What is PoTS?
- Postural- position of the body
- Tachycardia- fast heart rate
- Syndrome- a combination of symptoms
Postural tachycardia syndrome is an abnormality of the functioning of the autonomic (involuntary) nervous system
Definition and diagnostic criteria:
- Patient must experience PoTS symptoms mostly when upright over a period of at least 3 months.
- 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.
- Many symptoms are experienced in the upright position (usually standing) and relieved by lying down.
Patients can be very disabled by their symptoms. Fortunately, for many patients, symptoms will improve with lifestyle changes, although some people will require medication. However, some will have symptoms over many years.
The Autonomic Nervous System
Postural Tachycardia Syndrome (PoTS) is an abnormality of the autonomic nervous system (ANS). A malfunctioning ANS is sometimes called ‘dysautonomia’. The autonomic nervous system 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 narrow, and heart rate increases slightly to maintain blood supply to heart and brain.
What happens when I have PoTS and stand up?
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 of PoTS
Orthostatic Symptoms – occur when upright
- Palpitations
- Palpitations are a sensation of your heart pounding in your chest.
- 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 30-60% of people with PoTS experience fainting. Some people think that all patients with PoTS faint, but this is not correct.
- Chest pain
- Chest pain is fairly common in patients and can be worse when upright. The cause is not clear.
- Shortness of breath
- Patients can feel breathless when standing up or with slight exertion.
-
- Shakiness or Tremulousness
- Excessive sweating
Non-orthostatic symptoms
- Gut problems
- Symptoms may include nausea, diarrhoea, constipation, bloating, abdominal pain and vomiting. Many people with PoTS are told that they have irritable bowel syndrome.
- Bladder problems
- Problems with circulation
- Visual problems
- This can be described as excessive glare, blurred or tunnel vision.
- “PoTS feet” (peripheral acrocyanosis)
- Purple hands and feet affect around half of patients.
Other: tiredness, brain fog, headaches, excercise intoletance, poor sleep,
Causes/Subtypes
Neuropathic PoTS
The nerves that serve the autonomic nervous system in the hands and feet do not work properly, resulting in widening of the blood vessels and tachycardia. 50% of people may experience pooling of blood in the stomach, pelvis, hands and feet (PoTS feet/blood pooling/acrocyanosis).
There may also be loss of sweating in the lower limbs.
Deconditioning is common.
Blood tests to check for autoimmunity may be abnormal in neuropathic PoTS.
Hypovolaemic POTS (reduced blood volume/dehydration)
30% of patients have low levels of sodium expelled in the urine (<170 mmol per 24 hours), which may indicate a low blood volume.
Hypovolaemia may occur as a result of gut problems such as diarrhoea, feeling sick and vomiting.
Hyperadrenergic PoTS
Between 30-60% of patients may have high levels of blood norepinephrine levels on standing and a high or fluctuating blood pressure.
When upright, individuals may experience palpitations, a sense of anxiety, tremor, and cold sweaty hands and feet. Also, in a good proportion of individuals, there is a significant urge to pass urine after even a short period of time upright.
Symptoms may worsen with physical and emotional stress.
Hyperadrenergic PoTS can occur as a result of both hypovolaemia and neuropathic PoTS.
Norepinephrine Transporter (NET) Deficiency is suggested as a mechanism for hyperadrenergic type PoTS. There may be an abnormality in a gene that leads to too much norepinephrine circulating in the body.
Deconditioning
Deconditioning (being out of shape) is present in many 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.
66% of those in a survey of UK PoTS patients were physically active at the time of onset of PoTS and it is unclear to what degree deconditioning is cause or effect.
Diagnosing PoTS
Detailed questioning of the patient is the key to accurate diagnosis. Physical examination and appropriate investigations are also important.
Alternative causes of symptoms need to be considered and identified.
Patients are often diagnosed by a cardiologist, neurologist or medicine for the elderly consultant or paediatrician, but other healthcare professionals can also diagnose PoTS.
To be given a diagnosis of PoTS, a person needs to have:
- PoTS symptoms mostly when upright over a period of at least 3 months.
- 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
Electrocardiography (ECG), The Active Stand Test, Head-Up Tilt Table Test, 24-hour ambulatory blood pressure and heart rate monitor, Echocardiogram (heart ultrasound), 24-hour urine collection
Managing PoTS
Postural Tachycardia Syndrome (PoTS) 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!
Management for PoTS falls into two different categories:
- Non-pharmacological (without medicines)
- Pharmacological (using medicines)
Factors which may make PoTS symptoms worse:
- Time of day – symptoms tend to be worse in the morning, particularly after getting out of bed after waking up.
- Rapidly moving from lying or/ sitting to a standing position.
- Dehydration
- Environmental heat
- Alcohol which causes the blood vessels to widen, therefore lowering blood pressure.
- Exercise or physical exertion. (It is important to note that whilst occasional exertion can exacerbate symptoms, an ongoing exercise program can improve symptoms, and is often recommended by specialists.)
- Menstrual periods
- Prolonged bed rest or deconditioning (becoming unfit)
- Prolonged standing (or sitting)
- Stimulants such as tea, coffee, alcohol and nicotine.
- Large heavy meals high in refined carbohydrates such as sugar and white flour.
Daily management of symptoms
- 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 and; ensure that they are achievable.
- Planning – if there is something more challenging you need to do on a particular day, plan your activity, 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 physical and psychological stressors.
- Infections and other illnesses can worsen symptoms – rest and accept a reduction in activity levels if you become unwell. You may take longer than expected to recover.
- Exercise – try to do something each day, even for just a few minutes.
- Mobility aids – although keeping as mobile as possible is important, for those with severe symptoms, the use of a wheelchair or mobility scooter may be helpful to manage daily living.
- Eat and drink regularly – symptoms are often exacerbated on busy days when routine eating and drinking patterns change; make sure you keep to your routine with diet and fluids.
Source- Home - PoTS UK