Postural (orthostatic) hypotension — evaluation and management

Orthostatic (postural) hypotension is defined as a drop in systolic blood pressure of 20 mmHg or more on moving from a lying to a standing position.

It occurs in about 20% of older persons. Many are asymptomatic, but the impaired physiological response still causes instability and precipitates falls.

It is more common in older adults with uncontrolled hypertension, and it is specifically in that context that it most strongly predicts falls.

Among nursing home residents it is common even when asymptomatic and is an independent risk factor for recurrent falls.

Postprandial hypotension is a separate entity: a fall in blood pressure after a meal, which worsens when the person then stands. Both orthostatic and postprandial hypotension are more common in the morning.

The ageing basis is reduced baroreflex sensitivity together with reduced vascular compliance, reduced renal sodium conservation, and blunted heart rate response.

Low cardiac output from heart failure or hypovolaemia (dehydration, acute blood loss, occult gastrointestinal bleeding).

Overtreatment with cardiovascular medication — diuretics, antihypertensives, nitrates, alpha blockers.

Autonomic dysfunction — diabetes mellitus and Parkinson’s disease; also multiple system atrophy, where fludrocortisone or midodrine may be needed for symptomatic postural hypotension. Note the textbook point that Parkinson’s disease medication itself can cause orthostatic hypotension.

Impaired venous return — venous insufficiency, varicose veins.

Prolonged bed rest with deconditioning of muscles and reflexes — a listed complication of immobility.

Drug groups to suspect in a faller: diuretics (hypovolaemia), antihypertensives (hypotension), antidepressants (postural hypotension), antipsychotics (sedation, rigidity and postural hypotension), sedatives, hypoglycaemics and alcohol. Combinations greatly increase risk. Alpha blockers are specifically associated with hip and femur fracture.

Autonomic dysfunction causing repeated falls, syncope and transient loss of consciousness may occur early in dementia with Lewy bodies, along with urinary incontinence, constipation, impotence and swallowing difficulty.

Correct measurement technique is the whole examination. Take blood pressure and pulse rate supine, after 1 minute sitting, and after 1 and 3 minutes of standing. Pathy’s assessment scale states that in older people all blood pressures need to be measured at a minimum of sitting and standing, with a check for postural hypotension at one and three minutes after standing.

Check for postprandial hypotension if the person falls, is dizzy, is syncopal, or has a stroke or myocardial infarction within two hours of a meal.

Look at the pulse response. A rise in heart rate suggests volume depletion or drug effect; failure of the heart rate to rise suggests autonomic failure or beta blockade.

Other blood-pressure pitfalls in older people: pseudohypertension from arteriosclerotic vessels (screen with the Osler manoeuvre, though sensitivity and specificity are poor); inter-arm difference — always treat the higher blood pressure; white-coat hypertension — always obtain home readings; and a wide pulse pressure carries a poor prognosis in older people.

Investigate for the cause: haemoglobin g/dL, sodium and potassium mEq/L, urea and creatinine mg/dL, blood glucose, ECG, and where indicated echocardiography and autonomic function testing. Evaluate for occult blood loss if indicated.

Non-pharmacological first. Eliminate the offending drugs or reduce the dose. Rehydrate as appropriate and evaluate for blood loss. Support (compression) stockings, leg elevation, and adaptive behaviours — pausing and getting up slowly, rising in stages. Pathy adds that compression stockings and tools around the home to aid slow rising are helpful for adults with postural hypotension.

Pharmacological for autonomic dysfunction or idiopathic cases: mineralocorticoids (fludrocortisone) and midodrine hydrochloride, in addition to support stockings and adaptive behaviour.

Additional practical measures: head-up tilt of the bed by 15–20%, a glass of water before rising (kept at the bedside overnight), liberalised salt and fluid intake where not contraindicated, small frequent low-carbohydrate meals for postprandial hypotension (acarbose is listed as useful), avoiding hot baths, large meals and alcohol, and physical counter-manoeuvres.

Do not chase the numbers. If the drop is mild and the person can understand and use non-pharmacological measures, reassurance and explanation focused on managing symptoms rather than absolute values may be all that is required.