Cardiovascular

Postural (orthostatic) hypotension

Postural hypotension is a clinically important fall in blood pressure after standing, caused by inadequate compensation for gravitational blood pooling; it presents with postural dizziness, falls or syncope and should trigger medication, volume, cardiovascular, neurological and endocrine assessment.

In a nutshell

Postural hypotension is a clinically significant fall in blood pressure after standing, diagnosed in the NICE pathway by a systolic fall of at least 20 mmHg or diastolic fall of at least 10 mmHg after standing for at least 1 minute. Review medicines and reversible causes first, use tailored physical and falls-prevention measures, and reserve midodrine or off-label fludrocortisone for specialist-guided treatment of persistent severe symptoms.

Classic presentation

An older person becomes light-headed and unsteady every time they stand after a recent antihypertensive or diuretic change; symptoms improve on sitting, and a supine-to-standing blood-pressure measurement reproduces the symptoms and postural fall.

Key points

Use a supine baseline where possible, then measure again after standing for at least 1 minute; NICE uses a 20 mmHg systolic or 10 mmHg diastolic fall threshold.
Review medicines, dehydration, bleeding, illness, anaemia and autonomic disease rather than labelling every postural symptom as idiopathic.
If the history is suggestive but the threshold is not demonstrated, repeat from a supine baseline and consider specialist cardiovascular assessment.
In people with hypertension and symptomatic or significant postural hypotension, base treatment targets on the standing blood pressure.
Slow position changes, symptom-triggered sitting or lying, counter-pressure manoeuvres, trigger avoidance and carefully tailored fluid, salt or compression advice are foundational.
Midodrine is specialist treatment for severe autonomic orthostatic hypotension after corrective factors are addressed; supine hypertension must be monitored.
Fludrocortisone is off-label for this indication and can cause fluid retention, hypokalaemia and supine hypertension.
Recurrent, injurious or unexplained falls require a comprehensive falls assessment, not just a blood-pressure measurement.

First-line investigation

Supine and standing blood pressure with symptoms and heart rate recorded, followed by medication, volume-status, falls, cardiovascular and neurological assessment.

Management

Exclude danger and injury

Escalate shock, suspected bleeding, acute kidney injury, serious injury, exertional or supine syncope, chest pain, palpitations, breathlessness or concerning neurological features before treating the postural blood-pressure finding.^4,3

Confirm the postural pattern and cause

Measure supine blood pressure where possible, repeat after at least 1 minute standing with symptoms and heart rate recorded, then review medicines, volume status, bleeding, illness, falls and autonomic or cardiac clues.^1,4,3

Correct reversible causes and reduce falls

Adjust causative medicines safely, correct dehydration or other identified causes, advise gradual position changes and counter-pressure manoeuvres, and tailor trigger avoidance, compression, fluid and salt advice to comorbidity.^1,3,2,8

Use specialist drug treatment only when necessary

For persistent severe autonomic symptoms after corrective measures, consider specialist midodrine or selected off-label fludrocortisone with supine and standing blood-pressure, renal, electrolyte and fluid-status monitoring.^6,5,7,8

Review response and investigate persistent symptoms

Recheck symptoms and supine/standing blood pressure after medicine changes, arrange comprehensive falls assessment when indicated, and refer for cardiovascular, autonomic, geriatric or neurological assessment when measurements are inconclusive, symptoms recur or treatment is complicated by supine hypertension.^1,4,3

Exam traps

A seated reading can miss a postural drop; supine measurement is preferred by current NICE guidance when practical.
Do not diagnose from a single low standing reading without relating it to symptoms, timing and the supine baseline.
A postural drop does not exclude arrhythmia, structural heart disease, seizure or bleeding as the cause of a blackout.
Salt and fluid advice is not automatically safe in heart failure, kidney disease or hypertension.
Midodrine can cause supine hypertension and should not be treated as a routine first-line drug for all postural dizziness.
A negative bedside test with a strongly suggestive history warrants repeat or specialist assessment rather than reassurance alone.

Illustrations

Head-up tilt-table testing for orthostatic symptomsA participant secured on a head-up tilt table while blood pressure and heart rate are monitored, with a legend explaining that specialist provocation testing is used when bedside assessment is inconclusive or autonomic disease is suspected.NASA Headquarters, Wikimedia Commons · Public domain

Key sources

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.