Synopsis
Measure orthostatic physiology correctly, identify reversible contributors and recognise neurogenic autonomic failure, syncope and autonomic dysreflexia while balancing symptom control against supine hypertension and falls.
- Orthostatic hypotension is a sustained fall of at least 20 mmHg systolic or 10 mmHg diastolic within three minutes of standing or head-up tilt; larger systolic thresholds may be used when supine hypertension is present.
- Measure after adequate supine rest and again after standing, recording symptoms, pulse and exact timing. If the patient cannot stand safely, use the locally accepted lying-to-sitting modification and state the limitation.
- Ask about light-headedness, dim vision, coat-hanger neck pain, weakness, cognitive slowing, falls, syncope, meals, heat, exercise, urination and time of day. Patients with chronic autonomic failure may report fatigue rather than dizziness.
Key red flags
Recent vomiting, diarrhoea, bleeding, fever, diuresis or poor intake with thirst, weight loss and tachycardia suggests reduced circulating volume. Oedema does not exclude low effective arterial volume.
Investigation priorities
Demonstrate timing and magnitude of orthostatic change and relate it to symptoms and chronotropic response.
Management branches
Light-headedness, visual dimming, weakness, fall or transient loss of consciousness occurs during standing or soon after rising.
- Check ABCDE and glucose when acute, obtain event and witness history, ECG, injury and red flags, and measure properly timed supine and standing pressure and pulse when safe.
- Treat bleeding, dehydration, infection, arrhythmia or endocrine crisis and review medicines; route exertional, supine, cardiac or focal neurological features to emergency specialist care.
Key medicines
Midodrine for disabling neurogenic orthostatic hypotensionAn experienced prescriber may start 2.5 mg orally three times daily during waking upright hours and titrate weekly to response, commonly up to 10 mg three times daily, keeping the last dose at least four hours before bed.
Fludrocortisone for selected orthostatic hypotensionWhen specialist or experienced review supports off-label use, start 50–100 micrograms orally each morning and titrate cautiously to symptoms and monitoring rather than a normal standing-pressure target.