What are the diagnostic criteria and management options for orthostatic hypotension?

Orthostatic Hypotension Diagnostic Criteria

Orthostatic hypotension is diagnosed when systolic blood pressure drops ≥20 mmHg or diastolic blood pressure drops ≥10 mmHg within 3 minutes of standing, or when systolic BP falls to <90 mmHg absolute. 1, 2, 3

Standard Diagnostic Criteria

For patients with baseline supine hypertension, use a more stringent threshold of ≥30 mmHg systolic drop to avoid overdiagnosis. 1, 2

The diagnostic criteria vary by timing and pattern:

• Classical OH: Sustained BP decrease meeting the above criteria within 3 minutes of standing or 60-degree head-up tilt 1, 3
• Initial OH: More severe drop (>40 mmHg systolic and/or >20 mmHg diastolic) occurring within 15 seconds of standing, with rapid spontaneous recovery within 40 seconds 1, 3
• Delayed OH: BP drop meeting standard criteria but occurring beyond 3 minutes of standing, characterized by slow progressive decrease 1, 3

Proper Measurement Technique

The patient must rest supine or sitting for 5 minutes before baseline measurement, then BP should be measured at both 1 minute and 3 minutes after standing. 2, 3

Critical technical requirements include:

• Patient should fast for 3 hours before testing and avoid nicotine, caffeine, theine, or taurine-containing drinks on the day of examination 2
• Testing should occur in a temperature-controlled environment (21-23°C) 2
• Use a validated and calibrated BP device with appropriate cuff size based on arm circumference 2
• Measure BP in both arms at the initial visit; if systolic BP differs by >10 mmHg between arms, use the arm with higher BP for all subsequent measurements 2
• Maintain the arm at heart level during all measurements 2

A common pitfall is using interval BP devices instead of continuous monitoring—these have low concordance (positive agreement only 59.5%) and may miss up to 10% of OH cases. 2, 4 The European guidelines recommend continuous BP measurement devices for accurate diagnosis when available. 2

Distinguishing Neurogenic from Non-Neurogenic OH

The heart rate response differentiates neurogenic from non-neurogenic causes: neurogenic OH shows blunted HR increase (<10 bpm) upon standing, while non-neurogenic OH shows preserved or enhanced HR increase. 1, 5

Neurogenic causes include:

• Primary autonomic failure: Parkinson's disease, multiple system atrophy, pure autonomic failure, dementia with Lewy bodies 1, 5
• Secondary autonomic failure: Diabetes mellitus, amyloidosis, spinal cord injuries, autoimmune autonomic neuropathy 1, 5

Non-neurogenic causes include:

• Medications (most common): diuretics, vasodilators, alpha-blockers, beta-blockers 5
• Volume depletion from excessive diuresis or blood loss 5
• Severe arteriosclerosis causing pseudohypertension 5

Diagnostic Workup

When initial bedside testing is negative but clinical suspicion remains high, extend standing time beyond 3 minutes to detect delayed OH. 2

Additional testing to consider:

• ECG to rule out arrhythmias contributing to symptoms 2
• 24-hour ambulatory BP monitoring to detect patterns of BP variability 2
• Echocardiography only if cardiac cause is suspected with clinical evidence of cardiac disease (diagnostic yield is low without clinical indicators) 2
• Autonomic testing (Valsalva maneuver, deep-breathing testing) when neurogenic OH is suspected, though referral to specialized autonomic centers may be necessary 1

Clinical Pearls

Symptoms depend more on the absolute BP level reached than the magnitude of the fall—a patient dropping from 180/100 to 150/80 mmHg may be asymptomatic despite meeting diagnostic criteria. 2

OH is present in approximately 10% of all hypertensive adults, 30% of patients over 65 years, and up to 50% of older institutionalized adults. 2, 6 It accounts for 20-30% of syncope cases in older adults. 5

Pseudohypertension in elderly patients with calcified arteries may lead to overtreatment of hypertension and iatrogenic OH—consider this when elderly patients develop OH after antihypertensive initiation. 2, 5

Management Approach

Non-Pharmacologic Management (First-Line for All Patients)

All patients should receive non-pharmacologic interventions before considering medications. 1, 7

• Patient education and reassurance (Class I recommendation per European guidelines) 1
• Acute water ingestion (Class I recommendation per U.S. guidelines for neurogenic OH) 1
• Compression garments (support stockings) 8, 7
• Fluid expansion and dietary modifications (increased salt and fluid intake) 8, 7
• Physical counterpressure maneuvers 7
• Avoiding environments that exacerbate symptoms (heat, prolonged standing) 7

Pharmacologic Management

Midodrine is FDA-approved for symptomatic OH and should be used only in patients whose lives are considerably impaired despite standard clinical care, as it can cause marked supine hypertension (>200 mmHg systolic). 9

• Midodrine 10 mg three times daily (last dose not later than 6 PM) increases standing systolic BP by approximately 15-30 mmHg at 1 hour, with effects persisting 2-3 hours 9, 8, 7
• Droxidopa is another first-line medication option 7
• Fludrocortisone improves symptoms but has concerning long-term effects and should be used cautiously 8, 7
• Pyridostigmine has proven beneficial for patients not responding to non-pharmacologic treatment 8

Medication should be continued only for patients who report significant symptomatic improvement, as clinical benefits (improved ability to perform life activities) remain under investigation. 9

Medication Review

Review and discontinue causative medications when possible—this is the most important reversible cause. 5, 7 Common culprits include diuretics, vasodilators, alpha-adrenergic blockers, beta-blockers, and psychotropic drugs. 5, 7