Postural hypotension in the elderly — evaluation and management

Definition and prevalence. Orthostatic (postural) hypotension is a sustained fall in systolic blood pressure of at least 20 mmHg, or in diastolic pressure of at least 10 mmHg, within 3 minutes of standing (or of head-up tilt to 60°). Variants: initial OH (a transient fall within 15 seconds), delayed OH (beyond 3 minutes, requiring prolonged standing or tilt to detect), and post-prandial hypotension (a fall within 2 hours of a meal). It is very common: a postural fall of more than 20 mmHg is found in about 30% of a large elderly population, and a fall of more than 40 mmHg in 10%. Baroreceptor responses become more sluggish with age, giving an increased tendency to postural syncope.

Causes — drugs first. Drugs are the commonest and most reversible cause. Implicated agents include ganglion blockers, diuretics, phenothiazines, antihistamines, antidepressants, benzodiazepines, barbiturates and antiparkinsonian drugs; cardiovascular drugs are particularly important — nitrates, beta-blockers and nifedipine — and donepezil may increase the risk of syncope. Also alpha-blockers, ACE inhibitors, ARBs, opioids and alcohol. Non-neurogenic causes: volume depletion (dehydration, haemorrhage, diarrhoea, vomiting, poor oral intake), sepsis, anaemia, adrenal insufficiency, prolonged bed rest and deconditioning, varicose veins, and haemodialysis — orthostatic hypotension and syncope are common in the elderly following haemodialysis. Neurogenic causes: autonomic neuropathy (diabetes, amyloidosis, Guillain–Barré, Shy–Drager/multiple system atrophy), Parkinson's disease, dementia with Lewy bodies, pure autonomic failure and spinal cord disease, particularly traumatic cervical cord lesions.

Clinical features. Light-headedness, dizziness, blurred or tunnel vision, "coat-hanger" ache across the neck and shoulders, generalised weakness, fatigue and cognitive slowing on standing, progressing to presyncope and syncope. In the older patient the presentation is frequently NOT dizziness but unexplained falls, drop attacks, transient confusion or functional decline, with no recall of loss of consciousness — so orthostatic hypotension must be actively sought in every faller. Symptoms are typically worst on rising in the morning, after meals, in hot weather, after exertion, after alcohol, and during intercurrent illness.

Evaluation. Measure blood pressure and heart rate supine after 5 minutes rest, then at 1 and 3 minutes of standing; extend to 5–10 minutes if delayed OH is suspected. A compensatory rise in heart rate suggests a non-neurogenic cause such as volume depletion, whereas a blunted or absent heart rate response suggests neurogenic autonomic failure. Perform a head-up tilt table test if standing measurements are negative but the history is suggestive. Take a complete drug history and examine for dehydration, anaemia, parkinsonism, peripheral neuropathy and cognitive impairment. Investigations: full blood count, urea, electrolytes, creatinine, glucose and HbA1c, B12, morning cortisol or short Synacthen test, thyroid function, ECG and, where relevant, serum and urine electrophoresis for amyloid. Exclude treatable conditions such as Addison's disease. Screen for supine hypertension, which frequently coexists and complicates treatment.

Non-pharmacological management — always first. Review the medication; it is not always possible to discontinue the relevant drugs — for example in Parkinson's disease the effect of dopaminergic drugs in aggravating the postural fall must be balanced against their therapeutic benefit. Then: avoid factors causing vasodilatation — high temperatures, marked exertion and alcohol; eat small frequent meals rather than large ones (to limit post-prandial splanchnic pooling), and reduce refined carbohydrate; avoid dehydration and liberalise salt and fluid intake where not contraindicated. Change posture slowly and reverse the change temporarily if symptoms supervene. Teach physical counter-manoeuvres — crossing the legs, tensing the calf muscles and abdominal compression, which transiently ameliorate symptoms. Elastic compression stockings (or an abdominal binder) contribute significantly, though patients may need help putting them on and they are hard to tolerate in hot weather. Sleeping with a slight head-up tilt helps, possibly by expanding plasma volume, but more than about 10° is poorly tolerated. Encourage patients to remain as active as possible, since chronic exposure to low blood pressure appears to improve cerebral autoregulation.

Drug treatment. Add only if the above measures fail. Most drugs are used outside their licence and the benefits may be limited. Fludrocortisone 100–200 µg at night is usually started first, acting by salt and water retention — monitor for hypokalaemia, oedema, heart failure and supine hypertension. Ephedrine, a sympathomimetic, can be added at 15 mg three times daily, increasing if necessary to 30 mg three times daily; higher doses cause tremor, tachycardia and agitation. Other agents used include midodrine (an α -agonist, given three times daily 1 with the last dose at least 4 hours before lying down), desmopressin for nocturnal polyuria and morning postural hypotension, and erythropoietin where there is anaemia. Supine hypertension is the main risk of all drug treatment — manage it by head-up sleeping, avoiding daytime recumbency, and a short-acting nocturnal antihypertensive if needed. Cardiac pacing does not help. Finally, because the risks of serious injury from falls are very high in this population, the patient must understand the risks and take precautions to avoid attacks wherever possible.

The 2024 ESC hypertension guideline makes routine screening for orthostatic hypotension a standard part of hypertension assessment in older adults, recommending that standing blood pressure be measured at every visit and that treatment be titrated to the standing rather than the seated pressure where postural symptoms exist. Importantly, it also states that orthostatic hypotension is not in itself a reason to leave hypertension untreated — analyses from SPRINT and pooled trial data showed that intensive blood pressure lowering did not increase orthostatic hypotension with symptoms, and that treating the underlying hypertension often improves rather than worsens orthostatic tolerance. In parallel, the AGS Beers Criteria 2023 continue to list drugs to avoid in patients with a history of syncope or falls, reinforcing medication review as the first therapeutic step.