Acute fulminating myasthenia gravis in five dogs.

Acute fulminating myasthenia gravis (MG) was diagnosed in 5 dogs. Acute fulminating generalized MG in dogs is characterized by sudden onset of megaesophagus and frequent regurgitation of large volumes of fluid. Generalized muscle weakness can worsen and lead to recumbency within days. Despite appropriate supportive care, weakness is not alleviated by rest. Respiratory failure caused by aspiration pneumonia and loss of strength in muscles involved with respiration is a common cause of death. In dogs with acute onset of regurgitation, MG should be considered as a differential diagnosis. Clinicians should be aware of the risk of rapid progression to quadriparesis if aspiration pneumonia develops.