Myasthenia Gravis

Myasthenia Gravis (MG) is an immune system disease in which antibodies are produced against receptors in the muscle junction. It is characterized by episodic weakness associated with exercise.

Signs of Myasthenia Gravis

A dog's stride may be shortened, followed by collapse in the hind legs, or all four limbs. Paresis (a disturbance in the mechanism for initiating voluntary motor function that causes weakness and paralysis) may involve facial nerves as well as spinal nerves. Inability to blink both eyes is most commonly observed along with generalized muscle weakness.

Additionally, there may be a change in bark, respiratory difficulty, and vomiting. The vomiting is due to a megaesophagus (abnormal/enlarged esophagus).

MG can be either congenital or acquired. Springer spaniels, Jack Russell terriers, and Fox terriers have been reported to have congenital MG.

Diagnosis of Myasthenia Gravis

Diagnosis is made through the use of a test dose of a medicine called edrophonium chloride given intravenously. An immediate short-lived (3-8 minute) response is observed.

Treatment of Myasthenia Gravis

Long-term treatment requires a longer-acting medicine and corticosteroids.