The causes of POTS are varied.[14] It may develop after a viral infection, surgery, trauma, autoimmune disease, or pregnancy.[7] It has been shown to emerge in previously healthy patients after COVID-19,[15][16][17] or possibly in rare cases after COVID-19 vaccination, though causative evidence is limited and further study is needed.[18] POTS is more common among people who got infected with SARS-CoV-2 than among those who got vaccinated against COVID-19.[19] Risk factors include a family history of the condition.[1] POTS in adults is characterized by a heart rate increase of 30 beats per minute within ten minutes of standing up, accompanied by other symptoms.[1] This increased heart rate should occur in the absence of orthostatic hypotension (>20mm Hg drop in systolic blood pressure)[20] to be considered POTS, though some patients with POTS do not show any changes in blood pressure upon standing. A spinal fluid leak (called spontaneous intracranial hypotension) may have the same signs and symptoms as POTS and should be excluded.[21] Prolonged bedrest may lead to multiple symptoms, including blood volume loss and postural tachycardia.[22] Other conditions that can cause similar symptoms, such as dehydration, orthostatic hypotension, heart problems, adrenal insufficiency, epilepsy, and Parkinson's disease, must not be present.[6]
Treatment may include avoiding factors that bring on symptoms, increasing dietary salt and water, small and frequent meals,[23] avoidance of immobilization,[23] wearing compression stockings, and medication.[24][25][1][26] Medications used may include beta blockers,[27]pyridostigmine,[28]midodrine[29] and fludrocortisone.[1] More than 50% of patients whose condition was triggered by a viral infection get better within five years.[7] About 80% of patients have symptomatic improvement with treatment, while 25% are so disabled they are unable to work.[8][7] A retrospective study on patients with adolescent-onset has shown that five years after diagnosis, 19% of patients had full resolution of symptoms.[30]
It is estimated that 1–3 million people in the United States have POTS.[31] The average age for POTS onset is 20, and it occurs about five times more frequently in females than in males.[1]
Signs and symptoms
Person standing and measuring heart rate with a pulse oximeter which shows tachycardia of 108bpm
POTS is a complex and multifaceted clinical disorder, the etiology and management of which remain incompletely understood. This syndrome is typified by a diverse array of nonspecific symptoms, making it a challenging condition to describe.[32]
Individuals living with POTS experience a diminished quality of life compared to healthy individuals, due to disruptions in various domains such as standing, playing sports, symptom anxiety, and impacts on school, work, or spiritual (religious) domains—these disruptions affect their daily life and overall well-being.[33]
In adults, the primary manifestation is an increase in heart rate of more than 30 beats per minute within ten minutes of standing up.[1][34] The resulting heart rate is typically more than 120 beats per minute.[1] For people between ages 12 and 19, the minimum increase for a POTS diagnosis is 40 beats per minute.[35] POTS is often accompanied by common features of orthostatic intolerance—in which symptoms that develop while upright are relieved by reclining.[34] These orthostatic symptoms include palpitations, light-headedness, chest discomfort, shortness of breath,[34] nausea, weakness or "heaviness" in the lower legs, blurred vision, and cognitive difficulties.[1] Symptoms may be exacerbated with prolonged sitting, prolonged standing, alcohol, heat, exercise, or eating a large meal.[36]
POTS and dysautonomia often presents with narrowed pulse pressures. In some cases, patients experience a drop in pulse pressure to 0mm Hg upon standing, rendering them practically pulseless while upright. This condition leads to significant morbidity, as many affected individuals struggle to remain standing.[37]
Up to one-third of POTS patients experience fainting for many reasons, including but not limited to standing, physical exertion, or heat exposure.[1] POTS patients may also experience orthostatic headaches.[38] Some POTS patients may develop blood pooling in the extremities, characterized by a reddish-purple color of the legs and/or hands upon standing.[39][40][41][42] 48% of people with POTS report chronic fatigue and 32% report sleep disturbances.[43][44][33][45][46] Other POTS patients only exhibit the cardinal symptom of orthostatic tachycardia.[41] Additional signs and symptoms are varied, and may include excessive sweating, lack of sweating, heat intolerance, digestive issues such as nausea, indigestion, constipation or diarrhea, post-exertional malaise, coat-hanger pain, brain fog, and syncope or presyncope.[47]
Whereas POTS is primarily characterized by its profound impact on the autonomic and cardiovascular systems, it can lead to substantial functional impairment. This impairment, often manifesting as symptoms such as fatigue, cognitive dysfunction, and sleep disturbances, can significantly diminish the patient's quality of life.[33]
Brain fog
One of the most disabling and prevalent symptoms in POTS is "brain fog",[11] a term used by patients to describe the cognitive difficulties they experience. In one survey of 138 POTS patients, brain fog was defined as "forgetful" (91%), "difficulty thinking" (89%), and "difficulty focusing" (88%). Other common descriptions were "difficulty processing what others say" (80%), "confusion" (71%), "getting lost" (64%), and "thoughts moving too quickly" (40%).[12] The same survey described the most common triggers of brain fog to be fatigue (91%), lack of sleep (90%), prolonged standing (87%), and dehydration (86%).[12]
There may be a loss of neurovascular coupling and reduced functional hyperemia in response to cognitive challenge under orthostatic stress – perhaps related to a loss of autoregulatory buffering of beat-by-beat fluctuations in arterial blood flow.[54]
Co-morbidities
Conditions that are commonly reported with POTS include:[10][13]
The pathophysiology of POTS is not attributable to a single cause or unified hypothesis—it is the result of multiple interacting mechanisms, each contributing to the overall clinical presentation; the mechanisms may include autonomic dysfunction, hypovolemia, deconditioning, hyperadrenergic states, etc.[32]
The symptoms of POTS can be caused by several distinct pathophysiological mechanisms.[34] These mechanisms are poorly understood,[35] and can overlap, with many patients showing features of multiple POTS types.[34] Many people with POTS exhibit low blood volume (hypovolemia), which can decrease the rate of blood flow to the heart.[34] To compensate for low blood volume, the heart increases its cardiac output by beating faster (reflex tachycardia),[56] leading to the symptoms of presyncope.
In the 30% to 60% of cases classified as hyperadrenergic POTS, norepinephrine levels are elevated on standing,[1] often due to hypovolemia or partial autonomic neuropathy.[34] A smaller minority of people with POTS have (typically very high) standing norepinephrine levels that are elevated even in the absence of hypovolemia and autonomic neuropathy; this is classified as central hyperadrenergic POTS.[34][42] The high norepinephrine levels contribute to symptoms of tachycardia.[34] Another subtype, neuropathic POTS, is associated with denervation of sympathetic nerves in the lower limbs.[34] In this subtype, it is thought that impaired constriction of the blood vessels causes blood to pool in the veins of the lower limbs.[1] Heart rate increases to compensate for this blood pooling.[57]
In up to 50% of cases, there was an onset of symptoms following a viral illness.[58] It may also be linked to physical trauma, concussion, pregnancy, surgery or psychosocial stress.[59][23][41] It is believed that these events could act as a trigger for an autoimmune response that result in POTS.[60] It has been shown to emerge in previously healthy patients after COVID-19,[61][15][16] or after COVID-19 vaccination.[18] A 2023 review found that the chances of being diagnosed with POTS within 90 days after mRNA vaccination were 1.33 times higher compared to 90 days before vaccination, still, the results are inconclusive due to a small sample size; only 12 cases of newly diagnosed POTS after mRNA vaccination were reported, all these 12 patients having autoimmune antibodies. However, the risk of POTS-related diagnoses was 5.35 times higher after getting infected with SARS-CoV-2 compared to after mRNA vaccination.[62] Possible mechanisms for COVID-induced POTS are hypovolemia, autoimmunity/inflammation from antibody production against autonomic nerve fibers, and direct toxic effects of COVID-19, or secondary sympathetic nervous system stimulation.[61]
Physical deconditioning may be a major factor involved in POTS.[66][67] Strong parallels have been found between POTS and strong physical deconditioning or people who have undergone prolonged periods of bed rest.[66][67] Both POTS and deconditioning are marked by cardiac atrophy, reduced blood volume, and other physical changes.[66][67] There are also similarities between POTS and deconditioning in response to exercise.[66][67]
Elevations of autoantibodies targeting the α1-adrenergic receptor has been associated with symptoms severity in patients with POTS.[71]
More recently, autoantibodies against other targets have been identified in small cohorts of POTS patients.[73] Signs of innate immune system activation with elaboration of pro-inflammatory cytokines has also been reported in a cohort of POTS patients.[72] Studies suggest the involvement of adrenergic, cholinergic, and angiotensin II type I autoantibodies in the pathogenesis of orthostatic intolerance, so that these autoantibodies are thought to interfere with the normal functioning of the autonomic nervous system, leading to the symptoms observed in POTS; as such, there is growing interest in the use of immunomodulation therapy as a potential treatment strategy for POTS: immunomodulation therapy aims to regulate or normalize the immune response, thereby reducing the production of harmful autoantibodies.[74]
Secondary POTS
If POTS is caused by another condition, it may be classified as secondary POTS.[7] Chronic diabetes mellitus is one common cause.[7] POTS can also be secondary to gastrointestinal disorders that are associated with low fluid intake due to nausea or fluid loss through diarrhea, leading to hypovolemia.[1] Systemic lupus erythematosus and other autoimmune diseases have also been linked to POTS.[59]
There is a subset of patients who present with both POTS and mast cell activation syndrome (MCAS), and it is not yet clear whether MCAS is a secondary cause of POTS or simply comorbid, however, treating MCAS for these patients can significantly improve POTS symptoms.[24]
POTS can also co-occur in all types of Ehlers–Danlos syndrome (EDS),[41][75] a hereditary connective tissue disorder marked by loose hypermobile joints prone to subluxations and dislocations, skin that exhibits moderate or greater laxity, easy bruising, and many other symptoms. A trifecta of POTS, EDS, and mast cell activation syndrome (MCAS) is becoming increasingly more common, with a genetic marker common among all three conditions.[76][77][78][79] POTS is also often accompanied by vasovagal syncope, with a 25% overlap being reported.[80] There are some overlaps between POTS and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), with evidence of POTS in 10–20% of ME/CFS cases.[81][80] Fatigue and reduced exercise tolerance are prominent symptoms of both conditions, and dysautonomia may underlie both conditions.[80]
There have also been reports of patients experiencing co-occurring POTS, May-Thurner Syndrome, and EDS.[75]
There are case reports of people developing POTS and other forms of dysautonomiapost-COVID.[16][83][84][85] There is no good large-scale empirical evidence yet to prove a connection, so for now the evidence is preliminary.[86]
Diagnosis
Results of a tilt table test positive for POTS
POTS is a complex disorder with a multifactorial etiology, and the diagnostics of POTS is challenging.[32]
POTS is most commonly diagnosed by a cardiologist (41%), cardiac electrophysiologist (15%), or neurologist (19%).[2] The average number of physicians seen before receiving diagnosis is seven, and the average delay before diagnosis is 4.7 years.[2]
Diagnostic criteria
A POTS diagnosis requires the following characteristics:[10]
For patients age 20 or older, a sustained increase in heart rate ≥30 bpm within ten minutes of upright posture (tilt table test or standing) from a supine position.
For patients age 12–19, heart rate increase must be >40 bpm.
Associated with frequent symptoms of lightheadedness, palpitations, tremulousness, generalized weakness, blurred vision, or fatigue that are worse with upright posture and that improve with recumbence.
An absence of orthostatic hypotension (i.e. no sustained systolic blood pressure drop of 20 mmHg or more).
Chronic symptoms that have lasted for longer than three months.
In the absence of other disorders, medications, or functional states that are known to predispose to orthostatic tachycardia.
Alternative tests to the tilt table test are also used, such as the NASA Lean Test[87] and the adapted Autonomic Profile (aAP)[88] which require less equipment to complete.
Orthostatic intolerance
An increase in heart rate upon moving to an upright posture is known as orthostatic (upright) tachycardia (fast heart rate). It occurs without any coinciding drop in blood pressure, as that would indicate orthostatic hypotension.[34] Certain medications to treat POTS may cause orthostatic hypotension. It is accompanied by other features of orthostatic intolerance—symptoms that develop in an upright position and are relieved by reclining.[34] These orthostatic symptoms include palpitations, light-headedness, chest discomfort, shortness of breath,[34] nausea, weakness or "heaviness" in the lower legs, blurred vision, and cognitive difficulties.[1]
Testing the cardiovascular response to prolonged head-up tilting, exercise, eating, and heat stress may help determine the best strategy for managing symptoms.[41][36] POTS has also been divided into several types (see § Causes), which may benefit from distinct treatments.[89] People with neuropathic POTS show a loss of sweating in the feet during sweat tests, as well as impaired norepinephrine release in the leg,[90] but not arm.[1][89][91] This is believed to reflect peripheral sympathetic denervation in the lower limbs.[90][92][1] People with hyperadrenergic POTS show a marked increase of blood pressure and norepinephrine levels when standing, and are more likely to have from prominent palpitations, anxiety, and tachycardia.[93][94][58][89]
People with POTS can be misdiagnosed with inappropriate sinus tachycardia (IST) as they present similarly. One distinguishing feature is those with POTS rarely exhibit >100 bpm while in a supine position, while patients with IST often have a resting heart rate >100 bpm. Additionally patients with POTS display a more pronounced change in heart rate in response to postural change.[7]
Treatment
Despite numerous therapeutic interventions proposed for the management of POTS, none have received approval from the U.S. Food and Drug Administration (FDA) specifically for this indication, and no effective treatment strategies have been identified that would have been confirmed by large clinical trials.[32]
POTS treatment involves using multiple methods in combination to counteract cardiovascular dysfunction, address symptoms, and simultaneously address any associated disorders.[41][32] For most patients, water intake should be increased, especially after waking, in order to expand blood volume (reducing hypovolemia).[41][32] Eight to ten cups of water daily are recommended.[24] Increasing salt intake, by adding salt to food, taking salt tablets, or drinking sports drinks and other electrolyte solutions is an effective way to raise blood pressure by helping the body retain water. Different physicians recommend different amounts of sodium to their patients.[95] Combining these techniques with gradual physical training enhances their effect.[41][32] In some cases, when increasing oral fluids and salt intake is not enough, intravenous saline or the drug desmopressin is used to help increase fluid retention.[41][42]
Large meals worsen symptoms for some people. These people may benefit from eating small meals frequently throughout the day instead.[41]Alcohol and food high in carbohydrates can also exacerbate symptoms of orthostatic hypotension.[35] Excessive consumption of caffeine beverages should be avoided, because they can promote urine production (leading to fluid loss) and consequently hypovolemia.[41] Exposure to extreme heat may also aggravate symptoms.[24]
Prolonged physical inactivity can worsen the symptoms of POTS.[41][66] POTS may be caused or exacerbated by deconditioning.[66][96] Techniques that increase a person's capacity for exercise, such as endurance training or graded exercise therapy, can relieve symptoms for some patients.[41][66]Exercise programs can be very effective and can lead to remission in many people with POTS.[96][66][67][23][97]Aerobic exercise performed for 20 minutes a day, three times a week, is sometimes recommended for patients who can tolerate it.[95] Exercise may have the immediate effect of worsening tachycardia, especially after a meal or on a hot day.[41] In these cases, it may be easier to exercise in a semi-reclined position, such as riding a recumbent bicycle, rowing, or swimming.[41] Although exercise may be difficult initially, it becomes progressively easier as physical conditioning improves.[96][66][67]
When changing to an upright posture, finishing a meal, or concluding exercise, a sustained hand grip can briefly raise the blood pressure, possibly reducing symptoms.[41]Compression garments can also be of benefit by constricting blood pressures with external body pressure.[41]
Aggravating factors include exertion (81%), continued standing (80%), heat (79%), and after meals (42%).[98]
While people with POTS typically have normal or even elevated arterial blood pressure, the neuropathic form of POTS is presumed to constitute a selective sympathetic venous denervation.[101] In these patients the selectiveα1-adrenergic receptoragonistmidodrine may increase venous return, enhance stroke volume, and improve symptoms.[101] Midodrine should only be taken during the daylight hours as it may promote supine hypertension.[101]
Sinus node blocker ivabradine can successfully restrain heart rate in POTS without affecting blood pressure, demonstrated in approximately 60% of people with POTS treated in an open-label trial of ivabradine experienced symptom improvement.[103][104][101]
POTS has a favorable prognosis when managed appropriately.[41] Symptoms improve within five years of diagnosis for many patients, and 60% return to their original level of functioning.[41] Approximately 90% of people with POTS respond to a combination of pharmacological and physical treatments.[7] Those who develop POTS in their early to mid teens will likely respond well to a combination of physical methods as well as pharmacotherapy.[133] Outcomes are more guarded for adults newly diagnosed with POTS.[56] Some people do not recover, and a few even worsen with time.[7] The hyperadrenergic type of POTS typically requires continuous therapy.[7] If POTS is caused by another condition, outcomes depend on the prognosis of the underlying disorder.[7]
Epidemiology
The prevalence of POTS is unknown.[41] One study estimated a minimal rate of 170 POTS cases per 100,000 individuals, but the true prevalence is likely higher due to underdiagnosis.[41] Another study estimated that there are at least 500,000 cases in the United States.[6] POTS is more common in women than men, with a female-to-male ratio of 4:1.[89][134] Most people with POTS are aged between 20 and 40, with an average onset of 21.[2][89] Diagnoses of POTS beyond age 40 are rare, perhaps because symptoms improve with age.[41]
As recently stated,[135] up to one-third of POTS patients also present with Vasovagal Syncope (VVS). This ratio is probably higher if pre-Syncope patients, patients that report the symptoms of Syncope without overt fainting, were included. Given the difficulty with current autonomic measurements in quantitatively isolating and differentiating Parasympathetic (Vagal) activity from Sympathetic activity without assumption or approximation, the current direction of research and clinical assessment is understandable: perpetuating uncertainty regarding underlying cause, prescribing beta-blockers and proper daily hydration as the only therapy, not addressing the orthostatic dysfunction as the underlying cause, and recommending acceptance and associated lifestyle changes to cope.[citation needed]
Direct measures of Parasympathetic (Vagal) activity obviates the uncertainty and lack of true relief of POTS as well as VVS. For example, the hypothesis that POTS is an auto-immune disorder may be an indication that a significant number of POTS cases are indeed co-morbid with VVS. Remember the Parasympathetic Nervous System is the memory for, and controls and coordinates, the immune system. If Parasympathetic (Vagal) over-, or prolonged-, activation is chronic then portions of the immune system may remain active beyond the limits of the infection. Given that portions of the immune system are not of self, these portions remain active and continue to "feed." Once the only source of "feed" is self, the immune system begins to attack the host. This is the definition of autoimmune. This is a counter-hypothesis that may provide a simpler explanation with a more immediate plan for therapy and relief. For it may be that relieving the Vagal over-activation, will retires the self-attacking portion of the immune system, thereby relieving the autoimmunity.[citation needed]
Another example may be "Hyperadrenergic POTS." A counter hypothesis and perhaps a simpler explanation that leads to more direct therapy and improved outcomes is again the fact that POTS and VVS may be co-morbid. It is well known that Parasympathetic (Vagal) over-activation may cause secondary Sympathetic over-activation. Without direct Parasympathetic (Vagal) measures, the resulting assumption is that the secondary Sympathetic over-activation (the definition of "hyperadrenergic") is actually the primary autonomic dysfunction. Simply treating the (secondary) Sympathetic over-activation may be just treating a symptom in these cases, which may work for a while but then the body compensates and more medication is needed or the patient become unresponsive and the permanent degraded lifestyles are considered the only option. Again, this is unfortunate. Given that cases of POTS with VVS involves different portions of the nervous system (Parasympathetic and Sympathetic), and that both branches may be treated simultaneously, albeit differently, true relief of both conditions, as needed, is quite possible, and the cases of these newer hypothesized causes may be relieved with current, less expensive, and shorter-term therapy modalities.[citation needed]
Research directions
A key area for further exploration of POTS management is the autonomic nervous system and its response to the orthostatic challenge. The autonomic nervous system plays a crucial role in maintaining cardiovascular homeostasis during changes in posture. A deeper understanding of its function and the alterations that occur in POTS could provide valuable insights into potential therapeutic targets and the mechanisms of POTS treatment.[32]
History
In 1871, physician Jacob Mendes Da Costa described a condition that resembled the modern concept of POTS. He named it irritable heart syndrome.[41] Cardiologist Thomas Lewis expanded on the description, coining the term soldier's heart because it was often found among military personnel.[41] The condition came to be known as Da Costa's syndrome,[41] which is now recognized as several distinct disorders, including POTS.[citation needed]
Postural tachycardia syndrome was coined in 1982 in a description of a patient who had postural tachycardia, but not orthostatic hypotension.[41] Ronald Schondorf and Phillip A. Low of the Mayo Clinic first used the name postural orthostatic tachycardia syndrome, POTS, in 1993.[41][136]
Notable cases
British politician Nicola Blackwood revealed in March 2015 that she had been diagnosed with Ehlers–Danlos syndrome in 2013 and that she had later been diagnosed with POTS.[137] She was appointed Parliamentary Under-Secretary of State for Life Science by Prime Minister Theresa May in 2019 and given a life peerage that enabled her to take a seat in Parliament. As a junior minister, it is her responsibility to answer questions in parliament on the subjects of Health and departmental business. When answering these questions, it is customary for ministers to sit when listening to the question and then to rise to give an answer from the despatch box, thus standing up and sitting down numerous times in quick succession throughout a series of questions. On 17 June 2019, she fainted during one of these questioning sessions after standing up from a sitting position four times in the space of twelve minutes,[138] and it was suggested that her POTS was a factor in her fainting. Asked about the incident, she stated: "I was frustrated and embarrassed my body gave up on me at work... But I am grateful it gives me a chance to shine a light on a condition many others are also living with."[139]
In 2024, Taiwanese tennis player Latisha Chan revealed that she was diagnosed with POTS back in 2014 and has been receiving treatments before Summer Olympics as well. Her condition was considered career-threatening, but has had her career extended by over a decade due to external counterpulsation.[140]
In her 2024 memoir Just Add Water, Olympic gold medalist swimmer Katie Ledecky shared that she has a mild form of POTS.[141]
Related Research Articles
Orthostatic hypotension, also known as postural hypotension, is a medical condition wherein a person's blood pressure drops when they are standing up (orthostasis) or sitting down. Primary orthostatic hypotension is also often referred to as neurogenic orthostatic hypotension. The drop in blood pressure may be sudden, within 3 minutes or gradual. It is defined as a fall in systolic blood pressure of at least 20 mmHg or diastolic blood pressure of at least 10 mmHg after 3 minutes of standing. It occurs predominantly by delayed constriction of the lower body blood vessels, which is normally required to maintain adequate blood pressure when changing the position to standing. As a result, blood pools in the blood vessels of the legs for a longer period, and less is returned to the heart, thereby leading to a reduced cardiac output and inadequate blood flow to the brain.
Dysautonomia, autonomic failure, or autonomic dysfunction is a condition in which the autonomic nervous system (ANS) does not work properly. This may affect the functioning of the heart, bladder, intestines, sweat glands, pupils, and blood vessels. Dysautonomia has many causes, not all of which may be classified as neuropathic. A number of conditions can feature dysautonomia, such as Parkinson's disease, multiple system atrophy, dementia with Lewy bodies, Ehlers–Danlos syndromes, autoimmune autonomic ganglionopathy and autonomic neuropathy, HIV/AIDS, mitochondrial cytopathy, pure autonomic failure, autism, and postural orthostatic tachycardia syndrome.
Hypotension, also known as low blood pressure, is a cardiovascular condition characterized by abnormally reduced blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood and is indicated by two numbers, the systolic blood pressure and the diastolic blood pressure, which are the maximum and minimum blood pressures within the cardiac cycle, respectively. A systolic blood pressure of less than 90 millimeters of mercury (mmHg) or diastolic of less than 60 mmHg is generally considered to be hypotension. Different numbers apply to children. However, in practice, blood pressure is considered too low only if noticeable symptoms are present.
Pyridostigmine is a medication used to treat myasthenia gravis and underactive bladder. It is also used together with atropine to end the effects of neuromuscular blocking medication of the non-depolarizing type. It is also used off-label to treat some forms of Postural orthostatic tachycardia syndrome. It is typically given by mouth but can also be used by injection. The effects generally begin within 45 minutes and last up to 4 hours.
Reflex syncope is a brief loss of consciousness due to a neurologically induced drop in blood pressure and/or a decrease in heart rate. Before an affected person passes out, there may be sweating, a decreased ability to see, or ringing in the ears. Occasionally, the person may twitch while unconscious. Complications of reflex syncope include injury due to a fall.
Orthostatic intolerance (OI) is the development of symptoms when standing upright that are relieved when reclining. There are many types of orthostatic intolerance. OI can be a subcategory of dysautonomia, a disorder of the autonomic nervous system occurring when an individual stands up. Some animal species with orthostatic hypotension have evolved to cope with orthostatic disturbances.
Sinus tachycardia is a sinus rhythm of the heart, with an increased rate of electrical discharge from the sinoatrial node, resulting in a tachycardia, a heart rate that is higher than the upper limit of normal.
A tilt table test (TTT), occasionally called upright tilt testing (UTT), is a medical procedure often used to diagnose dysautonomia or syncope. Patients with symptoms of dizziness or lightheadedness, with or without a loss of consciousness (fainting), suspected to be associated with a drop in blood pressure or positional tachycardia are good candidates for this test.
Pure autonomic failure (PAF) is an uncommon, sporadic neurodegenerative condition marked by a steadily declining autonomic regulation. Bradbury and Eggleston originally described pure autonomic failure in 1925.
Inappropriate sinus tachycardia (IST) is defined as sinus tachycardia that is not caused by identifiable medical ailments, a physiological reaction, or pharmaceuticals (a diagnosis of exclusion) and is accompanied by symptoms, frequently invalidating and affecting quality of life. IST symptoms include palpitations, chest discomfort, exhaustion, shortness of breath, presyncope, and syncope.
Da Costa's syndrome, also known as soldier's heart among other names, was a syndrome or a set of symptoms similar to those of heart disease. These include fatigue upon exertion, shortness of breath, palpitations, sweating, chest pain, and sometimes orthostatic intolerance. It was originally thought to be a cardiac condition, and treated with a predecessor to modern cardiac drugs. In modern times, it is believed to represent several unrelated disorders, some of which have a known medical basis.
Julia L. Newton is Clinical Professor of Ageing and Medicine and Dean for Clinical Medicine at the School of Clinical Medical Sciences of Newcastle University in Newcastle upon Tyne, England. She is Director of MD Studies in the Faculty of Medical Sciences at Newcastle, and a member of the Pharmacogenomics & Complex Disease Genetics Research Group
Syncope, commonly known as fainting or passing out, is a loss of consciousness and muscle strength characterized by a fast onset, short duration, and spontaneous recovery. It is caused by a decrease in blood flow to the brain, typically from low blood pressure. There are sometimes symptoms before the loss of consciousness such as lightheadedness, sweating, pale skin, blurred vision, nausea, vomiting, or feeling warm. Syncope may also be associated with a short episode of muscle twitching. Psychiatric causes can also be determined when a patient experiences fear, anxiety, or panic; particularly before a stressful event, usually medical in nature. When consciousness and muscle strength are not completely lost, it is called presyncope. It is recommended that presyncope be treated the same as syncope.
Orthostatic headache is a medical condition in which a person develops a headache while vertical and the headache is relieved when horizontal. Previously it was often misdiagnosed as different primary headache disorders such as migraine or tension headaches. Increasing awareness of the symptom and its causes has prevented delayed or missed diagnosis.
Dopamine beta (β)-hydroxylase deficiency is a human medical condition involving inadequate dopamine beta-hydroxylase. It is characterized by increased amounts of serum dopamine and the absence of norepinephrine (NE) and epinephrine.
Orthostatic syncope refers to syncope resulting from a postural decrease in blood pressure, termed orthostatic hypotension.
Heat intolerance is a symptom characterized by feeling overheated in warm environments or when the surrounding environment's temperature rises. Typically, the person feels uncomfortably hot and sweats excessively.
Orthostatic hypertension is a medical condition consisting of a sudden and abrupt increase in blood pressure (BP) when a person stands up. Orthostatic hypertension is diagnosed by a rise in systolic BP of 20 mmHg or more when standing. Orthostatic diastolic hypertension is a condition in which the diastolic BP raises to 98 mmHg or over in response to standing, but this definition currently lacks clear medical consensus, so is subject to change. Orthostatic hypertension involving the systolic BP is known as systolic orthostatic hypertension.
Autoimmune autonomic ganglionopathy is a type of immune-mediated autonomic failure that is associated with antibodies against the ganglionic nicotinic acetylcholine receptor present in sympathetic, parasympathetic, and enteric ganglia. Typical symptoms include gastrointestinal dysmotility, orthostatic hypotension, and tonic pupils. Many cases have a sudden onset, but others worsen over time, resembling degenerative forms of autonomic dysfunction. For milder cases, supportive treatment is used to manage symptoms. Plasma exchange, intravenous immunoglobulin, corticosteroids, or immunosuppression have been used successfully to treat more severe cases.
Peter C. Rowe is a physician and academic. A leading researcher in chronic fatigue syndrome, he is Professor of Pediatrics, Sunshine Natural Wellbeing Foundation Professor of Chronic Fatigue and Related Disorders, and Director of the Children's Center Chronic Fatigue Clinic at Johns Hopkins University School of Medicine.
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↑ "Hospitals: Listeria: Volume 798". hansard.parliament.uk. House of Lords Hansard. 17 June 2019. Archived from the original on 6 July 2020. Retrieved 2 September 2020. Baroness Blackwood of North Oxford makes four speeches (thus standing up four times) between 5:52 PM and 6:04 PM.
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