Orthostatic Hypotension and Orthostatic Syncope

Background

• Orthostatic syncope is a transient loss of consciousness due to cerebral hypoperfusion after standing from a supine or sitting position, followed by spontaneous recovery without neurologic sequelae.
• Orthostatic hypotension is a reduction in systolic blood pressure due to orthostatic stress that may be symptomatic or asymptomatic. It is common in older patients and may result in syncope. Definitions include
  • a ≥ 20-mm Hg decrease in systolic blood pressure or a ≥ 10-mm Hg decrease in diastolic blood pressure immediately after standing or after 3 minutes of standing compared to a sitting or supine position
  • a decrease in systolic blood pressure ≥ 30 mm Hg in patients with hypertension (supine systolic blood pressure ≥ 160 mm Hg)
• Common causes include illness, autonomic dysfunction, volume depletion, cardiovascular impairment, endocrine dysfunction, and drugs including
  • alcohol
  • antihypertensives
  • antiadrenergics
  • anticholinergics
  • antianginals
  • antiarrhythmics in older patients
  • antidepressants

Evaluation

• Suspect orthostatic syncope with symptoms of lightheadedness, dizziness, or visual disturbances within minutes of standing, followed by syncope and spontaneous recovery in a supine position.
• Symptoms may sometimes be delayed up to 30 minutes after a positional change (delay in symptoms can also occur in reflex syncope, but absence of bradycardia helps distinguish orthostatic syncope from reflex syncope).
• Consider other diagnoses if there is a confusional state, tonic-clonic jerking, palpitations, or dyspnea.
• Assess blood pressure and pulse in lying and supine positions, immediately after standing, and after standing for ≥ 1 minute (active standing test).
• Diagnose orthostatic changes if systolic blood pressure decreases by > 20 mm Hg, diastolic blood pressure decreases by > 10 mm Hg, or pulse increases by > 30 beats/minute.
• Consider tilt-table testing if there is high clinical suspicion for orthostatic syncope but a negative active standing test.
• Obtain resting electrocardiogram for all patients with syncope to identify cardiac arrhythmias (Strong recommendation).
• Avoid additional testing (such as brain imaging) to diagnose orthostatic syncope if the episode is related to assuming a standing position, there is documentation of orthostatic hypotension, and the neurologic exam is normal (Strong recommendation).

Management

• Educate the patient on warning signs and avoiding triggers such as specific medications, dehydration, rising too quickly (especially in the morning), and prolonged standing.
• Consider adequate hydration and sodium supplementation in adult patients without underlying hypertension, heart failure, or edema (Weak recommendation).
• Consider exercises to strengthen and maintain postural tone such as isometric muscle contractions when changing position.
• Consider lower extremity or abdominal binders in patients with pooling issues.
• Only consider medications in rare patients who fail conservative nonpharmacological therapy (Weak recommendation).
• Medication options include:
  • fludrocortisone 0.1-0.2 mg orally daily
  • midodrine 2.5 mg orally 3 times daily, titrated by 2.5 mg/day weekly up to 10 mg orally 3 times daily
  • droxidopa 100 mg orally 3 times daily, titrated every 24-48 hours as needed up to maximum dose of 1,800 mg/day orally in 3 divided doses
  • pyridostigmine 30 mg orally 2-3 times daily, titrated up to 60 mg orally 3 times daily
  • Other medications have been used in cases refractory to the above measures, but lack consistent evidence of efficacy or benefit.