Clinical Reasoning: A 72-Year-Old Man With Progressive Pan-Dysautonomia.

Dysautonomia is a common clinical feature among many central and peripheral neurologic disorders. Evaluation of patients with dysautonomia can be challenging in the absence of a previously established neurologic diagnosis. In this case, we discuss a 72-year-old man who presented with 9 months of progressive dysautonomia including orthostatic hypotension, urinary retention, erectile dysfunction, and constipation. A combination of autonomic testing and serologic testing confirmed the final diagnosis. This case highlights the differential diagnosis of autonomic failure, emphasizing the role of specific clinical, laboratory, and imaging cues in guiding clinical reasoning.