Amyotrophic lateral sclerosis: considerations on diagnostic criteria.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder, compromising the motor neuron, characterized by progressive muscle weakness, with reserved prognosis. The diagnosis is based on inclusion and exclusion clinical criteria, since there is no specific confirmation test. The objective of this research is to critically examine the main diagnosis instrument - El Escorial revisited, from the World Federation of Neurology (1998). Of the 540 patients with initial ALS diagnosis, either probable or definite, seen at UNIFESP-EPM, 190 underwent thorough investigation, following regular clinical and therapeutic treatment for over two years. Thirty patients (15.78%) had their diagnosis completely changed. The false-positive diagnoses were related to: early age, clinical presentation of symmetry, weakness greater than atrophy, symptomatic exacerbation. In addition, three patients with myasthenia gravis developed framework for ALS, suggesting the post-synaptic disability as a sign of early disease.