Peer Reviewed

Case In Point

Postural Orthostatic Tachycardia Syndrome: When Standing Tall Makes You Feel Like You Are Going to Fall

Volume 60 - Issue 5 - May 2020

AUTHORS:
Craig Hricz, MPAS, PA-C • Pooja Kundargi, BS, PA-S

AFFILIATIONS:
School of Physician Assistant Studies, Massachusetts College of Pharmacy and Health Sciences, Manchester, New Hampshire

CITATION:
Hricz C, Kundargi P. Postural orthostatic tachycardia syndrome: when standing tall makes you feel like you are going to fall. Consultant. 2020;60(5):e3. doi:10.25270/con.2020.05.00003

DISCLOSURES:
The authors report no relevant financial relationships.

CORRESPONDENCE:
Craig Hricz, MPAS, PA-C, Associate Professor, School of Physician Assistant Studies, MCPHS, 1260 Elm St, Manchester, NH 03101 (craig.hricz@mcphs.edu)

 

An 89-year-old man presented to the emergency department (ED) after having been sent from his primary care provider’s office over concern for possible dehydration, which had caused the patient to become weak and dizzy.

On presentation to the ED, the patient reported experiencing dizziness and lightheadedness, primarily with standing, which he had first begun to notice approximately 3 weeks prior. One week prior to this visit, he also had been assessed in the ED for similar symptoms and had been given intravenous fluids, but he had noticed no change since then. A few days after that visit, he had been assessed by his primary care provider, at which point his atenolol and valsartan were held, but still his symptoms persisted. Since then, an episode of dizziness and lightheadedness had resulted in a ground-level fall, causing him to strike his head and to land on his left hip. He denied any loss of consciousness. Prior to the past 3 weeks of these symptoms, the patient had been very independent and active.

History. His history was positive for the recent development of a sacral bedsore. He denied recent vomiting, diarrhea, fever, weight loss, chest pains, prominent palpitations, dark stools, decreased oral intake, focal weakness or numbness, headache, vision changes, syncope, and urinary frequency or urgency. His medical history included coronary artery disease with stent placement, along with chronic kidney disease, type 2 diabetes mellitus, dyslipidemia, hypertension, and peripheral neuropathy.

His current medications were aspirin, atorvastatin, insulin aspart, insulin detemir, saxagliptin, magnesium oxide, and a multivitamin. Tamsulosin, atenolol, and valsartan had been held for several days prior to evaluation in the ED. He was a former smoker, and he denied alcohol or drug use. He lived with family.

Physical examination. His vital signs were within normal limits, including a pulse rate of 77 beats/min, respiratory rate of 20 breaths/min, blood pressure of 135/57 mm Hg, oxygen saturation of 98%, and temperature of 36.4°C. He was in no apparent distress and was cooperative, with an appropriate affect. Findings of a review of systems (including head, eyes, ears, nose, and throat; pulmonary system; cardiovascular system; musculoskeletal system; and abdomen) were normal and noncontributory. Aside from a stage 2 sacral decubitus, skin examination findings were otherwise normal, with no erythema or rashes.

Neurologic examination showed sensation intact to light touch and +5 strength in the upper and lower extremities bilaterally. His gait was not assessed during the initial examination.

Orthostatic vital signs were assessed and showed an increased standing heart rate of 152 beats/min but only a mild drop in blood pressure. He required 1-person assistance with ambulation as a result of seemingly mild generalized weakness, and he was persistently leaning backwards, thus he was considered at risk for a fall.

Diagnostic tests. Results of a comprehensive metabolic panel included an elevated glucose level of 311 mg/dL, an elevated blood urea nitrogen level of 28 mg/dL, and a creatinine level of 1.3 mg/dL, but were otherwise unremarkable, including the magnesium level. Results of a complete blood cell count (CBC) showed a low hemoglobin level of 11.4 g/dL and a low hematocrit level of 34.1% but were otherwise unremarkable. Other noteworthy test results included a low lactate level of 2.1 mg/dL, a low troponin level of 0.019 ng/mL, and a thyrotropin level 1.73 mIU/L. Urinalysis results were unremarkable.

Electrocardiography (ECG) results showed sinus bradycardia with first-degree block at 55 beats/min. Diffuse 1-mm ST segment elevations were noted, similar to ECG results from 1 year prior, but with new right bundle branch block. Findings of radiographs of the chest and left hip and computed tomography scans of the head were unremarkable.

The differential diagnosis included benign positional vertigo, stroke, subdural hematoma, urinary tract infection, hypovolemia, primary anemia or gastrointestinal bleed with secondary anemia, electrolyte disorder, arrhythmia, postural orthostatic tachycardia syndrome, and carotid sinus sensitivity.

The patient was admitted to the telemetry unit. Magnetic resonance imaging of the brain revealed global atrophy and nonspecific white matter changes. Echocardiography revealed an ejection fraction of 72%, normal ventricular size and function, and mild aortic, mitral, and pulmonic valve regurgitation. Carotid duplex ultrasonography demonstrated no significant stenosis. Occupational and physical therapy assessments were performed. The patient was discharged home after a 3-day hospitalization.

DISCUSSION

This patient’s case is consistent with postural orthostatic tachycardia syndrome (POTS). As defined by the National Institutes of Health, POTS is an orthostatic intolerance disorder consisting of lightheadedness or fainting accompanied by a rapid increase in heartbeat of more than 30 beats/min or a heart rate that exceeds 120 beats/min within 10 minutes of standing up from a supine position.1 The American College of Cardiology adds “in the absence of orthostatic hypotension” to the definition.2

Pathophysiology. When the circulatory system is functioning normally, approximately 500 mL of an individual’s blood volume travels from the thorax to the abdomen and lower extremities within 10 seconds of going from supine to standing. The result is a rapid decrease in preload and, ultimately, cardiac output. Receptors in the aortic arch, carotids, heart, and lungs respond to this low output by triggering arterial vasoconstriction and increasing the heart rate in an attempt to maintain systolic blood pressure. The end result is a 10- to 15-beat/min elevation of the heart rate and a slight drop in the diastolic pressure of approximately 10 mm Hg for less than 1 minute.3 POTS is a dysregulation of this process due to an inability of the autonomic nervous system to initiate arteriole constriction in the lower extremities, resulting in excess blood volume being allowed to flow into these areas. The body compensates by increasing norepinephrine levels, which results in an elevated heart rate and venous constriction.4,5 Some degree of hypotension is also possible during these events, but not to the extent or regularity that would be expected in an individual who is strictly hypovolemic.

Etiology and epidemiology. POTS diagnoses are frequently delayed as a result of underrecognition by providers, with an average of nearly 6 years from initial encounter until diagnosis. Delays in diagnosis can lead to unnecessary tests, resource utilization, loss of income from missed work, anxiety, depression, and erroneous diagnoses. Women are affected 5 times more often than men, and the mean age at onset is approximately 30 years, but nearly half of all patients have reported symptom onset after the age of 19 years.6 One study of 7- to 18-year-olds confirmed a gender predilection of 56.8% girls to 43.2% boys.7

Many cases of POTS are thought to be the result of an autoimmune process triggered by recent illness or recent stressors such as trauma, surgical procedures, or pregnancy.6 These processes trigger the production of autoantibodies that affect various receptors responsible for arteriole constriction and blunt the effect of norepinephrine.8 The end result is an increased heart rate upon standing and potentially less-than-expected hypotension response compared with an individual who is hypovolemic. Additionally, one study demonstrated that individuals with a history of joint hypermobility syndrome (JHS) had high rates of developing POTS.9,10 In the adolescent population, significant differences of daily water intake, hours of sleep, and supine heart rate were found to be key risk factors for children with POTS compared with those without it.7

Several forms of POTS have been identified, which are subdivided into primary and secondary subtypes. The primary class (not associated with another disease process) subtypes include neuropathic POTS, developmental POTS and hyperadrenergic POTS.

Neuropathic POTS, also known as partial dysautonomia (PD), is the most common form. This form is defined by insufficient vascular constriction peripherally when performing an orthostatic test. PD-type POTS favors women to men by a 5 to 1 ratio. Mainly seen following viral induced fevers, pregnancy, and immunization, this subtype is characterized by poor peripheral constriction resulting in pooling in the venous system, ultimately leading to poor blood pressure maintenance. The body attempts to adapt to blood flow regulation via skeletal muscle pump, but due its inadequacy, yields disproportionate perfusion.9

Developmental POTS is commonly seen in adolescents, with a mean age of onset of 14 years. This orthostatic tachycardia is thought to follow rapid growth and immature peripheral blood flow, leading to common POTS symptoms such as headaches and lightheadedness. These symptoms generally resolve as the adolescent grows older.11

Hyperadrenergic POTS, a less common form, has a slower onset with symptoms such as anxiety, tremors, and clammy hands and feet. In addition, patients with it can experience migraines, as well as gastrointestinal tract symptoms secondary to orthostasis.12 It is theorized to be related to a genetic point mutation with dysfunctional norepinephrine reuptake transporters, thereby prolonging the adrenergic responses from norepinephrine.9

The secondary class subtypes of POTS are caused by an underlying disease process. In particular, JHS is associated with the development of POTS in up to 70% of cases. In these patients, specific cartilage types are replaced by those with more elasticity, resulting in weaker tissue and poor venous vessel structure. Ehlers-Danlos syndrome, an inheritable syndrome that is considered a subtype of JHS, has been associated with inadequate control of heart rate and blood pressure, further enhancing the potential risk factors for this syndrome.9,11,13,14 Other secondary causes include diabetes, multiple sclerosis, Parkinson disease, and even chemotherapy.9

Symptoms and physical examination. POTS is most recognizable by the onset of sinus tachycardia and dizziness upon standing, which is generally alleviated by lying down or leaning against a surface.15 Other causative factors include exercise, eating, heat exposure, and menstruation. The most common reported symptoms are outlined in Table 1.5

Table 1

 

While many of the symptoms are subjective, dermatologic findings are frequently reported in patients with POTS. These include Raynaud phenomenon, urticaria, pruritis, and dependent acrocyanosis, also referred to as livedo reticularis.16 Livedo reticularis is a blotchy, mottled, or lacelike appearance ranging from red to blue to purple in color.17 In patients with POTS, this can be seen transiently in the legs and feet.

In addition to considering physical signs and symptoms, providers must also consider the psychiatric symptoms that patients with POTS may present with. Dysregulation of the autonomic nervous system also occurs in many psychiatric disorders, resulting in elevated norepinephrine levels similar to those seen in POTS. Providers must therefore be aware of potential psychiatric differential diagnoses such as generalized anxiety disorder, panic attacks, depression, and personality disorders when patients present with these symptoms.6 This overlap of symptoms is another reason for potential delays in diagnosis.

Workup. The consensus criteria for the diagnosis of POTS is a heart rate increase of at least 30 beats/min (40 beats/min for patients aged 12-19) within 10 minutes of adjusting from supine to an upright position without an accompanying drop in systolic blood pressure of more than 20 mm Hg. The increased heart rate in many patients exceeds 120 beats/min.18 The sinus tachycardia is usually accompanied by the symptoms summarized in Table 1. These criteria are most accurately obtained through the use of a tilt-table test. Other criteria that have been proposed include improved symptoms with recumbence, recurrent symptoms for more than 6 months, and standing norepinephrine levels of 600 pg/mL or more (in hyperadrenergic POTS).9,19

The gold standard for confirming a suspected diagnosis of POTS is the automated tilt-table test, also referred to as the head-upright test. The test is a reliable method of inducing symptoms to confirm the diagnosis of cardiovascular autonomic disorders by testing for an increased heart rate after an orthostatic stressor.5,19,20 During this test, a patient first lies supine on a specially designed table fitted with foot supports and torso restraints for a minimum of 5 minutes; if venous cannulation is simultaneously performed, the supine time is extended to 20 minutes. Following this supine period, the angle must be adjusted to 60° to 70° head-up tilt for 20 to 45 minutes.5 In addition to cardiac rhythm monitoring, continuous pulse and blood pressure measurements are obtained using the Penaz technique, which uses a photoplethysmography sensor placed on a finger, providing instant feedback to the pressure cuff. The cuff pressure is automatically adjusted with the goal of keeping the artery in a partially opened state for up to 2 hours if necessary. The pressure adjustments required to keep the artery partially opened are used to derive systolic and diastolic pressures.21 The resulting changes in heart rate and blood pressure are recorded for further evaluation.

Due to many disorders that share common symptoms with POTS, it is crucial to obtain a detailed history and consider other parasympathetic and sympathetic effects on the cardiovascular system to rule out more-threatening forms of autonomic nervous system failure.14 A detailed history should include exacerbating/relieving factors (including heat exposure, diet and exercise, recent illness or surgery) and family history. Table 2 summarizes the differential diagnoses that can mimic or contribute to POTS symptoms, along with the corresponding evaluation options and a brief discussion of how the test can help differentiate between the two.14,20-22 In select patients, additional workup as recommended by the Heart Rhythm Society include a CBC, a thyroid panel, autonomic testing, an exercise stress test, and transthoracic echocardiography.19

Table 2

 

Treatment. In addition to addressing medication-related factors, dehydration, or anemia that may be exacerbating underlying POTS, first-line treatment options include the following:11,23,24

  • Avoidance of triggers such as prolonged recumbent position, hot environments, and large meals.
  • Daily water intake of 2 to 3 L.
  • Daily salt intake of 8000 to 10,000 mg.
  • Regular wearing of compression stockings with 30 to 40 mm Hg of counterpressure.
  • Elevating the head of the bed 10 to 15 cm.
  • A reclined exercise regimen including rowing, recumbent biking, and swimming should be strongly encouraged.

Additional treatment options include the following:5,9,14,23

  • Propranolol, 10 to 20 mg 3 or 4 times daily, has been shown to minimize standing tachycardia.
  • Fludrocortisone, 0.05 to 0.2 mg once daily, expands plasma volume by increasing sodium retention.
  • Midodrine, 2.5 to 10 mg 3 times daily, causes arterial and venous constriction and is added to fludrocortisone for persistent symptoms, with first daily dose taken 15 minutes prior to getting out of bed.
  • Pyridostigmine, 30 mg once daily, increases levels of acetylcholine, which controls tachycardia response to standing.

A number of medications have been studied but have limited data to support their use and are more appropriate for refractory cases of POTS and in consultation with an expert. These include methyldopa, clonidine, phenobarbital, ivabradine, octreotide, erythropoietin, desmopressin, methylphenidate, selective serotonin-reuptake inhibitors, and serotonin-norepinephrine reuptake inhibitors.

None of these medications are approved by the Food and Drug Administration for POTS therapy, and there does not seem to be an overwhelming consensus on whether propranolol, fludrocortisone, midodrine, or pyridostigmine should be the initial drug of choice. All 4 of these medications are class IIb recommendations for general use. Clonidine and methyldopa are also class IIb recommendations and are suggested for use in patients with hyperadrenergic features, which include a greater than 10 mm Hg rise in blood pressure with standing, norepinephrine levels greater than 600 pg/mL, or prominent symptoms such as palpitations, anxiety, or tremor.19 Medication decisions depend on a patients’ comorbid medical conditions or medications as well as tolerance of adverse effects.

Cognitive-behavioral therapy that employs relaxation techniques and biofeedback may be of benefit, especially in the younger population or for those with comorbid psychiatric conditions.

Prognosis. The prognosis within the first 2 to 5 years after diagnosis is somewhat promising, with approximately 50% of patients who develop POTS secondary to a viral illness experiencing little or no symptoms or restrictions to daily activities. The other half of patients experience partial improvement, or in some cases, worsening of symptoms. Younger age is associated with a better prognosis. The long-term prognosis is less certain.9 Encouraging the continuation of a regular exercise program in addition to the other supportive measures discussed above will help improve quality of life in most patients.

REFERENCES:

  1. Postural tachycardia syndrome information page. National Institute of Neurological Disorders and Stroke. https://www.ninds.nih.gov/Disorders/All-Disorders/Postural-Tachycardia-Syndrome-Information-Page. Updated March 27, 2019. Accessed February 4, 2020.
  2. Bryarly M, Phillips LT, Fu Q, Vernino S, Levine BD. Postural orthostatic tachycardia syndrome: JACC Focus Seminar. J Am Coll Cardiol. 2019;73(10):1207-1228. doi:10.1016/j.jacc.2018.11.059
  3. Kanjwal Y, Kosinski D, Grubb BP. The postural orthostatic tachycardia syndrome: definitions, diagnosis, and management. Pacing Clin Electrophysiol. 2003;26(8):1747-1757. doi:10.1046/j.1460-9592.200t01-1-00262.x
  4. Grubb BP. Postural tachycardia syndrome. Circulation. 2008;117(21):2814-2817. doi:10.1161/CIRCULATIONAHA.107.761643
  5. Carew S, Connor MO, Cooke J, et al. A review of postural orthostatic tachycardia syndrome. Europace. 2009;11(1):18-2 doi:10.1093/europace/eun324
  6. Schmidt LL, Karabin BL, Malone AC. Postural orthostatic tachycardia syndrome (POTS): assess, diagnose, and evaluate for POTS treatment (ADEPT). Integr Med Int. 2017;4(3-4):142-153. doi:10.1159/000484205
  7. Lin J, Han Z, Li X, et al. Risk factors for postural tachycardia syndrome in children and adolescents. PLoS ONE. 2014;9(12): e113625. doi:10.1371/journal.pone.0113625
  8. Li H, Yu X, Liles C, et al. Autoimmune basis for postural tachycardia syndrome. J Am Heart Assoc. 2014;3(1):e000755. doi:10.1161/JAHA.113.000755
  9. Conner R, Sheikh M, Grubb B. Postural orthostatic tachycardia syndrome (POTS): evaluation and management. Br J Med Pract. 2012;5(4):a540.
  10. Mandel D, Askari AD, J. Malemud C, Kaso A. Joint hypermobility syndrome and postural orthostatic tachycardia syndrome (HyPOTS). Biomed Res Clin Pract. 2017;2(2). doi:15761/BRCP.1000132
  11. Mohr LD. A case report and review of postural orthostatic syndrome in an adolescent. J Pediatr Health Care. 2017;31(6):717-723. doi:10.1016/j.pedhc.2017.04.013
  12. Chelimsky G, Chelimsky T. The gastrointestinal symptoms present in patients with postural tachycardia syndrome: A review of the literature and overview of treatment. Auton Neurosci. 2018;215:70-77. doi:10.1016/j.autneu.2018.09.003
  13. Kumar B, Lenert P. Joint hypermobility syndrome: recognizing a commonly overlooked cause of chronic pain. Am J Med. 2017;130(6):640-647. doi:10.1016/j.amjmed.2017.02.013
  14. Garland EM, Celedonio JE, Raj SR. Postural tachycardia syndrome: beyond orthostatic intolerance. Curr Neurol Neurosci Rep. 2015;15(9):60. doi:10.1007/s11910-015-0583-8
  15. Low PA, Schondorf R, Rummans TA. Why do patients have orthostatic symptoms in POTS? Clin Auton Res. 2001;11(4):223-224. doi:10.1007/bf02298952
  16. Huang H, Deb A, Culbertson C, Morgenshtern K, DePold Hohler A. Dermatological manifestations of postural tachycardia syndrome are common and diverse. J Clin Neurol. 2016;12(1):75-78. doi:10.3988/jcn.2012.1.75
  17. Sajjan VV, Lunge S, Swamy MB, Pandit AM. Livedo reticularis: a review of the literature. Indian Dermatol Online J. 2015;6(5):315-321. doi:10.4103/2229-5178.164493
  18. Freeman R, Wieling W, Axelrod FB, et al. Consensus statement on the definition of orthostatic hypotension, neurally mediated syncope and the postural tachycardia syndrome. Clin Auton Res. 2011;21(2):69-72. doi:10.1007/s10286-011-0119-5
  19. Sheldon RS, Grubb BP II, Olshansky B, et al. 2015 Heart Rhythm Society expert consensus statement on the diagnosis and treatment of postural tachycardia syndrome, inappropriate sinus tachycardia, and vasovagal syncope. Heart Rhythm. 2015;12(6):e41-e63. doi:10.1016/j.hrthm.2015.03.029
  20. Raj SR. Postural tachycardia syndrome (POTS). Circulation. 2013;127(23):2336-2342. doi:10.1161/CIRCULATIONAHA.112.144501
  21. Muenter Swift N, Charkoudian N, Dotson RM, Suarez GA, Low PA. Baroreflex control of muscle sympathetic nerve activity in postural orthostatic tachycardia syndrome. Am J Physiol Heart Circ Physiol. 2005;289(3):H1226-H1233. doi:10.1152/ajpheart.01243.2004
  22. Ketch T, Biaggioni I, Robertson R, Robertson D. Four faces of baroreflex failure: hypertensive crisis, volatile hypertension, orthostatic tachycardia, and malignant vagotonia. Circulation. 2002;105(21):2518-2523. doi:10.1161/01.cir.0000017186.52382.f4
  23. Raj SR, Levine BD. Postural tachycardia syndrome (POTS) diagnosis and treatment: basics and new developments. American College of Cardiology. https://www.acc.org/latest-in-cardiology/articles/2016/01/25/14/01/postural-tachycardia-syndrome-pots-diagnosis-and-treatment-basics-and-new-developments. Published February 7, 2013. Accessed February 4, 2020.
  24. Kizilbash SJ, Ahrens SP, Bruce BK, et al. Adolescent fatigue, POTS, and recovery: a guide for clinicians. Curr Probl Pediatr Adolesc Health Care. 2014;44(5):108-133. doi:10.1016/j.cppeds.2013.12.014