Orthostatic Syncope: Definition, Mechanisms, and Management

Diagnosis

• Orthostatic syncope is a temporary loss of consciousness caused by cerebral hypoperfusion that occurs when assuming an upright position due to a significant drop in blood pressure without adequate compensatory mechanisms, as defined by the European Heart Journal 1, 2
• Classical Orthostatic Hypotension (OH) is defined as a sustained decrease in systolic BP ≥20 mmHg, diastolic BP ≥10 mmHg, or a sustained decrease in systolic BP to an absolute value <90 mmHg within 3 minutes of standing or head-up tilt, according to the European Heart Journal 2
• In cases of supine hypertension, a systolic BP drop ≥30 mmHg should be considered significant, as stated by the European Heart Journal 2
• Orthostatic heart rate increase is typically blunted (<10 bpm) in neurogenic OH due to impaired autonomic control, as reported by the European Heart Journal 2
• Initial Orthostatic Hypotension is characterized by a BP decrease on standing of >40 mmHg for systolic BP and/or >20 mmHg for diastolic BP within 15 seconds of standing, as defined by the European Heart Journal 1
• Delayed Orthostatic Hypotension is defined as OH occurring beyond 3 minutes of head-up tilt or active standing, according to the European Heart Journal 1

Clinical Presentation

• Symptoms of orthostatic syncope include dizziness, lightheadedness, weakness, fatigue, lethargy, as reported by the European Heart Journal and the Journal of the American College of Cardiology 1, 4
• Visual disturbances, such as blurring, enhanced brightness, and tunnel vision, can occur in patients with orthostatic syncope, as stated by the European Heart Journal and the European Heart Journal 1, 3
• Hearing disturbances, such as impaired hearing, crackles, and tinnitus, can also occur in patients with orthostatic syncope, as reported by the European Heart Journal and the European Heart Journal 1, 3

Management

• The American College of Cardiology recommends increasing daily fluid intake to 2-3 liters as a non-pharmacological intervention for orthostatic syncope, as stated by the Journal of the American College of Cardiology and Praxis Medical Insights 5, 6
• The American College of Cardiology suggests increasing salt consumption (5-10g daily) as a non-pharmacological intervention for orthostatic syncope, as reported by the Journal of the American College of Cardiology and Praxis Medical Insights 5, 6
• Physical counter-pressure maneuvers, such as leg-crossing, squatting, and muscle tensing, can be beneficial in managing orthostatic syncope, as stated by the Journal of the American College of Cardiology and Praxis Medical Insights 5, 6
• Compression garments, such as waist-high compression stockings, can be used to manage orthostatic syncope, as reported by the Journal of the American College of Cardiology and Praxis Medical Insights 5, 6
• Elevation of the head of the bed during sleep can help manage orthostatic syncope, as suggested by Praxis Medical Insights 5
• Fludrocortisone is recommended as a first-line treatment for volume expansion in patients with hypovolemic OH, as stated by the Journal of the American College of Cardiology and Praxis Medical Insights 5, 6
• Midodrine (2.5-10 mg three times daily) can be used to enhance vascular tone in patients with orthostatic syncope, as reported by Praxis Medical Insights and the Journal of the American College of Cardiology 5, 6
• Droxidopa can be beneficial in patients with syncope due to neurogenic OH, as stated by the Journal of the American College of Cardiology 6
• Pyridostigmine may be beneficial in patients refractory to other treatments, as reported by the Journal of the American College of Cardiology 6
• Octreotide may be beneficial in patients with refractory recurrent postprandial or neurogenic OH, as stated by the Journal of the American College of Cardiology 6

Special Considerations

• The American College of Cardiology recommends reducing or withdrawing medications that may cause hypotension (vasoactive drugs and diuretics) in patients with orthostatic syncope, as stated by the Journal of the American College of Cardiology and Praxis Medical Insights 5, 6
• Monitoring for supine hypertension with vasoconstrictors like midodrine is essential in patients with orthostatic syncope, as reported by Praxis Medical Insights 5
• Midodrine should be used with caution in older males due to potential urinary outflow issues, as stated by Praxis Medical Insights 5
• Fluid resuscitation via oral or intravenous bolus can be used for acute dehydration in patients with orthostatic syncope, as reported by the Journal of the American College of Cardiology and Circulation 6, 7
• Physical counter-maneuvers during symptomatic episodes can help manage orthostatic syncope, as stated by the Journal of the American College of Cardiology and Praxis Medical Insights 5, 6