How do you diagnose orthostatic (postural) hypotension?

Diagnosing Orthostatic Hypotension

To diagnose orthostatic hypotension, measure blood pressure after 5 minutes of rest in supine or sitting position, followed by measurements at 1 minute and 3 minutes after standing, with a drop in systolic BP ≥20 mmHg or diastolic BP ≥10 mmHg, or a decrease in systolic BP to <90 mmHg within 3 minutes of standing considered diagnostic. 1, 2, 3

Proper Measurement Technique

• Use a validated and calibrated sphygmomanometer or blood pressure device with appropriate cuff size 1, 3
• Begin with patient resting in supine position (preferred) or sitting position for 5 minutes in a quiet, comfortable environment 2, 3
• Measure baseline blood pressure with the arm at heart level and properly supported 3
• At first visit, measure blood pressure in both arms; if systolic BP differs by >10 mmHg between arms, use the arm with higher BP for subsequent measurements 1, 3
• Have the patient stand (active standing preferred over passive tilt), and measure BP at 1 minute and 3 minutes after standing 1, 2, 3
• Maintain the arm at heart level during all measurements 3
• Record heart rate simultaneously to assess for compensatory increase 1

Diagnostic Criteria

• The test is diagnostic when there is a symptomatic fall in systolic BP ≥20 mmHg or diastolic BP ≥10 mmHg, or a decrease in systolic BP to <90 mmHg within 3 minutes of standing 1, 2
• In patients with supine hypertension, a systolic BP drop ≥30 mmHg should be considered diagnostic 2
• The test should be considered diagnostic even with an asymptomatic fall meeting these criteria 1
• Symptoms may include dizziness, lightheadedness, blurred vision, weakness, fatigue, and headache 4

Advanced Testing Options

• Continuous beat-to-beat non-invasive BP measurement may be helpful in cases of doubt or when more frequent values are required 1
• If standard orthostatic vital signs are nondiagnostic but clinical suspicion remains high, head-up tilt-table testing can aid in confirming the diagnosis 4, 5
• Consider testing for delayed orthostatic hypotension by extending standing time beyond 3 minutes if symptoms suggest OH but initial testing is negative 2

Common Pitfalls and Considerations

• Sitting-to-standing measurements alone have poor sensitivity (15.5%) compared to proper supine-to-standing or tilt-table testing 6
• Reproducibility when testing for orthostatic hypotension is poor; consider repeat testing if clinical suspicion is high despite negative initial results 7
• When assessing patients with atrial fibrillation, use a manual auscultatory method as most automated oscillometric monitors have not been validated for BP measurement in AF 1
• Assess for orthostatic hypotension at initial diagnosis of elevated BP/hypertension and whenever suggestive symptoms arise 1
• For diabetic patients, be particularly vigilant as they have higher prevalence of orthostatic hypotension due to autonomic neuropathy 1, 5

By following this structured approach to testing for orthostatic hypotension, you can accurately diagnose this condition and identify patients who may benefit from appropriate management strategies.