammation in the muscles responsible for chewing, mainly the temporalis and masseter muscles. The disease occurs when the immune system attacks these muscles, leading to their inflammation, which may impair their function.
As a result, dogs may experience difficulties with eating, opening their mouths, pain, and muscle shrinkage.
Symptoms of MMM
The most common symptoms of MMM in dogs include lethargy, fever, unwillingness to eat, drooling, muscle shrinkage, anorexia, and weight loss. As the disease progresses, dogs may experience difficulties opening their jaws and require soft, liquid diets or feeding tubes.
Causes of MMM
The exact cause of MMM is unknown, but it is believed to be an autoimmune disease, which means the immune system attacks the body’s own tissues and organs. Additionally, parasitic or viral infections, vaccines, reactions to medications, environmental toxins or allergens, stress, and cancer are thought to be contributing factors.
Diagnosis of MMM in Dogs
Diagnosis of MMM in dogs is typically based on a veterinarian’s suspicion and a combination of tests. The following tests may be used to diagnose MMM in dogs:
Bloodwork
Bloodwork helps to determine if there is an anemia (low red blood cells) or if there is an increase in white blood cells or globulins, which may suggest inflammation. Elevated levels of creatine kinase (CK) and aspartate aminotransferase (AST) are also common indicators of muscle damage.
Oral examination under anesthesia
During an oral examination, the veterinarian will check if your dog can clench their jaw and if there is a pain response when the jaw is moved. The inability to open the jaw or a reduction in the jaw’s range of motion is an indication of MMM.
Blood test and muscle biopsy
A blood test may indicate the presence of circulating autoantibodies, which are a hallmark of MMM. A muscle biopsy may also reveal inflammation and fibrous tissue, providing further evidence of MMM.
Conclusion
Masticatory Myositis is an autoimmune disease that affects dogs, causing inflammation in the muscles responsible for chewing. The symptoms of MMM include lethargy, fever, unwillingness to eat, drooling, muscle shrinkage, anorexia, and weight loss.
The exact cause of MMM is unknown, but contributing factors include parasitic or viral infections, vaccines, reactions to medications, environmental toxins or allergens, stress, and cancer. Diagnosis of MMM in dogs involves bloodwork, an oral examination under anesthesia, and a blood test or muscle biopsy.
If you suspect that your dog has MMM, it’s important to work with your veterinarian to diagnose and treat the condition promptly. Masticatory Myositis in Dogs: Treatment, Recovery, and Prognosis
Masticatory Myositis (MMM) is an autoimmune disease that affects a dog’s chewing muscles, causing inflammation and pain.
The condition, if left untreated, can severely affect a dog’s quality of life, leading to weight loss, inability to eat, and muscle atrophy. In this article, we’ll discuss the treatment options for MMM, recovery and prognosis, and the steps you can take to manage and prevent relapse.
Spontaneous Improvement vs. Therapy
Some dogs with MMM may experience spontaneous regression of autoantibodies, leading to an improvement in their condition without any specific therapy required.
However, in most cases, treatment with immunosuppressive drugs is necessary to manage the disease.
Corticosteroids as the Drug of Choice
Corticosteroids, such as prednisone and prednisolone, are the traditional and most effective drugs for treating MMM in dogs. They act by suppressing the immune system and reducing inflammation.
The veterinarian will generally prescribe high doses initially, which can be tapered slowly as improvement is noted. The side effects of corticosteroids include increased thirst, appetite, and urination, as well as gastrointestinal upset or lethargy.
If these side effects become apparent, the veterinarian may add medications to alleviate them, or switch to alternative drugs to prevent adverse effects.
Other Immunosuppressive Drugs
In addition to corticosteroids, other immunosuppressive drugs may be prescribed if the disease is severe, unresponsive to standard therapy, or recurring. These drugs are used alone or in combination with other medications, and they act by suppressing the immune system.
Some examples include:
– Azathioprine: This drug is commonly used in dogs with MMM and may be given with a corticosteroid. It takes several weeks to reach full effect.
– Cyclosporine: This medication is often used for MMM in dogs that have side effects from corticosteroids or don’t respond to them. – Cytarabine: This drug is used in more severe cases of MMM but may have side effects, including vomiting, lethargy, or bone marrow suppression.
– Cyclophosphamide: This medication is considered in refractory MMM cases, but it has some severe side effects such as bladder toxicity and bone marrow suppression.
– Mycophenolate: This medication is used to treat immune-mediated diseases and is being used in dogs with MMM.
Pain Management and Feeding Recommendations
Pain management is essential in dogs with MMM as they may experience difficulty eating or opening their mouths, which can contribute to weight loss and further clinical decline. The veterinarian may prescribe pain medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs), opioids, or in severe cases, nerve block injections.
Additionally, feeding recommendations may be necessary to accommodate the dog’s inability to chew. Softening of dry food with warm water, canned food, or calorie-dense liquid formulations may be recommended during the acute phase of the disease.
Management and Prevention of Relapse
During treatment, the veterinarian will work closely with the dog owner to ensure the medication’s appropriate doses and lengths of time prescribed – discontinued treatment prematurely can lead to relapse. The veterinarian will monitor the dog’s condition by performing routine bloodwork, checking for signs of recurrence, or relapse.
Preventative measures may include regular monitoring and close follow-ups, avoiding environmental triggers, or reducing stressors.
Recovery and Prognosis of MMM in Dogs
Most dogs with MMM respond well to corticosteroid therapy within a few weeks of treatment, showing significant clinical improvement. Tapering of medications is usually gradual and dependent on bloodwork and clinical examination.
In some cases, fibrous changes may occur within the muscle, and this may require more aggressive treatment. The prognosis for MMM in dogs is generally good if the disease is appropriately managed.
While relapse can occur, most dogs respond well to treatment and can resume a high quality of life. Close follow-ups with a veterinarian is essential in managing relapse or flare-ups.
Conclusion
Masticatory Myositis is an autoimmune disease that affects a dog’s chewing muscles. Treatment with corticosteroids and other immunosuppressive drugs can manage the disease effectively.
Dogs with MMM may require pain management and feeding recommendations during treatment, with close monitoring and preventative measures to manage relapse. With appropriate management, most dogs with MMM can have a favorable prognosis, recover well, and resume a high quality of life.
In summation, Masticatory Myositis is an autoimmune disease that affects a dog’s quality of life by inflaming their chewing muscles. Though the exact cause of MMM is unknown, treatment options include corticosteroids and other immunosuppressive drugs, plus pain management and feeding recommendations.
With these treatments, MMM can typically be managed, and most dogs can have a favorable prognosis, recover well, and resume a high quality of life. Regular follow-up appointments with a veterinarian are essential for managing relapse or flare-ups.
As pet owners, it is our responsibility to understand this disease’s symptoms and causes to identify MMM early and initiate prompt treatment. In doing so, we can help our furry friends win the battle against MMM.