Not All That Looks Like ALS Is ALS: Spectrum of Amyotrophic Lateral Sclerosis Mimics at a Tertiary Neuromuscular Center
Authors
Jharna Mahajan, Dr Satish Khadilkar, Dr Shamisha Khade, Dr Ankur BhootFiles
Key Information
Journal
Published in Vol. 68 No. 1 (2026) of Bombay Hospital Journal.
Bombay Hospital Journal (BHJ) is a peer-reviewed quarterly published Print and Online journal. It is an official Journal of Bombay Hospital institute of medical sciences. The aim of BHJ is to improve medical care by publishing sound scientific articles (both research and practice papers) and focusing on topics that are of great importance to its readership.
Editor-in-Chief- Dr Satish Vasant Khadilkar
About the JournalAbstract
Abstract
Background:
Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron disorder diagnosed clinically in the absence of a definitive biomarker. Several neuromuscular and structural disorders can closely mimic ALS, leading to diagnostic errors with significant prognostic and therapeutic implications.
Objective:
To analyze the spectrum, clinical characteristics, and key predictors of ALS mimic disorders among patients referred with suspected ALS at a tertiary neuromuscular center.
Methods:
This retrospective observational study reviewed approximately 500 patients referred with a provisional diagnosis of ALS between January 2021 and December 2025. Clinical data, electrophysiology, neuroimaging, and relevant laboratory investigations were analyzed. Fifty-one patients with confirmed ALS mimic diagnoses and complete clinical data were included. Comparative analyses with published ALS epidemiologic parameters were performed using Student’s t-test and chi-square/Fisher’s exact tests. Multivariate logistic regression was used to identify predictors of ALS mimic diagnosis.
Results:
The most frequent ALS mimics were Hirayama disease (29.4%), post-polio syndrome (23.5%), and adult-onset spinal muscular atrophy (23.5%). Patients with ALS mimics were significantly younger at symptom onset than reported ALS cohorts (19.1 ± 3.6 vs 58.7 ± 11.3 years; p <0.001). Bulbar onset was absent in the mimic cohort (p <0.001). Conduction block on electrophysiology and structural spinal abnormalities on MRI were significantly associated with mimic diagnoses. Multivariate analysis identified age <40 years, absence of bulbar onset, conduction block, and MRI structural abnormalities as independent predictors of ALS mimic disorders.
Conclusion:
ALS mimics represent a substantial proportion of patients referred with suspected motor neuron disease. Recognition of clinical red flags, careful electrophysiological interpretation, and routine spinal imaging are essential to avoid misdiagnosis and identify treatable conditions.
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