Orthostatic hypotension (Guidelines)

• Light headedness
• aching shoulders and neck
• anxiety
• unsteadiness
• leaning/ falling to the side
• double or blurred vision
• nausea
• headache
• ‘might black out’ or has blacked out
• pale or sweaty
• palpitations
• dyspnoea.

Unfortunately the history in syncope can be unreliable, with amnesia of the event and with limited symptoms, even with severe orthostatic hypotension.

Diagnostic criteria by history in syncope:

• Vasovagal syncope: is highly probable if syncope is precipitated by pain or fear or standing, and is associated with typical progressive prodrome ie pallor, sweating, nausea
• Situational Syncope: also known as reflex syncope, is highly probable if syncope occurs during or immediately after specific triggers ie during or immediately after urination, defaecation, cough or swallowing
• Orthostatic Hypotension: confirmed when syncope occurs while standing and there is concomitant significant orthostatic hypotension

Differential diagnosis

Orthostatic hypotension is the result of baroreflex failure (autonomic failure), end-organ dysfunction, or volume depletion. Injury to any limb of the baroreflex causes neurogenic orthostatic hypotension. Although, with afferent lesions alone, the hypotension tends to be modest and accompanied by wide fluctuations in blood pressure, including severe hypertension.

Drugs can produce orthostatic hypotension by interfering with the autonomic pathways or their target end-organs or by affecting intravascular volume.

Brain hypoperfusion, resulting from orthostatic hypotension from any cause, can lead to symptoms of orthostatic intolerance (for example, light-headedness imbalance and falls) and, if the hypotension is severe, to syncope. It may be asymptomatic however, up until the point of syncope.

It is important to establish if the presentation is acute or chronic.

• Eg: is it an indicator of acute hypovolaemia, or chronic and potentially related to other medical conditions, including diabetes or Parkinson’s.

Related conditions

Causes of autonomic dysfunction are adrenal insufficiency, diabetes, Parkinson’s and the atypical Parkinson’s conditions, spinal injury, primary autonomic failure, paraneoplastic disease. Orthostatic hypotension and POTS are recognised as symptoms of long covid. 

Medication

Drugs can contribute to orthostatic hypotension, in particular antihypertensives and some antidepressants. Refer to the list of medicines which can contribute to falls: Post-fall medication review (Guidelines)

Examination:

• Consider other factors related to falls in general: Observe mobility/ balance/ level of anxiety (related to fear of falling or symptoms).
• Lying and standing blood pressure. Preferably daily if an inpatient. Sit to stand if realistically the only viable option.

Investigations to consider:

• U&Es, FBC, Blood glucose
• TFTs, B12 can be considered if diagnosis is uncertain
• Morning (9am) cortisol, if suspicion of adrenal insufficiency
• ECG

Other investigations: 

• Echo, if clinical evidence of structural heart disease (eg heart failure or valvular pathology)
• Ambulatory ECG monitoring for patients with suspected cardiac arrhythmia (eg sudden loss of consciousness with prompt recovery, unrelated to posture and especially if occurring when supine.
  See: ESC Guidelines on Syncope (Diagnosis and Management of)
• Consider use of Tilt table +/- CSM, if ongoing, unexplained, recurrent syncope of uncertain cause that is refractory to initial medical management, with a suspected reflex or delayed OH aetiology and where the result would alter management. Consider
  CSM as part of the protocol

Risk stratification at the initial evaluation

Adapted from: ESC Guidelines on Syncope (Diagnosis and Management of)

Transient loss of consciousness (TLOC)

Blanket copyright permission from: ESC Guidelines on Syncope (Diagnosis and Management of)

When orthostatic hypotension is confirmed as definite or highly likely (other possibilities excluded)

First consider how significant the issue of orthostatic hypotension is

• If mild and patient can understand the situation and use non-pharmacological measures to manage the symptoms, then no further action may be necessary.
• Provide reassurance and explanation, with focus on managing symptoms more than absolute numbers.

Volume expansion

• Fluids: glass of water to take prior to rising (leave at bedside the night before).
• Slow to rise and rising in stages first thing in morning.
• Increased salt (dietician advice on real measures to achieve this).

Postural manoeuvres

• Head up tilt in bed, 15 to 20% elevation of head of bed.
• Clenching hands, tensing leg muscles prior to standing, leg crossing when standing.
• Avoid manoeuvres which may replicate valsalva, eg, straining at stool.

Compression

• Full length compression stockings.
• Counter pressure manoeuvres.
• Compression ‘garments’, if suitable.

Environmental/ lifestyle

• Maintain activity levels.
• Avoid alcohol.
• Avoid large meals in warm rooms (due to vasodilation and splanchnic pooling), drink water 15 minutes before or with meals and delay rising immediately after meals.
• Avoid hot showers & baths, and being outdoors on warm days.

Supine hypertension

This is sometimes a concern. General advice is to avoid lying supine in the day time, to eat a large carbohydrate snack before bed and consider applying a wheat bag/hot water bottle to the abdomen (ensure suitable clothing / padding to avoid burns).

There is some evidence supporting prescribing low dose anti-hypertensives at bed time.

The balance of symptomatic orthostatic hypotension versus supine hypertension is a complex and should be considered on an individual basis. Often, avoiding falls and injury which is the most immediate concern.

Medication review

Review the patient's medications following the Polypharmacy guidance: 7 Steps | Right Decisions medication review. rescribed to avoid iatrogenic cause and as part of good pharmacological management. Specifically for antihypertensive medication: see the DANTE study

Consider if there is a potential to temporarily withhold medication and observe response, or can it be discontinued more permanently? Care may be required to avoid withdrawal reactions for some medication.

Be alert to ACE inhibitors and ARBs, alpha blockers, β Blockers, antidepressants, antipsychotics, benzodiazepines, diuretics, opiates, calcium channel blockers, Parkinson’s medication, sildenafil.

There are two licensed medicines for orthostatic hypotension: 

Midodrine:

See: Midodrine hydrochloride | Drugs | BNF | NICE and Vasoconstrictor sympathomimetics (Formulary)

• Alpha adrenergic agonist, and sympathomimetic.
• Indication: Severe orthostatic hypotension when other factors excluded.
• Significant contraindications and cautions with use (see BNF).
• Dose: Initiate at 2.5mg and increase gradually. Last dose: 5pm to prevent supine hypertension.

Fludrocortisone:

See: Fludrocortisone acetate | Drugs | BNF | NICE and Mineralocorticoid therapy (Formulary)

• Indication: Orthostatic hypotension
• Off label indication
• Adverse effects: hypertension, oedema, cardiac enlargement, congestive heart failure
• Risks: potassium loss and hypokalaemic alkalosis. Therefore monitoring of BP, weight, clinical signs of fluid retention and electrolytes is required.
• Dose: 100 to 400 micrograms in neurogenic orthostatic hypotension. Increase dose gradually over weeks and months.

The BNF states that fludrocortisone has insignificant glucocorticoid activity. Local Endocrinology consultant advice is that it is not appropriate to provide steroid cards or advise to increase the dose in acute illness.

Other pharmacological treatments can be tried, but have limited evidence to support their use:

Pyridostigmine:

• Side effects of abdominal cramps, diarrhoea, tearing, salivation, Nausea and vomiting.

Erythropoietin

• Has been used when anaemia of chronic disease is associated.

Domperidone

• Potential use in managing orthostatic hypotension in the treatment for Parkinson's disease (most specifically when introducing the dopamine agonist apomorphine).

Metoclopramide

• Low evidence.

• NHS Lothian: Advice for patients who tend to faint

• ACEi: Angiotensin-converting-enzyme inhibitors 
• AF: Atrial fibrillation
• ARBs: Angiotensin receptor blocker
• BP: Blood pressure
• CSM: Carotid sinus massage
• ECG: Electrocardiogram
• POTS: Postural tachycardia syndrome