Postural Orthostatic Tachycardia Syndrome (POTS) is a form of dysautonomia that is estimated to impact between 1,000,000 and 3,000,000 Americans, and millions more around the world. POTS is a form of orthostatic intolerance that is associated with the presence of excessive tachycardia and many other symptoms upon standing.1
The current diagnostic criteria for POTS is a heart rate increase of 30 beats per minute (bpm) or more, or over 120 bpm, within the first 10 minutes of standing, in the absence of orthostatic hypotension.1,2,3,4 In children and adolescents, a revised standard of a 40 bpm or more increase has recently been adopted.4,5 POTS is often diagnosed by a Tilt Table Test, but if such testing is not available, POTS can be diagnosed with bedside measurements of heart rate and blood pressure taken in the supine (laying down) and standing up position at 2, 5 and 10 minute intervals. Doctors may perform more detailed tests to evaluate the autonomic nervous system in POTS patients, such as Quantitative Sudomotor Axon Reflex Test (QSART, sometimes called Q-Sweat), Thermoregulatory Sweat Test (TST), skin biopsies looking at the small fiber nerves, gastric motility studies and more.
Signs and Symptoms
While the diagnostic criteria focus on the abnormal heart rate increase upon standing, POTS usually presents with symptoms much more complex than a simple increase in heart rate. It is fairly common for POTS patients to have a drop in blood pressure upon standing, but some POTS patients have no change or even an increase in blood pressure upon standing.1 POTS patients often have hypovolemia (low blood volume) and high levels of plasma norepinephrine while standing, reflecting increased sympathetic nervous system activation.3 Approxiamtely 50% of POTS patients have a small fiber neuropathy that impacts their sudomotor nerves. Many POTS patients also experience fatigue, headaches, lightheadedness, heart palpitations, exercise intolerance, nausea, diminished concentration, tremulousness (shaking), syncope (fainting), coldness or pain in the extremeties, chest pain and shortness of breath.1,3,4 Patients can develop a reddish purple color in the legs upon standing, believed to be caused by blood pooling or poor circulation. The color change subsides upon returning to a reclined position.
Quality-of-Life and Disability
Some patients have fairly mild symptoms and can continue with normal work, school, social and recreational activities. For others, symptoms may be so severe that normal life activities, such as bathing, housework, eating, sitting upright, walking or standing can be significantly limited.1,3 Physicians with expertise in treating POTS have compared the functional impairment seen in POTS patients to the impairment seen in chronic obstructive pulmonary disease (COPD) or congestive heart failure.1 Approximately 25% of POTS patients are disabled and unable to work.1 Researchers found that quality-of-life in POTS patients is comparable to patients on dialysis for kidney failure.21, 22
History of POTS
The term “POTS” was coined in 1993 by a team of researchers from Mayo Clinic, led by neurologist Dr. Philip Low.8However, POTS is not a new illness; it has been known by other names throughout history, such as DaCosta’s Syndrome, Soldier’s Heart, Mitral Valve Prolapse Syndrome, Neurocirculatory Asthenia, Chronic Orthostatic Intolerance, Orthostatic Tachycardia and Postural Tachycardia Syndrome.3 In the past, it was mistakenly believed to be caused by anxiety. However, modern researchers have determined that POTS is not caused by anxiety.2,6,7 It is caused by a malfunction of the patient’s autonomic nervous system. Thankfully, in the last 20 years, researchers have gained much more insight into imbalances of the autonomic nervous system.1
POTS researchers have classified POTS in various ways. Dr. Blair Grubb has described POTS as “primary” or “secondary.” “Primary” refers to POTS with no other identifiable medical condition (also known as “idiopathic” POTS). “Secondary” refers to POTS with the presence of another medical condition known to cause or contribute towards POTS symptoms.1 Dr. Julian Stewart has described “high flow” and “low flow” POTS, based upon the flow of blood in the patients lower limbs.9
Other researchers have described POTS based on some of its more prominent characteristics: hypovolemic POTS, which is associated with low blood volume; partial dysautonomic or neuropathic POTS which is associated with a partial autonomic neuropathy; and hyperandrenergic POTS which is associated with elevated levels of norepinephrine.1,3,4 These are not distinct medical conditions and many POTS patients have two or three of the different characteristics present. For example, one patient can have neuropathy, low blood volume and elevated norepineprhine.
Who Develops POTS?
POTS can strike any age, gender or race, but it is most often seen in women of child bearing age (between the ages of 15 and 50).2 Men and boys can develop it as well, but approximately 80% of patients are female.2
Is POTS Caused by Anxiety?
While some of the physical symptoms of POTS overlap with the symptoms of anxiety, such as tachycardia and palpitations, POTS is not caused by anxiety. POTS patients are often misdiagnosed as having anxiety or panic disorder, but their symptoms are real and can severely limit a person’s ability to function.1,3 Research has shown that POTS patients are similarly or even less likely to suffer from anxiety or panic disorder than the general public.3,5,6,7 Research surveys that evaluate mental health show similar results between POTS patients and national norms.20
What Causes POTS?
POTS is a heterogeneous (meaning it has many causes) group of disorders with similar clinical manifestations.1,4 POTS itself is not a disease; it is simply a cluster of symptoms that are frequently seen together. This is why the ‘S’ in POTS stands for “Syndrome.” Since POTS is not a disease, it is fair to say that POTS is caused by something else. However, figuring out what is causing the symptoms of POTS in each patient can be very difficult, and in many cases, patients and their doctors will not be able to determine the precise underlying cause. When doctors cannot pinpoint the underlying cause of a patient’s POTS, it may be called Primary or Idiopathic POTS.1 Idiopathic simply means “of an unknown origin.”
While researchers are still working to identify the root causes and pathology of POTS, there are several underlying diseases and conditions that are known to cause or be associated with POTS or POTS like symptoms in some patients. This is a partial list:
-Autoimmune Diseases such as Autoimmune Autonomic Ganglionopathy, Sjogren’s Syndrome, Lupus, Sarcoidosis, Antiphospholipid Syndrome;1,3, 22
-Delta Storage Pool Deficiency13
-Diabetes and pre-diabetes
-Ehlers Danlos Syndrome – a collagen protein disorder than can lead to joint hypermobility and “stretchy” veins;3,12
-Infections such as Mononucleosis, Epstein Barr Virus, Lyme Disease, extra-pulmonary Mycoplasma pneumonia and Hepatitis C;1,2,3,4,10,11
-Mast Cell Activation Disorders;3
-Paraneoplastic Syndrome – rare small tumors of the lung, ovary, breast and pancreas that produce antibodies;1
-Toxicity from alcoholism, chemotherapy and heavy metal poisoning.1
-Traumas, pregnancy or surgery;1,2,3
Each patient is different, thus consulting with a physician who has experience in treating autonomic disorders is important. The most common treatments for POTS include increasing fluid intake to 2-3 liters per day; increasing salt consumption to 3,000 mg to 10,000 mg per day; wearing compression stockings; raising the head of the bed (to conserve blood volume); reclined exercises such as rowing, recumbent bicycling and swimming; a healthy diet; avoiding substances and situations that worsen orthostatic symptoms; and finally, the addition of medications meant to improve symptoms.1,3 Many different medications are used to treat POTS, such as Fludrocortisone, Beta Blockers, Midodrine, Clonidine, Pyridostigmine, Benzodiazepines, SSRIs, SNRIs, Erythropoietin and Octreotide.1,3 If an underlying cause of the POTS symptoms can be identified, treating the underlying cause is very important as well.
Currently, there is no cure for POTS, however researchers believe that some patients will see an improvement in symptoms over time. Detailed long term follow up studies on the course of POTS are sparse, but Dysautonomia International is working with researchers to begin to collect long term follow up data. With proper lifestyle adjustments, exercise, diet and medical treatments, many patients see an improvement in their quality of life.1 If an underlying cause can be identified, and if that cause is treatable, the POTS symptoms may subside. While the prognosis is good for most patients, researchers have noted that some patients will not improve and may actually worsen over time.1
The longest follow-up study done to date comes from Mayo Clinic.20 Mayo Clinic did a survey of their pediatric POTS patients seen between 2003 and 2010. Of those who responded to the survey, 18.2% reported a complete resolution of their POTS symptoms, while 52.8% reported persistent but improved symptoms. Male patients were twice as likely to report recovery. The average survey respondent had been diagnosed for about 5 years. Both patients who fully recovered and those who did not had mental health scores similar to the national norm.
Is a relatively recent (within last 20 years) syndrome, meaning it is a group of symptoms lumped together and has no clear blood work that can label it a disease as of yet.
Similar to migraine, there is no clinical or laboratory confirmation for VM.
1. Vestibular migraine
A. At least 5 episodes with vestibular symptoms
moderate or severe intensity
2. lasting 5 min to
B. Current or previous history of migraine with or without
aura according to the International Classification
of Headache Disorders (ICHD)
C. One or more migraine features with at least 50% of
the vestibular episodes
– headache with at least two of the following characteristics:
one sided location, pulsating quality,
moderate or severe pain intensity, aggravation by
routine physical activity
– photophobia and phonophobia
– visual aura
D. Not better accounted for by another vestibular or
2. Probable vestibular migraine
A. At least 5 episodes with vestibular symptoms of
moderate or severe intensity, lasting 5 min to
B. Only one of the criteria B and C for vestibular migraine
is fulfilled (migraine history or migraine features
during the episode)
C. Not better accounted for by another vestibular or
No one has done a high-quality treatment trial as of yet. Thus for VM or Migraine Associated with Vertigo, the goal for now is to treat the underlying migraine.