Clinical Reasoning: A 57-Year-Old Man With Chronic Gait Unsteadiness and Diminished Lower Extremity Sensation.

A 57-year-old man presented with a 5-year history of progressive gait unsteadiness, diminished lower extremity sensation, and a chronic cough. His symptoms began as episodic balance issues and visual disturbances but progressively worsened, leading to frequent tripping. Physical examination revealed sensory deficits in the lower extremities and cerebellar signs, including nystagmus, dysmetria, and a broad-based gait. Readers will walk through a stepwise approach to the case, developing a comprehensive differential diagnosis and questioning likely etiologies to arrive at a final diagnosis. This case illustrates the challenges of diagnosing complex ataxia and highlights the importance of considering multisystem disorders.