What is the management plan for a patient with recurrent syncope and orthostatic intolerance, diagnosed via a positive head-up tilt table test, with normal cardiac investigations?

Management of Recurrent Syncope with Positive Tilt Table Test (Vasovagal Syncope)

For this patient with recurrent vasovagal syncope confirmed by tilt table testing, the correct management is: increased salt intake (6-9 g/day), increased fluid intake (2-3 L/day), and physical counter-pressure maneuvers (squatting) when symptomatic. 1 Restricting fluids is contraindicated and would worsen the condition. 1

Core Non-Pharmacological Management (First-Line)

Patient Education and Lifestyle Modifications

• Patient education about the benign prognosis of vasovagal syncope is the foundation of treatment (Class I recommendation). 1
• Increase salt intake to 6-9 g (100-150 mmol) per day unless contraindicated by hypertension, renal disease, or heart failure. 1
• Increase fluid intake to 2-3 liters per day to expand blood volume. 1
• Instruct patients to assume a supine position immediately when prodromal symptoms begin to prevent syncope and injury. 1

Physical Counter-Pressure Maneuvers (Class IIa)

• Teach leg crossing with muscle tensing, hand grip, or squatting when prodromal symptoms occur - these maneuvers increase blood pressure by 15-30 mmHg and can abort impending syncope. 1
• These maneuvers require a sufficiently long prodrome to be effective and reduce syncope recurrence by 39% compared to conventional therapy alone. 1
• The patient's reported lightheadedness during tilt testing suggests adequate prodromal warning time, making these maneuvers appropriate. 1

Pharmacological Management (Second-Line)

Midodrine (Class IIa)

• Midodrine is reasonable for patients with recurrent vasovagal syncope who fail conservative measures and have no history of hypertension, heart failure, or urinary retention. 1, 2
• Midodrine is an alpha-1 agonist that increases peripheral vascular tone and standing blood pressure by 15-30 mmHg at 1 hour post-dose. 1, 2
• Meta-analysis shows 43% reduction in syncope recurrence with midodrine. 1
• Midodrine should NOT be started "regularly" as initial therapy - it is reserved for patients with inadequate response to conservative measures. 1, 2
• Monitor for supine hypertension (can exceed 200 mmHg systolic); last dose should not be taken after 6 PM. 2

Fludrocortisone (Class IIb)

• Fludrocortisone might be reasonable for patients with inadequate response to salt and fluid intake, though evidence is limited. 1
• Monitor serum potassium due to risk of hypokalemia. 1

Critical Management Errors to Avoid

NEVER Restrict Fluids

• Fluid restriction is absolutely contraindicated in vasovagal syncope - it worsens hypovolemia and increases syncope risk. 1
• The concern about "hyponatremia" from increased fluid intake is unfounded when combined with increased salt intake. 1

Avoid Premature Pharmacotherapy

• Do not start midodrine or other medications before attempting conservative measures (education, salt/fluid, physical maneuvers). 1
• Most patients respond adequately to non-pharmacological interventions alone. 1

Treatment Algorithm

1. Initial Management (All Patients):

   • Patient education about diagnosis and benign prognosis 1
   • Increase salt (6-9 g/day) AND fluid (2-3 L/day) 1
   • Train in physical counter-pressure maneuvers 1
   • Instruct to lie down immediately when prodrome begins 1

2. If Inadequate Response After 4-8 Weeks:

   • Consider midodrine 2.5-10 mg three times daily (if no contraindications) 1, 2
   • Consider fludrocortisone 0.1-0.2 mg daily (monitor potassium) 1

3. Refractory Cases:

   • Consider tilt training (standing against wall 30-60 minutes daily), though compliance is poor and evidence is mixed (Class IIb) 1, 3
   • Beta-blockers might be reasonable if patient is ≥42 years old (Class IIb) 1

Special Considerations for This Patient

• The positive tilt test with glyceryl trinitrate (nitrate-potentiated) confirms vasovagal syncope diagnosis. 1, 4
• Normal cardiac investigations (24-hour ECG, echocardiogram) appropriately exclude cardiac causes. 1
• The patient's young age (female) and recurrent nature suggest typical vasovagal syncope pattern. 1
• Begin with conservative measures; reserve midodrine for treatment failures only. 1, 2