Postural Orthostatic Tachycardia Syndrome (POTS) is a complex and often misunderstood condition affecting millions. Understanding its diverse causes and triggers is important for accurate diagnosis and effective management.
What is POTS?
Postural Orthostatic Tachycardia Syndrome, or POTS, is a disorder of the autonomic nervous system, the body’s automatic control system. This system regulates involuntary functions such as heart rate, blood pressure, digestion, and body temperature. In individuals with POTS, the body struggles to coordinate the necessary responses when transitioning from lying down to an upright position.
When a person with POTS stands up, there is an abnormal and exaggerated increase in heart rate, typically at least 30 beats per minute (bpm) in adults within 10 minutes, or 40 bpm in adolescents. This rapid increase in heart rate happens without a significant drop in blood pressure, which differentiates it from other orthostatic conditions. The symptoms often include dizziness, lightheadedness, fatigue, and difficulty concentrating, commonly referred to as “brain fog.”
Preceding Conditions and Events
Acute events or conditions often precede POTS onset, suggesting they act as triggers. These can disrupt the body’s regulatory systems, leading to dysautonomia.
Viral infections
Viral infections are a common precursor to POTS. Viruses such as Epstein-Barr, influenza, and Lyme disease have been implicated. The COVID-19 virus has also shown a significant link to new-onset POTS, with some “long-haulers” developing the syndrome months after infection. This is often described as a post-viral syndrome, where the immune response may lead to lasting autonomic dysfunction.
Physical trauma
Physical trauma, including concussions and other head injuries, can contribute to POTS development. Traumatic brain injuries can disrupt autonomic nervous system function, increasing POTS-like symptoms. Damage to brain areas regulating heart rate and blood pressure can lead to dysregulation.
Surgery
Surgery can sometimes precede POTS onset. The stress from a major surgical procedure and anesthesia may act as a trigger in susceptible individuals. This physiological stress can perturb the autonomic nervous system’s delicate balance, leading to dysfunction.
Pregnancy
Pregnancy can initiate or worsen POTS symptoms, particularly during or after delivery. Hormonal fluctuations, increased blood volume, and physical demands can alter autonomic nervous system function. While some pregnant individuals with POTS improve due to increased blood volume, others face increased challenges, especially in later trimesters.
Autoimmune Connections
The immune system’s role in POTS is an active research area, with growing evidence suggesting autoimmune mechanisms. An autoimmune condition occurs when the body’s immune system mistakenly attacks its own healthy tissues, leading to inflammation and damage.
Certain autoimmune diseases frequently co-occur with POTS or may contribute to its development. These include Sjogren’s syndrome, celiac disease, lupus, Hashimoto’s thyroiditis, and rheumatoid arthritis. Studies indicate a notable percentage of POTS patients also have a diagnosed autoimmune condition; for instance, one study found 20% had a coexisting condition.
Researchers have identified autoantibodies in individuals with POTS, suggesting the immune system may target autonomic nervous system components. These autoantibodies might interfere with receptors regulating blood vessel constriction and heart rate. While their presence suggests an autoimmune link, their precise clinical significance and direct role in causing POTS symptoms are still being investigated.
Genetic Predispositions
Inherited factors and specific genetic conditions can increase POTS risk. The familial component is evident, as it often appears in multiple family members, suggesting a genetic predisposition. While no single gene is the sole cause for most POTS cases, research explores these hereditary links.
Ehlers-Danlos Syndrome (EDS)
Ehlers-Danlos Syndrome (EDS), an inherited connective tissue disorder, is a recognized genetic condition linked to POTS. Fragile connective tissue in EDS can lead to joint hypermobility and blood vessel issues, contributing to blood pooling and orthostatic intolerance. Approximately 80% of individuals with hypermobile EDS (hEDS) also experience POTS, highlighting a substantial overlap.
Mast Cell Activation Syndrome (MCAS)
Mast Cell Activation Syndrome (MCAS) is frequently associated with POTS. Mast cells are immune cells that release inflammatory mediators, and in MCAS, they become overactive. This dysregulation can lead to symptoms overlapping with POTS, such as rapid heart rate, dizziness, and fatigue. The frequent co-occurrence of EDS, MCAS, and POTS suggests a complex interplay of genetic and physiological factors.
Beyond these syndromes, research points to genetic variations in genes regulating neurotransmitters and autonomic function. For example, some studies explore mutations in the norepinephrine transporter (NET) gene, which regulates norepinephrine levels, a neurotransmitter important for heart rate and blood pressure control. While these genetic factors contribute to susceptibility, they often interact with environmental triggers.
Idiopathic POTS
Despite extensive research, a significant portion of POTS cases remain without a clear, identifiable cause. This is “idiopathic POTS,” meaning the origin is unknown. Even without a pinpointed trigger, symptoms are real and diagnosable.
The absence of a known cause does not diminish the condition’s validity or impact. POTS is a recognized medical diagnosis, and effective management strategies are available. Research continues to investigate idiopathic cases, aiming to uncover new insights.