Supine Hypertension with Orthostatic Hypotension

Supine hypertension with orthostatic hypotension is the combination of a high blood pressure when lying (systolic 150 mmHg or more or diastolic 90 mmHg or more) and an excessive fall on standing (systolic 20 mmHg or more or diastolic 10 mmHg or more within 3 minutes). It is typical of neurogenic orthostatic hypotension.

It affects about half of people with neurogenic orthostatic hypotension, such as Parkinson disease, multiple system atrophy, pure autonomic failure and diabetic autonomic neuropathy. The risk is higher in older people.

Pathophysiology. Impaired baroreflex and sympathetic vasoconstriction allow pooling and a fall in pressure on standing. Lying down, residual sympathetic tone, fluid redistribution and pressor drugs cause pressure to rise without a counter regulatory response. Overnight pressure natriuresis then causes volume depletion and worsens the morning fall.

Dizziness, visual blurring, neck and shoulder pain ("coat hanger" pain), fatigue and syncope on standing, worst in the morning, after meals and in heat. Supine hypertension is often asymptomatic, though headache can occur. It increases left ventricular hypertrophy, kidney damage and stroke.

Measure blood pressure and heart rate after 5 minutes of lying, then at 1 and 3 minutes of standing. Use 24-hour ambulatory monitoring to document nocturnal hypertension. Test for causes: drugs, diabetes, amyloidosis, vitamin B12 deficiency, and autonomic testing. A heart rate rise of under 15 beats/min on standing suggests a neurogenic cause.

Differential diagnosis.

• Non-neurogenic orthostatic hypotension from dehydration, haemorrhage or drugs.
• Essential hypertension with drug induced orthostatic hypotension.
• Phaeochromocytoma and adrenal insufficiency.

Avoid lying flat during the day and sleep with the head of the bed raised by 30 degrees. Stop unnecessary vasoactive drugs. Use compression garments, high fluid and salt intake if tolerated, and counter manoeuvres.

Treat orthostatic hypotension with midodrine 2.5 to 10 mg three times daily, with the last dose at least 4 hours before bed, fludrocortisone 0.05 to 0.2 mg daily (it worsens supine hypertension), or droxidopa 100 to 600 mg three times daily with the last dose at least 3 hours before bed.

For supine hypertension, use a short acting agent at bedtime, such as losartan 25 mg, captopril 25 mg or a glyceryl trinitrate patch 0.1 mg/hour removed on waking.

Monitoring. Seated, supine and standing pressures, falls, renal function and potassium on fludrocortisone.