CE/CME

Postural Orthostatic Tachycardia Syndrome: A Consideration in Orthostatic Intolerance

Clinician Reviews. 2014 April;24(4):48-53

References

1. 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;21:69-72.

2. Johnson JN, Mack KJ, Kuntz NL, et al. Postural orthostatic tachcardia syndrome: a clinical review. Pediatr Neurol. 2009;42:77-85.

3. US Department of Health and Human Services, National Institutes of Health, National Institiute of Neurological Disorders and Stroke. Postural Tachycardia Syndrome Information Page. 2011. www.ninds.nih.gov/disorders/postural_tachycardia_syndrome/postural_tachycardia_syndrome.htm. Accessed March 24, 2014.

4. Agarwal AK, Garg R, Ritch A, et al. Postural orthostatic tachycardia syndrome. Postgrad Med J. 2007;83:478-480.

5. Jacob G, Costa F, Shannon JR, et al. The neuropathic postural tachycardia syndrome. N Engl J Med. 2000;343:1008-1014.

6. Staud R. Autonomic dysfunction in fibromyalgia syndrome: postural orthostatic tachycardia. Curr Rheumatol Rep. 2008;10:463-466.

7. Fu Q, VanGundy TB, Galbreath MM, et al. Cardiac origins of the postural orthostatic tachycardia syndrome. J Am Coll Cardiol. 2010;55:
2858-2868.

8. Stewart JM. Postural tachycardia syndrome and reflex syncope: similarities and differences. J Pediatr. 2009;154:481-485.

9. Lanier JB, Mote MB, Clay EC. Evaluation and management of orthostatic hypotension. Am Fam Physician. 2011;84:527-536.

10. Ojha A, McNeeley K, Heller E, et al. Orthostatic syndromes differ in syncope frequency. Am J Med. 2010;123:245-249.

11. Graham U, Ritchie KM. Reminder of important clinical lesson: postural orthostatic tachycardia syndrome. BMJ Case Rep. 2009;2009: bcr10.2008.1132. www.ncbi.nlm.nih.gov/pmc/articles/PMC3029273. Accessed March 24, 2014.

12. Mathias CJ, Low DA, Iodice V, et al. Postural tachycardia syndrome—current experience and concepts. Nat Rev Neurol. 2012;8:22-34.

13. Thanavaro JL, Thanavaro KL. Postural orthostatic tachycardia syndrome: diagnosis and treatment. Heart Lung. 2011;40:554-560.

14. Giesken B, Collins M. A 46-year-old woman with postural orthostatic tachycardia syndrome. JAAPA. 2013;26:30-34.

15. Low PA, Sandroni P, Joyner M, et al. Postural tachycardia syndrome (POTS). J Cardiovasc Electrophysiol. 2009;20:352-358.

16. Busmer L. Postural orthostatic tachycardia syndrome. Primary Health Care. 2011;21:16-20.

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HISTORY, EPIDEMIOLOGY, AND ETIOLOGY
POTS was first recognized and described during the Civil War as irritable heart syndrome or soldier’s heart due to the frequency of the condition in combat soldiers. As more was published about the condition, the list of names grew to include Da Costa syndrome, anxiety neurosis, chronic orthostatic intolerance, effort syndrome, idiopathic hypovolemia, mitral valve prolapse syndrome, orthostatic tachycardia, positional tachycardia syndrome, and finally postural orthostatic tachycardia syndrome.^5,12 Although initially described in men in the military, the condition is more frequently seen in young women from puberty to age 50. Some researchers have proposed that POTS is much more common than recent studies report; they suggest that the condition is underreported both because of the nonspecific nature of the symptoms and because it is not often included in the differential of OI.⁵

Although some researchers disagree,^7,12 most of the literature supports multiple etiologies of POTS.^1,2,13Researchers have divided the syndrome into primary and secondary causes. They have further separated primary POTS into two broad categories based on neuropathic or hyperadrenergic pathology. In both subgroups, POTS is exacerbated by dependent vasodilatation and central hypovolemia.¹¹

In the more common neuropathic POTS, a precipitating factor such as an infection, trauma, pregnancy, or surgery precedes the sudden onset of symptoms. In the majority of patients with neuropathic POTS, high normal to elevated serum norepinephrine (NE) levels are detected, as compared to “normal” controls,⁵ but known antibodies are not detected. However, in approximately 10% to 15% of patients with a reported antecedent infection, acetylcholine receptor antibodies have been detected.^2,14This form is described in the literature as immune-mediated POTS.^2,11,14,15

The less common primary hyperadrenergic POTS presents more insidiously and may have a genetic component. As documented in some families, a point mutation in the NE transporter protein has been shown to slow clearance of NE from the synaptic cleft in the central nervous system. This leads to excessive central sympathetic stimulation of the periphery.^12,13,16Developmental POTS, which presents at puberty with lower extremity neuropathy, is another form of primary POTS and resolves with maturity (see Table 1).⁶

Secondary POTS can be triggered by several known conditions including alcoholism.^12,16 Any disease or insult that damages the peripheral autonomic system may precipitate POTS. Examples include autoimmune diseases, diabetes, chemotherapy, and heavy metal poisoning.¹³ Genetic disorders have also been associated with or can contribute to secondary POTS. Joint hypermobility syndrome (JHS), also known as Ehlers-Danlos type III, is a genetic disorder characterized by defects in the structure of connective tissue.¹⁶ In JHS, the connective tissue in blood vessels is more elastic, leading to greater lower extremity pooling and decreased vasoconstrictive response to sympathetic stimulation on standing. The literature also notes that prolonged bed rest and any medications that contribute to central hypotension or interfere with compensatory peripheral vasoconstriction may precipitate POTS (see Table 2).

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