[Myasthenic syndrome in a patient with end-stage amyotrophic lateral sclerosis].

Amyotrophic lateral sclerosis (ALS) and myasthenia gravis are diseases with similar clinical features but different prognosis and approach to treatment. It is possible as an extremely rare combination of these diseases, as well as myasthenia gravis with signs of ALS (MuSK-positive), as well as ALS, accompanied by myasthenic syndrome. Latter option is the most common. Myasthenic syndrome accompanying the ALS characterized by pathological muscle fatigue signs, symptoms variability during the day, partial sensitivity to neostigmine, M-wave decrements detection during electromyographyc study. We present a case of a patient with terminal ALS and myasthenic syndrome. The main pathogenesis theories of this condition and the differential diagnosis of ALS and myasthenia gravis are discussed.