What is the workup and treatment for a patient with orthostatic hypotension?

Workup and Treatment of Orthostatic Hypotension

The comprehensive management of orthostatic hypotension requires both thorough diagnostic evaluation to identify the underlying cause and a stepwise treatment approach starting with non-pharmacological measures before progressing to medications such as midodrine, fludrocortisone, or droxidopa. 1, 2

Diagnostic Workup

• Measure blood pressure after 5 minutes of sitting/lying and then at 1 and/or 3 minutes after standing to confirm orthostatic hypotension (defined as a decrease in systolic BP ≥20 mmHg or diastolic BP ≥10 mmHg within 3 minutes of standing) 2, 3
• When standard orthostatic vital signs are nondiagnostic but clinical suspicion remains high, head-up tilt-table testing can confirm the diagnosis and assess treatment response 4, 3
• Evaluate for reversible causes including:
  • Medication effects (diuretics, vasodilators, antidepressants, antipsychotics) 1, 3
  • Volume depletion (dehydration, blood loss) 4
  • Neurogenic causes (multiple system atrophy, Parkinson's disease, pure autonomic failure, diabetic neuropathy) 1, 5
  • Cardiovascular disorders affecting cardiac output 4
  • Endocrine disorders (adrenal insufficiency, diabetes) 4, 3

Non-Pharmacological Management

• Increase fluid intake (aim for 2-3 liters daily) and salt consumption (6-9g daily) if not contraindicated by other conditions 1, 2
• Implement physical counter-maneuvers during symptom onset:
  • Leg crossing, muscle tensing, squatting, and stooping 1, 2, 6
• Recommend compression garments (at least thigh-high and preferably including the abdomen) 1, 6
• Advise acute water ingestion (≥480 mL) for temporary relief, with peak effect occurring 30 minutes after consumption 1, 2
• Suggest smaller, more frequent meals to reduce post-prandial hypotension 2, 6
• Elevate the head of the bed during sleep (helps prevent supine hypertension) 2
• Encourage physical activity and exercise to avoid deconditioning 2, 6

Pharmacological Management

• Consider pharmacological treatment when non-pharmacological measures fail to adequately control symptoms 2
• First-line medications include:
  • Midodrine: An alpha-1 agonist that increases vascular tone; initial dose 2.5-5mg three times daily (last dose before 6 PM to avoid supine hypertension); can increase standing systolic BP by 15-30 mmHg for 2-3 hours 1, 7
  • Fludrocortisone: Initial dose 0.05-0.1mg daily, titrated to 0.1-0.3mg daily; works by increasing plasma volume; monitor for supine hypertension, hypokalemia, edema, and heart failure 1, 2
  • Droxidopa: Improves symptoms in neurogenic OH due to Parkinson disease, pure autonomic failure, and multiple system atrophy; may reduce falls 1, 2

Special Considerations

• For patients with both hypertension and orthostatic hypotension, consider long-acting dihydropyridine calcium channel blockers or RAS inhibitors as first-line therapy 2
• For diabetic patients with orthostatic hypotension, assess for cardiovascular autonomic neuropathy 2
• Monitor for supine hypertension (BP>200 mmHg systolic), a common adverse effect of midodrine and other pressor agents 7
• For non-responders to monotherapy, consider combination therapy with midodrine and fludrocortisone 2
• Treatment goals should focus on improving symptoms and functional capacity rather than achieving a target blood pressure 3, 8

Pitfalls and Caveats

• Midodrine should only be continued in patients who report significant symptomatic improvement 7
• Avoid taking the last dose of midodrine after 6 PM to prevent supine hypertension during sleep 1, 7
• Regular monitoring for adverse effects is essential, especially supine hypertension with pressor agents and electrolyte abnormalities with fludrocortisone 1, 2
• Patients on hemodialysis should be aware that midodrine is removed by dialysis 7
• Acute water ingestion for temporary relief is not intended for routine or long-term use 1