Diagnosis of orthostatic hypotension

If orthostatic hypotension is suspected:

• measure supine blood pressure (BP) and heart rate after 5 minutes of quiet rest
• remeasure BP and heart rate immediately on standing, and after 3 minutes.

Orthostatic hypotension is diagnosed if there is a fall in systolic BP of at least 20 mmHg or diastolic BP of at least 10 mmHg within 3 minutes of standing.

If orthostatic hypotension is present, lack of reflex increase in heart rate may indicate predominant autonomic failure. Conversely, an exaggerated heart rate response (eg an increase of more than 30 beats per minute) in the absence of orthostatic hypotension may indicate another cause for postural symptoms (eg orthostatic intolerance; see Orthostatic hypotension in young adults).

If clinical suspicion of orthostatic hypotension remains despite the absence of a demonstrable fall in clinic BP, home BP measurements or ambulatory BP monitoring can be considered. Ambulatory BP monitoring is especially useful if nocturnal supine hypertension is suspected, and for detecting delayed orthostatic hypotension, which occurs beyond 3 minutes after standing. Initial orthostatic hypotension, which occurs around 10 to 15 seconds after standing, is difficult to detect with conventional BP measurement techniques.

A combination of clinic, home and ambulatory BP measurement is usually sufficient to confirm the diagnosis of postural hypotension. Tilt testing is rarely needed and is not recommended in the elderly.