- History of symptoms of orthostatic intolerance with or without systemic symptoms
- Correlation of symptoms with a sustained increase in upright heart rate by at least 30 beats/minute (40 beats/minute for patients under the age of 20 years) within 10 minutes of standing or head-up tilt, without orthostatic hypotension
- Autonomic testing to correlate symptoms with heart rate changes, confirm the diagnosis, and assess the degree of objective signs of orthostatic intolerance
- Other diagnostic testing as needed to exclude alternative diagnoses or confounding concomitant conditions
Diagnosis
Diagnostic testing for POTS includes autonmoic testing
- Tilt table. Testing using a tilt table provides objective evidence of orthostatic intolerance in patients with lightheadedness. It increases the diagnostic yield of assessing tachycardia in patients with POTS and helps exclude orthostatic hypotension. During passive head-up tilt-table testing, full activation of the leg muscles is not needed to support the weight of the body. Thus, it is possible to assess the hemodynamic response to the downward translocation of blood volume without the compensatory influence of the skeletal muscle pump, which may conceal objective signs of orthostatic intolerance during bedside assessment. Testing should include noninvasive beat-to-beat measurement of both heart rate and blood pressure during tilt-table testing, which provides more precise information than does bedside examination. This requires referral to a cardiologist. [1]
- Sudomotor testing is abnormal in half of all people with POTS. Sudomotor testing is used in the clinical setting to evaluate and document neuropathic disturbances. The quantitative sudomotor axon reflex test (QSART), thermoregulatory sweat test (TST), sympathetic skin responses, and silastic sweat imprints are tests of sympathetic cholinergic sudomotor function. All of these tests measure post-ganglionic sudomotor function. [5]
What is sudorimetry and where is it done?
Recently, a newer sudomotor function technology (Sudoscan) has become available and adds a new tool to test at point of care in the clinic when autonomic testing had been previously restricted to specialized neurological laboratories. [6]
Treatment
Treatment of POTS includes diet, exercise and medications.
Diet
More water, more salt; avoid alcohol and caffeine. Frequently drink fluids throughout the day. For most patients, 2-2.5 liters of fluids a day is ideal. Also increase salt update . These diet changes help keep water in the bloodstream which allows more blood to reach the brain and heart. Certain things should be avoided such as alcohol and caffeine. [3]
Exercise
Physical therapy can help with POTS. Physical therapy should start slowly and progress gradually because exercise can worsen symptoms. Exercise intensity can increase as blood circulation improves through medication and diet. [3]
Medication
There is no single medication to treat patients with POTS. The medications that are used may focus on improving blood volume, helping the kidneys retain sodium, reducing heart rate or blocking the effect of adrenal hormones on the heart, and improving blood vessel constriction. [3]
Beta blockers in POTS
Beta adrenergic receptor antagonists can blunt elevations in heart rate and are therefore used frequently in patients with POTS. Propranolol and metoprolol have been studied the most in POTS but have not been compared, and there is no consensus as to whether a beta-1 selective or nonselective beta blocker is superior in the treatment of POTS. For some patients, fatigue is a limiting side effect.
- Metoprolol 0.25 to 0.5 mg/kg given twice daily reduced symptoms in nearly 80 percent of children and adolescents in a systematic review of 249 patients. [1]
- Propranolol was effective at 20 mg daily in attenuating both tachycardia and symptom burden in a study of 54 patients. A higher dose of 80 mg elicited a greater reduction in heart rate but with less net improvement of symptoms. [1]
