Autonomic dysfunction in Parkinson disease.

In Parkinson disease (PD), symptoms and signs of autonomic failure occur commonly, especially in cardiovascular, gastrointestinal, and genitourinary domains. Most patients with PD have neuroimaging evidence of cardiac sympathetic denervation. In PD, orthostatic hypertension (OH) can be an early finding and is associated with extracardiac noradrenergic denervation and reduced baroreflex-cardiovagal and sympathoneural responses. Recognition of autonomic impairment is important because symptomatic treatment is frequently effective.