What is Neurogenic Orthostatic Hypotension
Neurogenic orthostatic hypotension is a subtype of orthostatic hypotension caused by autonomic nervous system dysfunction—not environmental triggers like dehydration or medications—resulting in a sustained blood pressure drop (≥20 mmHg systolic or ≥10 mmHg diastolic) within 3 minutes of standing, with a characteristically blunted heart rate response (<10 bpm increase). 1
Defining Characteristics
Hemodynamic Criteria
- Blood pressure drop: Sustained decrease in systolic BP ≥20 mmHg, diastolic BP ≥10 mmHg, or systolic BP falling to <90 mmHg within 3 minutes of standing or 60-degree head-up tilt 1, 2
- In patients with supine hypertension: A systolic BP drop ≥30 mmHg should be considered diagnostic 2
- Hallmark autonomic feature: Heart rate increase is typically blunted (<10 beats per minute) due to impaired autonomic heart rate control, distinguishing it from non-neurogenic causes 2, 3
Pathophysiology
- Results from lesions involving central or peripheral autonomic nerves, causing impaired vasoconstriction and inadequate compensatory increases in total peripheral resistance and heart rate 1
- Blood pools in lower extremities upon standing due to failed autonomic compensation 2
Underlying Neurological Disorders
Primary Autonomic Failure
- Multiple system atrophy 1, 4
- Parkinson's disease 1, 4
- Pure autonomic failure 1, 4
- Dementia with Lewy bodies 1
Secondary Autonomic Failure
- Diabetes mellitus (autonomic neuropathy) 1
- Amyloidosis 1
- Spinal cord injuries 1
- Autoimmune autonomic neuropathy 1
- Paraneoplastic autonomic neuropathy 1
- Kidney failure 1
Clinical Presentation
Symptoms
- Most frequent: Dizziness or lightheadedness, fatigue when standing, difficulty walking 5
- Additional symptoms: Presyncope, syncope, visual and hearing disturbances, generalized weakness, blurred vision 2, 4
- Atypical presentations: Neck and shoulder pain ("coat hanger" distribution), low back pain, or precordial pain, particularly in autonomic failure 2
- Timing pattern: Symptoms develop upon standing, are relieved by sitting or lying, and may be worse in the morning, with heat exposure, after meals, or with exertion 2
Critical Clinical Pitfall
- Hypotensive unawareness: Patients not able to recognize neurogenic orthostatic hypotension symptoms are at higher risk for falls 6
- Despite meeting diagnostic criteria, formal diagnosis is reported by only 36% of patients, suggesting substantial underdiagnosis 5
Impact on Morbidity and Quality of Life
Falls and Functional Impairment
- Falls (≥1) in the previous year due to neurogenic orthostatic hypotension symptoms were reported by 57% of patients and 80% of caregivers 5
- Negative impact on quality of life reported by 59% of patients and 75% of caregivers 5
- Most respondents (≥87%) reported adverse effects on everyday activities, most frequently physical activity/exercise, housework, and traveling 5
Mortality Risk
- Classic orthostatic hypotension is associated with increased mortality and cardiovascular disease prevalence 2
- Impaired recovery of blood pressure after initial fall represents a negative prognostic factor in the elderly 2
Distinguishing from Other Forms of Orthostatic Hypotension
Non-Neurogenic Orthostatic Hypotension
- Caused by environmental triggers: dehydration, medications (diuretics, vasodilators, alpha-blockers), or severe volume depletion 1, 3
- Key difference: Normal or exaggerated heart rate response (>15-20 bpm increase) upon standing 2
Other Orthostatic Hypotension Subtypes
- Initial orthostatic hypotension: BP decrease >40 mmHg systolic and/or >20 mmHg diastolic within 15 seconds of standing with rapid spontaneous recovery 1, 2
- Delayed orthostatic hypotension: BP drop occurring beyond 3 minutes of standing with slow, progressive decrease 1, 2