Pure Autonomic Failure Versus Prodromal Dysautonomia in Parkinson's Disease: Insights from the Bedside

Autonomic failure may include orthostatic hypotension, supine hypertension, bowel and bladder disturbances, impaired thermal regulation, and sexual dysfunction, all of which can be features of Parkinson's disease (PD) and other a-synucleinopathies. All patients with pure autonomic failure, most patients with multiple system atrophy, and 18% of patients with PD will develop symptomatic orthostatic hypotension. However, the extent of central and peripheral norepinephrine deficiency, parasympathetic nuclei degeneration, and arterial baroreflex failure may be differentially impaired in these disorders. Consequently, clinical features and prognostic implications of autonomic dysfunction in a-synucleinopathies may be more complex than previously envisioned. The case described in this report highlights the clinical similarities between PD and pure autonomic failure, raising the question of whether pure autonomic failure represents a restricted Lewy body synucleinopathy or an early manifestation of PD.