Myasthenia Gravis- a Zebra cause of Hind End Weakness

Dr. Cara McNamee

In rehab, we see a lot of dogs that present for hind end weakness. There can be many causes, ranging from arthritis, ligament strains or tears, to disc disease and spinal strokes. One unusual cause of hind end weakness can be caused by an autoimmune disease, myasthenia gravis.  

View fullsize

A custom measured and fit dog wheelchair can increase mobility in dogs with Myasthenia Gravis or other neurological or musculoskeletal conditions where hind end weakness or paralysis occurs.

Learn more about carts and how we can help here!

Myasthenia gravis (MG) is a neuromuscular disorder that can affect dogs of all ages, breeds, and genders, but tends to happen more in older dogs. It is an autoimmune disease that occurs when the immune system attacks the acetylcholine receptors (AChRs) at the neuromuscular junction, resulting in muscle weakness and fatigue. The condition can affect any voluntary muscle, including those used for chewing, swallowing, and breathing. While MG is relatively rare in dogs, it is more commonly diagnosed in certain breeds, such as German Shepherds, Golden Retrievers, and Labrador Retrievers. 

Dr. Wininger of @AnimalNeuroDoc on Instagram posted this video showing how the symptoms of Myasthenia gravis (MG) can show up.

Symptoms of myasthenia gravis in dogs can be subtle or sudden and can vary in severity. Some of the most common signs of MG in dogs include weakness and fatigue, difficulty swallowing, drooping eyelids, and an inability to hold the head up or stand. Dogs with severe MG may also experience respiratory distress, which can be life-threatening if not treated promptly.

View fullsize

Though MG is rare in dogs, German Shepherds are one of the breeds that it shows up in more commonly.

A diagnosis of MG in dogs typically involves a thorough physical examination, blood tests to measure AChR antibodies, and nerve conduction studies to evaluate muscle function. Treatment options for MG in dogs include immunosuppressive drugs, such as prednisone and azathioprine, as well as acetylcholinesterase inhibitors to help improve muscle function. In some cases, dogs with severe MG may require hospitalization for supportive care, such as oxygen therapy and intravenous fluids. A common complication of myasthenia gravis can be aspiration pneumonia, so prompt diagnosis and treatment is important.

While we are unable to definitively diagnose MG here at RVM, we are able to communicate our findings to primary care veterinarians and specialists in order to get your dog the best possible care right away.