How is orthostatic hypotension diagnosed?

Diagnosis of Orthostatic Hypotension

Orthostatic hypotension is diagnosed by measuring a reduction in systolic blood pressure ≥20 mmHg or diastolic blood pressure ≥10 mmHg within 3 minutes of standing from a supine position. 1

Diagnostic Procedure

Proper Measurement Technique

1. Have the patient rest in a supine position for 5 minutes
2. Measure baseline blood pressure after this rest period
3. Ask the patient to stand
4. Measure blood pressure at 1 minute and 3 minutes after standing 1
5. Use a validated and calibrated blood pressure measurement device

Diagnostic Patterns

• Classical orthostatic hypotension: Characterized by an immediate BP decrease after standing with a distinctive "concave" curve pattern 2, 1
• Delayed orthostatic hypotension: BP decreases more gradually with variable patterns of decrease 1
• Neurogenic orthostatic hypotension: Features a blunted heart rate response (usually <10 bpm) with the standard BP drop criteria 1

Diagnostic Considerations

Testing Accuracy

• Head-up tilt testing with continuous beat-to-beat plethysmography is considered the reference standard for diagnosis 3
• Simple sit-to-stand testing has very low diagnostic accuracy (sensitivity of only 15.5%) 3
• At least 2 minutes in the upright position is required for accurate diagnosis 4

Pattern Recognition

The European Society of Cardiology highlights specific patterns that help differentiate orthostatic hypotension from other conditions:

• In classical OH, BP starts decreasing immediately after standing with a "concave" curve shape 2
• In neurogenic OH, there is often a lack of significant HR increase, indicating impaired HR control 2
• Supine hypertension is common in patients with neurogenic OH 2

Common Pitfalls to Avoid

1. Inadequate rest period: Failing to allow 5 minutes of rest before baseline measurement can lead to inaccurate results
2. Improper timing: Not measuring BP at both 1 and 3 minutes after standing
3. Using sit-stand measurements: This method has poor sensitivity compared to supine-to-stand measurements 3
4. Ignoring reproducibility issues: OH testing has poor reproducibility, so repeated measurements may be necessary 4
5. Relying solely on BP numbers: Consider symptoms alongside BP measurements for clinical relevance

Additional Testing

If standard orthostatic vital signs are nondiagnostic but clinical suspicion remains high:

• Consider head-up tilt-table testing 1, 5
• Ambulatory BP monitoring may help identify abnormal diurnal patterns 1

Symptoms to Evaluate

• Common: dizziness, lightheadedness, blurred vision, weakness, fatigue, nausea, palpitations, headache 5
• Less common: syncope, dyspnea, chest pain, neck and shoulder pain (coat hanger syndrome) 5, 6

By following this structured approach to diagnosis, clinicians can accurately identify orthostatic hypotension and distinguish between its various types, leading to appropriate management strategies that can reduce morbidity and mortality associated with this condition.