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Dysautonomia: POTS Diagnostic ...

With so few doctors specialized in the treatment of autonomic disorders, many doctors are aiming to diagnose and treat Postural Orthostatic Tachycardia Syndrome without a comprehensive background in this field.  Patients are finding that there is some varience in the diagnostic criterion these doctors are using, and perhaps some confusion about what is and is not part of the diagnosis of POTS.  Here we have amassed quotes from publications by top dysautonomia/syncope/POTS specialists to which doctors and patients may refer for clarification as needed.  Please note that provided here are brief quotes which should address the gist of diagnostic disputes but in most instances much more extensive information that may be of use is available in the full articles; it is highly recommended that patients/physicians access the full sources if possible for context and further information.

 


From Dr. Grubb, one of the most published and renowned experts on syncope and related disorders in the United States:

 

"POTS is currently defined as the presence of symptoms of orthostatic intolerance associated with a heart rate increase of 30 bpm (or rate that exceeds 120 bpm) that occurs within the first 10 minutes of standing or upright tilt, not associated with other chronic debilitating conditions such as prolonged bed rest or the use of medications known to diminish vascular or autonomic tone.  ... It should be noted that many patients with orthostatic intolerance due to POTS will not demonstrate orthostatic hypotension (defined as fall of >20/10 mm Hg on standing). Instead, they may display no change, a small decline, or even a modest increase in blood pressure."  [Emphasis added.]

 

-Grubb, Blair P.  Postural Tachycardia Syndrome. Circulation 2008;117;2814-2817  DOI: 10.1161/CIRCULATIONAHA.107.761643  Downloaded from circ.ahajournals.org by on April 2, 2009

-http://circ.ahajournals.org/cgi/content/full/117/21/2814

 

**This article includes discussion of specific symptoms associated with the orthostatic intolerance of POTS as well as the severity of disability that can accompany POTS and can be particularly useful for doctors not well-versed in the syndrome.**

 

Medical textbooks by, or including chapters by, Dr. Blair Grubb (not an exhaustive list):

Syncope:  Mechanisms and Management

PanVascular Medicine (Chapter on Neurovegetation Regulation of the Vascular System)

The Fainting Phenomenon: Understanding Why People Faint and What to do about It (Suitable for Laymen)

Syncope and Transient Loss of Consciousness: Multidisciplinary Management (Chapter on The impact of syncope and TLOC on quality of life)


From Dr. Mathias, an autonomic expert from the UK who is published and renowned both at home and in the US:

 

"Orthostatic intolerance with posturally induced tachycardia

Orthostatic intolerance may occur without orthostatic hypotension. In some there is a substantial rise in heart rate, of over 30 beats per minute, favouring the “postural tachycardia syndrome” (PoTS) or “neuropathic postural tachycardia syndrome” (NPTS). It predominantly affects women below the age of 50 years. Symptoms include pronounced dizziness on postural change or with modest exertion, usually without syncope. Their lives often are disrupted disproportionately."

 

-Mathias, Christopher J. Autonomic diseases: clinical features and laboratory evaluation.  J. Neurol. Neurosurg. Psychiatry 2003;74;iii31-iii41  doi:10.1136/jnnp.74.suppl_3.iii31  Downloaded from jnnp.bmj.com on 7 September 2009

-http://jnnp.bmj.com/cgi/content/full/74/suppl_3/iii31

-Adapted from Mathias CJ. Autonomic disorders and their recognition. N Engl J Med 1997;336:721–4.

 

**This article discusses many different types of autonomic disorders, rather than just OI syndromes or POTS specifically.**

 

Medical textbooks by, or including chapters by, Dr. Christopher Mathias (not an exhaustive list):

Autonomic Failure: A Textbook of Clinical Disorders of the Autonomic Nervous System

Neurology: A Queen Square Textbook (Chapter on Autonomic Dysfunction)

Syncope and Transient Loss of Consciousness: Multidisciplinary Management (Chapter on Intolerance to upright posture in autonomic failure and the postural tachycardia syndrome: assessment and treatment strategies)

Primer on the Autonomic Nervous System (Chapter on Autonomic Disturbances in Spinal Cord Injuries)


From the Mayo Clinic, including world-renowned autonomic specialist, Dr. Phillip A. Low

 

"When autonomic failure is incomplete, compensatory autonomic overreaction occurs, resulting in symptoms such as palpitations, tremulousness, vasomotor symptoms (eg, coldness, acrocyanosis), and nausea. Thus almost paradoxically, patients with partial dysautonomia may be more clinically symptomatic than those with more complete autonomic dysfunction.
Patients with the postural tachycardia syndrome (POTS) [2] are characterized by excessive orthostatic tachycardia without hypotension associated with lightheadedness, palpitations, tremulousness, and nausea. Other symptoms that occur while in the upright position and which resolve themselves while supine include tunnel vision, weakness, fatigue, difficulty breathing, and pains (chest, acral). The intensity and frequency of symptoms is often variable and in some instances may occur even when the patient is supine."  [Emphasis added.]

 

 -Low, Phillip A., Ronald Schondorf, & Teresa A. Rummans.  Why Do Patients Have Orthostatic Symptoms in POTS? Clinical Autonomic Research 2001, 11:223-224  DOI: 10.1007/BF02298952  Downloaded from www.springerlink.com on 7 September 2009

-http://www.springerlink.com/content/a4212711046r48x4/

 

"Postural tachycardia syndrome (POTS) is defined as the development of orthostatic symptoms associated with a heart rate (HR) increment of 30 or more beats per minute (bpm).  We chose these practical and reasonable criteria rather than requiring an increment that relates to our normative data by age and gender.  Considering the age range of most patients with POTS (15 to 40 years), an increment of 30 bpm exceeds the 99th percentile of 271 Mayo control subjects from 10 to 83 years old, but is more stringent in terms of the absolute orthostatic HR.  The more florid cases have a standing HR of 120 bpm or more (59,87).  Caution is recommended with teens for whom these criteria may be too lax.  ... Most patients with orthostatic intolerance do not have florid autonomic failure and do not have orthostatic hypotension.  ... Orthostatic symptoms consist of symptoms of reduced cerebral perfusion together with those of sympathetic activation."  [Emphasis added.]

 

-Low, Phillip A.  Clinical Autonomic Disorders.  Philidelphia:  Lippincott Williams & Wilkins, 2008.  pp. 515-16.

-See below for link to text on Amazon.com

 

**This chapter on POTS, like the aforementioned article by Grubb, is very comprehensive in its coverage of the associated symptoms as well as the mechanisms involved.  It might not be an understatement to say this would be indispensible reading material for an inexperienced physician trying to treat a POTS patient.  On the other hand, it is not so technical as to be inaccessible to the layman.**

 

Medical textbooks by, or including chapters by, Dr. Phillip Low (not an exhaustive list):

Clinical Autonomic Disorders

Clinical Autonomic Disorders: Evaluation and Management (Different enough from aforementioned later publication to warrant separate mention; compare Tables of Contents in "Look Inside" feature on Amazon to see the differences)

Primer on the Autonomic Nervous System (Many chapters, too numerous to list individually here)

 


From Dr. Shamil Yusuf, a British Heart Foundation Research Fellow in Cardiology:

 

"Postural orthostatic tachycardia syndrome (POTS) is an abnormal sinus tachycardia which is triggered by orthostasis and relieved by recumbency.7 There is no significant hypotension during upright posture and neither an underlying cause nor clinical signs of autonomic neuropathy should be present.7, 8" [Emphasis added: the portion in bold re: exclusionary criterion for the diagnosis is disputed.  Please see note below.]

 

-Yusuf, Shamil & A. John Camm. Deciphering the Sinus Tachycardias. Clin. Cardiol. 28, 267–276 (2005)

-http://www.iranep.org/Articles/Sinus%20tach%20GP%20Clin%20Cardiol%202005.pdf

 

*Note, the footnotes to his statement re: no signs of autonomic neuropathy being present point to an article by Dr. Low from 1995 and Low's book (see above) CAD: Evaluation and Management from 1997

 

Dr. Low's 2008 book (CAD, see above) states that "About 59% of patients with POTS have an autonomic neuropathy (86,87,104)." (p.516)  His footnotes point to two articles that he coauthored dating back all the way to 1993 as well as a Mayo Clinic Proceedings publication from 2007.  If you can follow my logic here, if Low is pointing back to his own work in 1993 as evidence FOR autonomic neuropathy being comorbid with POTS and he was obviously still espousing this view in 2007 and 2008, I believe that Dr. Yusuf may have misinterpreted Dr. Low's publications from 1995 and 1997 in concluding that they supported using the presence of autonomic neuropathy as an exclusionary criteria when diagnosing POTS. 

 

In fact, one of the two Low publications that Yusuf cites in favor of stating "nor [should] clinical signs of autonomic neuropathy ... be present" in POTS, says quite clearly in the midst of the very pages Yusuf lists in his footnote ("681-697"):  "About half the patients with POTS have an autonomic neuropathy"  (Low 1997, CAD: E&M, p. 682).

 


From the highly published and respected Dr. Satish R. Raj at Vanderbilt:

 

"Patients met criteria for POTS11 in that they developed symptoms of orthostatic intolerance accompanied by a heart rate rise ≥30 bpm (or a rate that exceeded 120 bpm) within the first 10 minutes of standing or head-up tilt in the absence of orthostatic hypotension (a fall in blood pressure of >20/10 mm Hg) and with an elevated standing norepinephrine value (>2.81 nmol/L [475 pg/mL])."  [Emphasis added.  Note that this differs from the criteria presented by other specialists, which may possibly be in part reflective of the fact that it is not yet standard practice to even test standing norepinephrine levels, making it impractical to put that into current practice as a diagnostic standard.  Or it may represent a difference of opinion between specialists/clinics.]

 

-Raj, Satish R., Bonnie K. Black, Italo Biaggioni, Paul A. Harris, & David Robertson. Acetylcholinesterase Inhibition Improves Tachycardia in Postural Tachycardia Syndrome. Circulation. 2005;111:2734-2740. Published online before print May 23, 2005, doi: 10.1161/CIRCULATIONAHA.104.497594   Downloaded from circ.ahajournals.org by on September 7, 2009

-http://circ.ahajournals.org/cgi/content/full/111/21/2734

 

"in POTS, blood pressure is typically maintained on standing or may even increase. Heart rate rises more than 30 bpm and symptoms reminiscent of impaired cerebral perfusion may develop.  ... POTS is defined (Table 1) as the presence of symptoms of orthostatic intolerance for at least 6 months accompanied by a heart rate increase of at least 30 beats/min within 5-30 minutes of assuming an upright posture. This should occur in the absence of orthostatic hypotension (a fall in blood pressure >20/10 mmHg). The syndrome must occur in the absence of prolonged bed rest, medications that impair autonomic regulation (such as vasodilators, diuretics, antidepressants or anxiolytic agents), or any other chronic debilitating disorders that might cause tachycardia (such as dehydration, anemia or hyperthyroidism). It is important to recognize that this syndrome is typically disabling. Hence, the mere observation of orthostatic tachycardia is not, by itself, sufficient to make the diagnosis of POTS.  ... While pre-syncope is common in these patients, only a minority (~30%) actually pass out."  [Emphasis added.  Here we see a stipulation of symptoms present for at least six months, where other experts typically specify a minimum three month duration if they specify at all.  This six month value seems to be unique to Vanderbilt publications.  This description also includes an estimation of syncope comorbidity, which may be helpful for some patients.]

 

-Raj, Satish R. The Postural Tachycardia Syndrome (POTS): Pathophysiology, Diagnosis & Management. Indian Pacing Electrophysiol. J. 2006;6(2):84-99.  Downloaded from www.ipej.org on August 5, 2009

-http://www.ipej.org/0602/raj.htm

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