What is PoTS?

Postural tachycardia syndrome is an abnormality of the functioning of the autonomic (involuntary) nervous system. To be diagnosed with PoTS, an individual must experience a group of symptoms in the upright position (usually standing) that are relieved by lying down. A persistent increase in heart rate of 30 beats per minute (40 bpm if under 19 years of age) should be recorded within ten minutes of standing. Blood pressure (BP) does not always drop in PoTS.

Fortunately, for many patients, symptoms will improve with a combination of life style changes and medication. 

The Autonomic Nervous System

The Postural Tachycardia Syndrome (PoTS) is an abnormality of the autonomic nervous system. The autonomic nervous system (ANS) is in charge of all bodily functions that we don’t have to think about, such as:

• Heart rate and blood pressure regulation
• Digestion
• Bladder control
• Sweating
• Stress response

The sympathetic nervous system is part of the autonomic nervous system. It produces the ‘fight or flight’ or ‘stress’ response. When activated, a chemical called norepinephrine is released. Amongst other things, this causes an increase in heart rate and blood pressure.

What should happen to my blood when I stand up?

When a healthy person stands up, blood vessels contract and heart rate increases slightly to maintain blood supply to heart and brain.

What happens when I have PoTS and stand up?

you know you have pots when

• In PoTS, this automatic adjustment to upright posture is not working correctly, resulting in an excessive rise in heart rate, increased norepinephrine in the blood and altered blood flow to the brain.

Symptoms

Orthostatic intolerance: is a term that is sometimes used to describe symptoms of PoTS. It means symptoms that occur on standing and are relieved by lying down. In addition to heart rate and blood pressure, other bodily functions that are regulated by the autonomic nervous system can be affected.

Symptoms can be debilitating, ranging from mild to severe and varying from day to day.

• Dizziness or light-headedness or presyncope (almost fainting): These symptoms usually occur when standing up,  but can occur with prolonged sitting.
• Syncope (fainting or blackouts): Approximately 30% of people with PoTS experience fainting.
• Palpitations: Palpitations are a sensation of your heart pounding in your chest.
• Headaches: Approximately two thirds of those with PoTS have orthostatic headaches which means they occur as a result of being upright and may be caused by reduced blood supply to the brain.  Most people with PoTS also have migraine type headaches.
• Tiredness or weakness: These are common symptoms of PoTS and can last for a considerable time after a bout of symptoms of PoTS.
• Brain fog: People with PoTS often complain of ‘brain fog’ which is difficulty in thinking or concentrating.
• Shakiness or Tremulousness: This is often worse with upright posture.
• Shortness of breath: Patients can feel breathless when standing up or with slight exertion.
• Chest pain: Chest pain is fairly common in patients and can be worse when upright. The cause is not clear.
• Excessive or patchy reduced sweating.
• Gut problems.
• Nausea is common. Other symptoms include diarrhoea, constipation, bloating, abdominal pain and vomiting.  Many people with PoTS are told that they have irritable bowel syndrome.
• Poor sleep: Many patients with PoTS have insomnia. This can be trouble getting to sleep, waking in the middle of the night and trouble getting back to sleep.
• Visual problems: This can be described as excessive glare, blurred or tunnel vision.
• Bladder problems.

Triggers which may worsen symptoms

• Excess heat
• After eating – especially refined carbohydrate eg sugar, white flour
• Speed of positional change – don’t stand up quickly
• Dehydration
• Time of day (may be worse in the morning, especially rising after wakening)
• Menstrual period
• Deconditioning or prolonged bed rest
• Alcohol which dilates blood vessels
• Exercise (occasional exercise can cause one to feel worse, but an ongoing exercise program can improve symptoms)

How is PoTS Diagnosed?

Patients are usually diagnosed by a cardiologist or neurologist.

To be given a diagnosis of PoTS, a person needs to have:

• A sustained increase in heart rate of greater than 30 beats per minute within 10 minutes of standing
• Those aged 12-19 years require an increase of at least 40 beats per minute
• These criteria may not apply to those with a low heart rate when resting
• There is usually no drop in blood pressure on standing

Investigations: It may be necessary for patients to have some or all of the tests below:

Electrocardiography (ECG): An ECG is performed to rule out any heart problems that may cause symptoms similar to those found in PoTS.

The Active Stand Test: The active stand test can be used to diagnose PoTS. Under careful supervision, heart rate and blood pressure are measured after resting lying down, then immediately upon standing and after 2, 5 and 10 minutes. This test may bring on symptoms of PoTS and some people may faint.

Head-Up Tilt Table Test: This involves lying on a table that can be tilted to an angle of 60 to 70 degrees in a quiet, dimly lit, temperature controlled room. Blood pressure and heart rate are recorded in a continuous manner. After a period of 5 to 20 minutes of lying flat, the table is tilted. Although a diagnosis of PoTS should be made by an increase in heart rate of 30 bpm within the first 10 minutes, this upright position can last between 10 and 45 minutes. The patient will be asked how they are feeling during the test, so symptoms can be matched with heart rate and blood pressure.  The test will end if your blood pressure becomes too low, satisfactory results have been obtained, or the maximum time has elapsed.

24 hour ambulatory blood pressure and heart rate monitor: Sticky patches are applied to the chest and are linked to a little box which is attached by a belt your waist. It monitors heart rate over a 24 hour period. A blood pressure cuff on your arm will intermittently check your blood pressure. The patient is asked to go about their usual daily activities, trying to reproduce events that seem to cause the symptoms.  A diary stating the time and activity performed at the moment when the symptoms started should be kept. Doctors look to see if there is a fast heart rate or drop in blood pressure at the time of symptoms.

Echocardiogram (Heart Ultrasound): This test is to check if the heart’s structure is normal. In this test a technician will apply some jelly on the chest and will roll an ultrasound probe in many directions to create a 3 dimensional image of the heart. It is a painless and harmless test that similar to the ultrasound scan used routinely during pregnancy to look at the unborn baby.

24-hour Urine Collection : Individuals with PoTS often have low urinary sodium levels of less than 150 millimole per 24 hours.

Blood tests: Bloods are taken to rule out other conditions.  These may include:

• Kidney function
• Blood count including ferritin
• Liver tests
• Thyroid tests
• Calcium levels
• Glucose

Other tests which may be carried out

• EEG
• Autonomic function screening tests
• Sweat testing

Types of PoTS

• There are a number of factors and disorders causing or associated with the condition but in some cases, a cause is never identified.
• PoTS has been reported to commence after an infection such as a viral illness, an acute stressor such as pregnancy or surgery, a traumatic event or immunisation.

PoTS in Teenagers

It usually starts between the ages of 12-14 years old and may follow a very rapid growth spurt, with worsening symptoms until the age of 16.

Deconditioning

Deconditioning (being out of shape) is present in some individuals with PoTS. A traumatic event or illness can result in reduced activity or bedrest. Patients become unfit and the heart doesn’t pump as efficiently as before. This can trigger symptoms of orthostatic intolerance so patients avoid exercise which makes their symptoms worse, leading to more physical inactivity. There is a downward spiral of deconditioning which causes or worsens symptoms of PoTS.

Hyperadrenergic PoTS

Hyperadrenergic type PoTS is less common. This can appear similar to pheochromocytoma (a norepinephrine producing tumour) and tests may be needed to rule this out.

When upright, individuals may experience a sense of anxiety, tremor, and cold sweaty hands and feet. Also, in a good portion of individuals, there is a significant urge to pass urine after even a short period of time upright. True migraine headaches are also common.

Blood norepinephrine levels are often high. Blood pressure may also increase (not fall) on standing up.

Norepinephrine Transporter (NET) Deficiency and Blockers

This type of PoTS is similar to Hyperadrenergic PoTS.  There may be an abnormality in a gene that leads to too much norepinephrine circulating in the body. There are many antidepressant and antianxiety drugs (SNRIs) that work, in part, by blocking this transporter.  These can increase heart rate and make symptoms worse in some patients.

Other Conditions associated with PoTS

• Joint Hypermobility Syndrome
• Joint hypermobility syndrome (JHS) which is also called benign joint hypermobility syndrome, Ehlers-Danlos (hypermobility type) or Ehlers-Danlos type III is often associated with PoTS.

Hypermobile joints are common, especially in children. This can be a harmless finding and can even be an advantage in sport. If you can answer yes to two of the following questions it is likely that you have hypermobile joints.

• Can you now (or could you ever) place your hands flat on the floor without bending your knees?
• Can you now (or could you ever) bend your thumb to touch your forearm?
• As a child did you amuse your friends by contorting your body into strange shapes OR could you do the splits?
• As a child or teenager did your shoulder or kneecap dislocate on more than one occasion?
• Do you consider yourself double-jointed?                                                                                   

Joint hypermobility SYNDROME is NOT the same as joint hypermobility and patients with the syndrome will have some of the following additional features:

• Painful hypermobile joints that may dislocate
• Back pain. Frequent strains and sprains
• Co-ordination problems – clumsiness, delayed walking and writing
• Resistance to local anaesthetics
• Skin changes – soft, velvety, thin, stretchy, poor healing, thin papery scars, stretch marks, drooping lids
• Blue tinge to the whites of the eyes
• Tall and slim with long arms and fingers
• Stress incontinence at a younger age. Rectal prolapse
• Gut problems
• Autonomic nervous system problems - PoTS and low blood pressure

Joint hypermobility syndrome is one of the more common conditions associated with PoTS. It is an inherited condition that can be passed down in families. The underlying problem is thought to be faulty connective tissue protein that is found throughout the body including blood vessels, joints and gut and may lead to stretchy or brittle tissues. Patients who have the combination of JHS and PoTS tend to develop symptoms of PoTS at an earlier age, faint more often and suffer from migraine.

• Low Blood pressure: Low blood pressure can be healthy, but if it drops very low on standing it is called orthostatic hypotension and can cause symptoms similar to PoTS. Reflex syncope occurs when a drop in blood pressure results in fainting.
• PoTS, low blood pressure and reflex syncope can exist together in the same patient and this combination can be seen in joint hypermobility syndrome and chronic fatigue syndrome.
• When blood pressure drops there is sometimes an increase in heart rate. This is called a reactive tachycardia and can look like PoTS.

Treatments for both conditions are similar.

Chronic Fatigue Syndrome (CFS)

• PoTS may be under diagnosed in those with chronic fatigue syndrome (CFS) and is estimated to affect around 25-50% of people with CFS. It has been suggested that these two conditions may be part of the same group of conditions with similar causes.

Inappropriate Sinus Tachycardia (IST)

• Inappropriate sinus tachycardia (IST) is another condition which has similar symptoms to hyperadrenergic PoTS. Patients with IST have a high heart rate when lying down (around 90-100bpm) which rapidly accelerates with slight exertion or emotional stress. The two conditions can overlap and may share the same underlying causes. Treatment options are similar and need to be tailored to the individual.

Mast Cell Activation Disorder

• This needs to be considered if flushing or allergies are prominent.

Autoimmune conditions

• Recent research has shown that auto-antibodies affecting the autonomic nervous system are more common in people with PoTS.
• Autoimmune conditions that have been associated with PoTS include Sjogrens syndrome and antiphospholipid  (Hughes) syndrome. Treatment of underlying conditions can improve symptoms of PoTS.

Other

• PoTS may develop as a consequence of a number of other medical conditions such as diabetes, cancer, multiple sclerosis, Lyme disease.

POTS Treatment

There's no cure for POTS, but treatment can help with your symptoms.

• Medication. Your doctor may prescribe drugs such as fludrocortisone (along with more salt and water), midodrine, phenylephrine, or a type of medicine called a beta-blocker to help with blood flow.
• Compression stockings. These help push the blood up from your legs to your heart. You’ll want ones that provide at least 30 to 40 minutes of compression and go all the way up to your waist, or at least up to your thighs. Your doctor can prescribe a pair.
• Diet. Salt and water are key. They keep fluids in your body and raise the amount of blood in your body. Think pickles, olives, nuts, and salted broths. Eat smaller meals more often with a healthy balance of protein, vegetables, fruits, and dairy.
• Exercise. POTS can make it hard to be active, but even light exercise such as walking or simple yoga can help with blood flow and keep your heart healthy.
• Lifestyle. If you get tired easily, you may not always have the energy to take care of yourself. Learn how to take your pulse and blood pressure. Ask your doctor what your numbers should be, and check them regularly.
• Sleep. Try to stick to a sleep schedule. You also might raise the head of your bed to make it easier to stand up after lying down.
• Communication. POTS can make simple activities a bit harder, and that can be frustrating and stressful. A support group or therapist may help you manage the emotional issues the condition can cause.

General Advice

Postural tachycardia syndrome can be very debilitating. Fortunately, there are many adjustments to lifestyle that can lead to an improvement in symptoms. It's hard work, but can make a real difference.

Treatment for PoTS falls into two different categories: Non-pharmacological (without medicines) and pharmacological (using medicines), with non-pharmacological therapies being the cornerstone of any PoTS treatments. In milder cases of PoTS, those therapies might be sufficient to control symptoms, and might be all that is needed.

PoTS has an impact on every aspect of life which include the physical, social and psychological. Symptoms tend to fluctuate from day to day making management a challenge. Medication can improve symptoms, but there are many non-pharmacological (without medication) methods which may help.

Factors which may have an impact on symptoms

• Time of day – symptoms tend to be worse in the morning
• Rapidly moving for a lying/sitting to standing position
• Dehydration
• Food ingestion
• Extreme heat
• Alcohol
• Physical exertion
• Menstrual period
• Prolonged bed rest or deconditioning (becoming unfit)
• Prolonged standing (or sitting)

Daily management of symptoms balance your life

• Pace yourself throughout the day. Try not to fit too much in – there will always be another day.  Take your time and avoid rushing.
• Goals: be realistic; ensure that they are achievable.
• Planning: if there is something specific you need to do on a day, plan for it, rest well beforehand and create time to recover afterwards.
• Limits: learn to know and live within your limits.
• Avoid stress: the autonomic nervous system is the body's fight/flight mechanism, and is activated during periods of stress. PoTS sufferers tend to be very sensitive to stressors, whether they are psychological or physical, positive or negative.
• Infections worsen symptoms: rest and accept a reduction in activity levels. You may take longer than expected to recover.
• Stairs are a challenge: try to limit the amount of times needed to run up and down stairs.  Walk up slowly and steadily. Take a lift where possible.
• Mobility aids: For those with the most severe symptoms, the use of a wheelchair or mobility scooter may be helpful to manage daily living.
• Elevating: the head of the bed has also been recommended.

References:

https://www.mayoclinic.org/medical-professionals/endocrinology/news/postural-orthostatic-tachycardia-syndrome-a

https://my.clevelandclinic.org/health/diseases/16560-postural-orthostatic-tachycardia-syndrome-pots

https://www.nhs.uk/conditions/postural-tachycardia-syndrome/

https://www.hopkinsmedicine.org/health/conditions-and-diseases/postural-orthostatic-tachycardia-syndrome-pots

https://en.wikipedia.org/wiki/Postural_orthostatic_tachycardia_syndrome

https://www.potsuk.org/mcas

https://www.potsuk.org/general_advice

https://www.webmd.com/heart-disease/atrial-fibrillation/postural-orthostatic-tachycardia

https://myheart.net/pots-syndrome/

https://kidshealth.org/en/parents/pots.html