Man in the Barrel Syndrome, a rare symmetrical proximal amyotrophic diplegia case report

Resumen

Introduction: Brachial amyotrophic diplegia (BAD), also known as flail arm syndrome or man-in-the-barrel syndrome, is a rare regional variant within the motor neuron disease spectrum, characterized by progressive lower motor neuron weakness and atrophy predominantly restricted to the upper limbs.

Case report: We report the case of a 62-year-old man with progressive bilateral upper-limb weakness and amyotrophy, with distal predominance, evolving for nearly two years. Neurological examination showed preserved lower-limb strength, absence of sensory abnormalities, and no clinical signs of upper motor neuron, bulbar, or respiratory involvement. Electroneuromyography demonstrated a chronic, purely motor, preganglionic neurogenic pattern affecting the upper limbs. Extensive laboratory, neuroimaging, respiratory, swallowing, and genetic investigations did not reveal alternative etiologies.

Discussion: The clinical and electrophysiological findings, together with the absence of progression to other motor territories, support the diagnosis of BAD. The distal predominance observed in this case differs from the classically described proximal pattern, suggesting phenotypic variability within this rare entity.

Conclusion: This case contributes to the recognition of BAD in the Brazilian context and highlights the importance of systematic investigation to distinguish it from classical amyotrophic lateral sclerosis and other motor neuron disease mimics.