Table 1.

Distinauishina features of neurosenic and non-neurosenic orthostatic hypotension

	Non-neurogenic orthostatic hypotension	Neurogenic orthostatic hypotension
Epidemiology	Typically elderly	Typically middle-aged
Onset	Variable	Usually chronic (Acute or subacute with immune-mediated etiology)
Causes	Intravascular volume loss (e.g., dehydration, anemia) Blood pooling (e.g., large varicose veins, skeletal muscle atrophy) Advanced heart failure Adrenal insufficiency Physical deconditioning Antihypertensive medications	Reduced norepinephrine release from sympathetic post-ganglionic nerves when standing up
Prognosis	Resolves when underlying cause is corrected	Chronic disorder
Sympathetic tone	Increased	Low or absent
Increase in heart rate upon standing	Pronounced	Mild or absent
ΔHR/ ΔSBP ratio	> 0.5 bpm / mmHg	< 0.5 bpm / mmHg
Blood pressure overshoot (phase 4) in Valsalva maneuver	Present	Absent
Increase in plasma norepinephrine levels upon standing	Normal or enhanced (at least x2)	Reduced or absent (less than x2)
Other symptoms of autonomic failure	No	Gastrointestinal dysfunction Urinary dysfunction Sudomotor abnormalities Erectile dysfunction (men)
Concomitant neurological deficits	None (or if present, they are unrelated to orthostatic hypotension)	None Parkinsonism Cerebellar signs Cognitive impairment Sensory neuropathy