Orthostatic Intolerance Management

Introduction to Orthostatic Intolerance

• Orthostatic intolerance is characterized by symptoms such as lightheadedness, palpitations, tremulousness, generalized weakness, blurred vision, exercise intolerance, and fatigue in patients with orthostatic intolerance 1
• A detailed medical history, physical examination, family history, and 12-lead ECG should be performed in patients with suspected orthostatic intolerance, as recommended by the American College of Cardiology 1

Diagnostic Criteria and Testing

• The diagnostic criteria for Postural Orthostatic Tachycardia Syndrome (POTS) include:

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• The active standing test can be diagnostic for orthostatic intolerance, with a symptomatic fall in systolic BP ≥20 mmHg or diastolic BP ≥10 mmHg, or decrease in systolic BP to <90 mmHg, as stated in the European Heart Journal 3
• The tilt table test can be useful for pediatric patients with suspected vasovagal syncope when diagnosis is unclear, with an optimal diagnostic heart rate increase cutoff of 38 bpm 1

Associated Conditions

• Mast cell activation syndrome (MCAS) is commonly associated with POTS, with 25.2% of MCAS patients having POTS, and serum tryptase should be considered at baseline and during symptom flares, according to the American College of Cardiology 4
• Hypermobile Ehlers-Danlos syndrome (hEDS) is associated with POTS due to vascular laxity, with up to 40% of cases following viral infections, including COVID-19 4
• Autoimmune disorders have an increased prevalence in POTS patients and family members 4
• Recent infections, including post-COVID-19, are associated with POTS, as stated by the European Heart Journal 5
• Chronic fatigue syndrome is associated with POTS, according to the European Heart Journal 5

Medication Considerations

• Intranasal fluticasone does not significantly lower blood pressure or affect CSF pressure, unlike medications such as topiramate, indomethacin, candesartan, and beta blockers, according to the American Academy of Neurology 6
• Migraine preventives that reduce blood pressure, such as candesartan and beta blockers, should be used with caution in patients with orthostatic intolerance, as recommended by the American College of Cardiology 6
• The American College of Cardiology recommends low-dose beta-blockers, such as propranolol, particularly for patients with palpitations and coexisting anxiety or migraine, and suggests starting with low doses and gradually titrating 7
• Midodrine 2.5-10 mg three times daily, with the first dose taken before getting out of bed and the last dose no later than 4 pm, is recommended for patients with POTS 7
• Fludrocortisone (up to 0.2 mg taken at night) may be used in conjunction with salt loading, and patients should be monitored for electrolytes carefully, especially for hypokalemia 7
• Ivabradine may be considered for patients with severe fatigue exacerbated by beta-blockers, as it has been shown to improve heart rate and quality of life in POTS patients 7
• Non-dihydropyridine calcium-channel blockers, such as diltiazem or verapamil, may be used for palpitations in patients with POTS 7

Lifestyle Modifications

• The American College of Cardiology recommends increasing fluid intake to approximately 3L daily (100 oz, approximately 35 ml/kg) and daily sodium intake to 8-10g from all sources 8
• Increase salt intake to 10-12g daily, unless contraindicated, and maintain fluid intake of 2-3 liters of water or electrolyte-balanced fluid daily, with caution in patients with cardiac dysfunction, HF, uncontrolled hypertension, or chronic kidney disease 9, 10
• Patients with POTS should begin with recumbent or semi-recumbent exercise, such as rowing, swimming, or recumbent cycling, and start with 5-10 minutes daily at a level allowing speech in full sentences 7
• Gradually increasing duration by approximately 2 minutes per day each week is recommended for patients with POTS 7
• Elevating the head of the bed with 4-6 inch (10-15 cm) blocks during sleep is suggested for patients with POTS 7
• Physical counter-pressure maneuvers are recommended when feeling lightheaded, as suggested by the American College of Cardiology 8

Monitoring and Follow-up

• The American College of Cardiology recommends monitoring for supine hypertension when using midodrine 10
• The American College of Cardiology recommends monitoring electrolytes (sodium, potassium, magnesium) and renal function, especially for patients on fludrocortisone, and evaluating treatment response with standing heart rate and symptom improvement 8, 10, 7
• Follow-up testing is recommended every 3-6 months or when changing treatment regimens, with immediate testing during significant symptom exacerbations or when starting new medications that may affect electrolyte balance 7, 8
• Patients with POTS should seek immediate medical attention if they experience syncope, severe chest pain, sustained palpitations unrelieved by rest, shortness of breath at rest, or palpitations with dizziness, confusion, or altered mental status 11

Special Considerations

• Initiating upright exercise too soon can worsen fatigue and cause post-exertional malaise in patients with POTS 7
• Using salt tablets instead of dietary salt can cause nausea and vomiting in patients with POTS 7
• Midodrine may be reasonable for pediatric patients with vasovagal syncope not responding to lifestyle measures, according to the American Heart Association 1
• Beta blockers are not beneficial in pediatric patients with vasovagal syncope, as recommended by the American Heart Association 1
• Consider earlier referral for patients with significant quality of life impairment or syncope, as suggested by the American Heart Association 1