Introduction

What is postural orthostatic tachycardia syndrome?

Breaking down the terminology for better understanding:

• Postural: Concerning the body's posture
• Standing erect is known as orthostatic
• Tachycardia is an elevated heart rate
• A syndrome is a collection of conditions or signs.

Postural tachycardia syndrome (POTS) occurs when your heart rate rapidly rises after you get up from a sitting or lying position.¹ A quick heartbeat, lightheadedness, and exhaustion are some symptoms of this blood circulation condition.^2,3 Currently, there is no cure, but symptoms can be managed with lifestyle changes.¹ 

What is the cause of this condition?

Normally, your body’s autonomic nervous system balances your heart rate and blood pressure to keep your blood flowing at a healthy pace, no matter what position your body is in. If you have POTS, your body can’t coordinate the balancing act of blood vessel constriction (squeezing) and heart rate response. This means that your body can’t keep your blood pressure steady and stable. This causes a variety of symptoms. Every case of POTS is different, so each person may experience different symptoms.³ 

How to check if you have POTS?

Understanding the symptoms of POTS helps diagnose it. Only after orthostatic hypotension has been ruled out and no severe dehydration or blood loss has occurred is POTS diagnosed. 

A 20 mm Hg reduction in systolic blood pressure or a 10 mm Hg dip in diastolic blood pressure during the first three minutes after standing up straight is known as orthostatic hypotension. An increase in heart rate of at least 30 beats per minute in adults or at least 40 beats per minute in teenagers during the first ten minutes of standing up from a horizontal position (or as measured on a tilt table).²

Whom does it affect?

Although the exact causes of POTS are unknown, women are more likely than men to have it, and teenagers and young people are more prone to develop it.² 

Individuals are more likely to develop POTS when:

• Serious infections or viral diseases like mononucleosis are examples of significant illnesses
• Pregnancy
• Bodily harm, such as a brain injury
• Surgery.

POTS is also more common in those with certain autoimmune diseases, including Sjogren's syndrome, lupus, and celiac disease.³ 

Types of POTS

The types of POTS are related to its causes:

• Neuropathic POTS: It is associated with injury to tiny fibre neurons that control blood vessel constriction
• Hyperadrenergic POTS: It is characterised by increased levels of the stress hormone norepinephrine 
• Hypovolemic POTS: It is linked to decreased blood volume
• Secondary POTS: It frequently coexists with autoimmune diseases and diabetes, two major illnesses that can result in autonomic neuropathy

This article mainly discusses the neurological symptoms of POTS. About 50% of the patients deal with neuropathic POTS, which underscores the importance of understanding it.⁴ 

Overview of Neurological Involvement in POTS

The term neuropathic POTS describes a subgroup of patients with indirect evidence of peripheral sympathetic denervation in the lower limbs. This condition is characterised by loss of sweating in the feet on thermoregulatory sweat tests and impaired increase of norepinephrine (NE) release in the lower limb in response to orthostatic stress. In a large series, 54% of patients demonstrated indications of peripheral sudomotor denervation. It is assumed that inadequate peripheral vasoconstriction, which results in venous pooling in the lower limbs, is the main pathophysiologic explanation of postural intolerance in this subgroup of patients.⁵ 

Autonomic nervous system disorder and POTS

POTS is caused by an inability to coordinate the autonomic nervous system's (ANS) regulation of heart rate with the blood flow to adjust for a shift in body posture. When standing up or pulling the body into an upright position, gravity will tend to cause blood to flow in the direction of the lower body, leaving the brain and upper body without as much blood flow. The ANS directs the blood vessels in the lower half of the body to constrict, forcing blood up toward the brain, counteracting the effects of gravity, and ensuring that the brain is properly supplied. When the ANS is unable to accomplish this, a set of symptoms known as POTS develops.⁶ 

Neurological symptoms of POTS

According to a 2017 study by Stiles et al., individuals with neurological POTS describe numbness, tingling, and burning in their hands, feet, and face. Additional autonomic symptoms included headache, dizziness, headache, headache, constipation, diarrhoea, headache, double vision, and difficulties peeing. Additionally, patients also experienced choking or swallowing issues, dry eyes, and dry lips. 

Even though POTS patients have a wide spectrum of neurological symptoms, most of them are referred to cardiologists or cardiac electrophysiologists (perhaps because of their noticeable tachycardia). Neurologists who are more adept at diagnosing POTS may also be able to treat its neurological symptoms more effectively.⁷

Headaches in POTS

In POTS populations, migraines and other primary headaches are very common. Autonomic dysfunction might also present as orthostatic headache (related to posture). The headache starts or gets worse within fifteen minutes of standing or sitting. This lag time could last for several hours in certain patients. After lying down, the headache goes away or becomes better in 15 to 30 minutes.⁸

Because of blood pooling, decreased cerebral perfusion, and muscle strain from prolonged upright posture, POTS patients may have a variety of headache forms, including tension-type, pressure-like, and cervicogenic headaches.

When a POTS patient experiences headaches, two particular factors need to be taken into account: 

• First, the headache mechanisms or types that are more common in people with POTS. The kind, severity, and frequency of these headaches might all differ, which may be connected to the variations in blood pressure and flow that define POTS and could be brought on by adjustments in posture or activity 
• Second, the effectiveness of particular treatments may be impacted by symptoms and comorbidities that are typical of POTS patients⁹ 

In addition to using drugs and physical therapy to reduce symptoms, management techniques include lifestyle modifications, including wearing compression garments and drinking more water.

Migraines in POTS

About 41% to 96% of persons with POTS also suffer from migraines, which are worse when standing and better when sitting, according to studies. One side of the head is frequently affected by migraines, which can cause agonising pulsating or throbbing pain. 

Neuropeptides are released close to sensory fibres that innervate the meninges and meningeal arteries during migraine attacks. These peptides cause vasodilation as well as pain.¹⁰ Usually, both preventative and abortive measures are used in treatment. While preventative drugs try to lower the frequency of attacks, abortive therapies are used to treat acute migraine attacks. Interestingly, beta-blockers, even at lesser dosages, have been demonstrated to be effective in preventing migraines when treating POTS. Tailored treatment regimens are crucial for providing the best possible management of both disorders by keeping an eye out for possible interactions between migraine drugs and POTS symptoms.¹¹

Anxiety and Mental Health in POTS

POTS patients also experience cognitive dysfunction symptoms, such as mental exhaustion or fogginess. With their minds going blank and them having trouble concentrating, thinking, and finding the correct words, these symptoms may make it difficult to go about their everyday lives. The fact that these symptoms can manifest both while sitting and even when lying down suggests that posture has nothing to do with them. POTS victims experience anxiety and depression as well, though research on this topic is scarce.¹²

Palpitations, dizziness, nausea, and chest pain are some of the prevalent symptoms of orthostatic intolerance that are also indicators of anxiety disorders.¹³ Rather than being solely psychological, these anxiety symptoms could also result from the physiological repercussions of the condition. To treat anxiety and POTS symptoms, treatment usually consists of pharmaceutical therapies, cognitive-behavioural therapy (CBT), and lifestyle modifications. Improving patient outcomes requires a thorough strategy.¹⁴

Coping Strategies and Patient Support 

A multidisciplinary approach involving neurologists, cardiologists, and psychologists is crucial for managing symptoms effectively.¹⁵ Patient education and advocacy, alongside significant lifestyle adjustments and careful activity pacing, empower individuals to navigate daily challenges. Online communities and patient-led awareness initiatives play a vital role in fostering support and shared understanding among those affected.¹⁶ This comprehensive strategy promotes both physical and mental well-being in patients.¹⁷

FAQs

Why do symptoms of POTS vary for each individual?

There are several reasons why people with POTS have different symptoms. When standing, ineffective blood vessel reactions cause blood to pool in the lower body, which lowers blood supply to the brain and results in symptoms like weariness and dizziness. Chest pain and shakiness may be the result of the autonomic nervous system compensating by releasing hormones that raise the heart rate. Additionally, the wide range of symptoms that each person with POTS experiences is influenced by individual variations in physiology and blood pressure responses.¹ 

Is anxiety in POTS caused by psychological issues or the condition itself?

In POTS, anxiety is frequently caused by aberrant autonomic responses in the body rather than only psychological aspects. This physiological response is frequently confused with fundamental anxiety disorders.¹⁴ 

Summary

Anxiety, migraines, and headaches frequently produce a vicious cycle in which anxiety sets off migraine attacks, which in turn heighten anxiety levels and increase headache frequency and severity. The significance of holistic management approaches that concurrently address the psychological and physiological components of these illnesses is highlighted by this interaction. A mix of behavioural therapy and pharmaceutical modifications may be used in an effective treatment program, which can greatly enhance the quality of life for individuals impacted.¹⁵