Pearls & Oy-sters: The importance of atypical features and tracking progression in patients misdiagnosed with ALS

The clinical diagnosis of amyotrophic lateral sclerosis (ALS) is based on the presence of upper and lower motor neuron abnormalities spreading between body segments, along with the exclusion of rare disease mimics. No definitive diagnostic testing exists. Accurate, timely diagnosis of ALS is essential in order to provide appropriate patient counseling. While the revised El Escorial criteria provide standards for research purposes,1 trainees should be aware that many patients never meet criteria for definite ALS. ALS is a clinically heterogeneous disorder and presentations vary in regards to the distribution of weakness, rate of progression, and survival.2,3 Approximately 10% of patients with ALS will live more than 10 years.4 Patients carrying certain mutations in TARDBP and MART3 may have a longer survival.5,6 Despite this heterogeneity, a small number of patients carry an inaccurate diagnosis.