POTS is a disorder that affects the autonomic nervous system, which is the part of the nervous system that controls blood pressure, heart rate, breathing rate, and digestion. It used to be called by many other names including mitral valve prolapse syndrome, chronic orthostatic intolerance, and neurocirculatory asthenia.
Symptoms include dizziness with standing, fatigue, palpitations, exercise intolerance, cognitive difficulties, fainting, blurry vision, trouble breathing, leg heaviness, and an unusual mottling in the legs when standing (believed to be due to poor circulation). It can be mild in some patients, but in others it is severe enough to interfere with their jobs and family life.
The diagnosis of POTS requires:
- An increase in heart rate of at least 30 beats per minute within 10 minutes of going from a lying position to standing (patients aged 20 and older).
- For those aged 12-19, the heart rate increase should be over 40 beats per minute.
- Symptoms worse with upright posture, and improve with lying down.
- Symptoms for at least 6 months
Tilt table testing, and autonomic testing help make the diagnosis. Laboratory testing, imaging, and other investigations may be undertaken to evaluate for disorders that can masquerade as, or co-exist with, POTS.
POTS can co-exist with conditions like Ehlers-Danlos syndrome, mast cell activation syndrome, chronic fatigue syndrone, fibromyalgia, and irritable bowel syndrome. In my experience, it can often co-exist or be confused for other vestibular disorders, particularly vestibular migraine, and it can take an experienced oto-neurologist to evaluate a patient for other vestibular disorders.
The following measures can be taken to help alleviate POTS:
- Ensuring adequate hydration to improve blood volume
- Increasing salt intake
- Compression garments
- Eating small frequent meals (instead of large meals)
- Avoiding alcohol, caffeine, and high-carb foods
- Limiting exposure to hot environments
- Exercise to build endurance
There are no FDA-approved treatments for POTS. Some medications that can be used include beta-blockers, midodrine, fludrocortisone, and pyridostigmine.