Coexistence of Amyotrophic Lateral Sclerosis and Myasthenia Gravis.

The mechanisms by which amyotrophic lateral sclerosis (ALS) causes motor neuron degeneration remain unknown. We present the case of a 77-year-old Japanese female with clinically probable ALS, who developed ALS symptoms 41 years after onset of myasthenia gravis (MG). We concluded that neither the relapse of MG nor the adverse effects of anti-cholinesterase medication aggravated her symptoms. Although MG and ALS are extremely rare, we reviewed several case reports describing their coexistence. We suggest that clinicians should consider the possibility of ALS occurring with MG. Further investigations will improve our understanding of the pathogenic relationship between ALS and MG.