Monthly Archives: February 2014

Rare Diseases… Not So Rare

advocacy, awareness, Dysautonomia International

RDD_whiteDysautonomia International is pleased to partner with the National Organization for Rare Disorders (NORD) to celebrate Rare Disease Day today.  Did you know that overall, rare diseases are not that rare?

1 in 10 Americans has a rare disease.  That’s over 30 MILLION people, and there are even more people with rare diseases around the world.  Two thirds of people with rare diseases are children.  There are over 7,000 identified rare diseases and new diseases are discovered every year.

What is a “rare” disease?
In the United States, a disease is considered rare if it
is believed to affect fewer than 200,000 Americans.
The European Union considers rare diseases to be
those that impact Screen shot 2014-02-28 at 1.38.48 PMfewer than 1 in 2000 individuals.  Other countries have similar definitions.

What are some examples of rare diseases?
Rare diseases are present across the spectrum of medical conditions.  Most types of cancer are rare diseases. There are also rare neurological and neuromuscular diseases, metabolic diseases, chromosomal disorders, skin diseases, bone and skeletal disorders, and rare diseases affecting the heart, blood, lungs, kidneys, and other body organs and systems.

Within the realm of autonomic disorders there are several rare diseases such as Autoimmune Autonomic Ganglionopathy, Multiple System Atrophy, Pure Autonomic Failure, Familial Dysautonomia, and Dopamine Beta Hydroxylase Deficiency.

What are some of the problems experienced by people who have rare diseases?

  • Difficulty in obtaining an accurate diagnosis
  • Limited treatment options
  • Little or no research being done on the disease
  • Difficulty finding physicians or treatment centers with experience in treating a particular rare disease
  • Treatments that are generally more expensive than those for common diseases
  • Reimbursement issues related to private insurance, Medicare, and Medicaid
  • Difficulty accessing medical, social, or financial services or assistance because those making the decisions are not familiar with the disease
  • Feelings of isolation and of having been abandoned or “orphaned” by our healthcare system

What can you do to help?
Share this blog post on social media or e-mail today.  For a list of other easy ideas to help spread the word about Rare Disease Day, you can visit the following websites:
U.S. Rare Disease Day website
Global Rare Disease Day website

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New evidence of autoimmunity in POTS!

autoimmune, POTS, research

IS POTS AN AUTOIMMUNE DISEASE?

Big news this week in POTS research! Researchers from the University of Oklahoma and Vanderbilt University have identified evidence of adrenergic receptor autoantibodies in a small group of POTS patients, suggesting that POTS may be an autoimmune condition in these patients. The study was published in the Journal of the American Heart Association (JAHA). JAHA is an official journal of the American Heart Association, so this is great news for POTS awareness!

To help patients better understand what this means, Dr. David Kem from the University of Oklahoma Health Sciences Center has kindly provided Dysautonomia International with a patient friendly explanation of this complex research. Before we get to Dr. Kem’s explanation, let’s go over the basics of adrenergic receptors and autoantibodies.

Adrenergic receptors are present on the surface of cells in many different parts of the body, including the heart, blood vessels, nerves, brain, lungs, bladder, gastrointestinal tract and elsewhere. There are two main types of adrenergic receptors in the body – alpha adrenergic receptors and beta adrenergic receptors. Within the alpha and beta types, there are many different subtypes (alpha-1, alpha-2A, alpha-2B, alpha-2C, beta-1, beta-2, etc.)

Think of adrenergic receptors like a TV antenna (if you are old enough to remember when TVs had antennas!). If the TV antenna picks up a signal, it transmits a message across the screen. In adrenergic receptors the “signals” are chemicals present in the body called catecholamines (primarily epinephrine and norepinephrine). The “message” is what the catecholamine tells the receptor to do. For example, constrict a blood vessel or make the heart beat faster.

adrenergic receptor

 

Image of an adrenergic receptor, which is stimulated by catecholamines.

 

 

Antibodies are proteins created by your own immune system to protect you from pathogens, like bacteria and viruses. The human immune system can make more than 1 trillion different antibodies, each one meant to protect us from a different pathogen. Unfortunately, sometimes the antibody formation process goes awry, and the antibodies created by your immune system can turn against your own cells. These trouble-making antibodies are called autoantibodies. Autoantibodies can attack, damage or interfere with the functioning of healthy tissues and cells in your body.

Now that we all know what adrenergic receptors and autoantibodies are, here is what Dr. Kem has to say about the adrenergic receptor autoantibodies recently found in POTS patients:

POTS occurs frequently, but not exclusively, in younger females and its onset is occasionally preceded by or associated with a viral-like illness. It is more than a minor annoyance for most patients and leads to significant life changes and limitations in normal life. Our present study (Autoimmune Basis for Postural Tachycardia Syndrome) has produced data supporting the idea that production of autoantibodies, circulating proteins that normally fight such infections, have instead interacted with critical site(s) on specialized cell membrane proteins which alter their normal cell function.

These autoantibodies interfere with the system which controls the ability of blood vessels to constrict, which is needed to prevent a drop of blood pressure as a person stands. In POTS patients, this inadequate response to standing leads to a generalized increase of activity in the body’s sympathetic nerve system, which frequently normalizes the blood pressure. This increased nerve activity, however, increases the heart rate which is a prominent symptom in POTS.

We have also discovered a second group of autoantibodies in some POTS patients which directly increase the heart rate.

The combination of these two autoantibodies appears to cause the abnormal heart rate response observed in all 14 POTS patients we have tested to date for these autoantibodies.  We have previously identified similar autoantibodies in individuals diagnosed with idiopathic orthostatic hypotension (Editor’s note: see Agnostic Autoantobodies as Vasodilators in Orthostatic Hypotension: A New Mechanism and Autoantibody Activation of Beta-Adrenergic and Muscarinic Receptors Contributes to an “Autoimmune” Orthostatic Hypotension).

These autoantibodies may explain why beta blockers aren’t always effective in treating the tachycardia seen in POTS, since beta blockers fail to completely block autoantibody activity on their protein receptor and they fail to alter the partial blockade of the autoantibodies on the arteriole blood vessels that initiate the orthostatic problem.

Confirmation of our findings will require testing a larger group of POTS patients for these autoantibodies. We hope to eventually develop treatments to block these autoantibodies, without blocking the target receptor proteins at the cell surface at the same time. Such agents are in development and within a few years may be applicable in POTS. This approach may prove useful in several other diseases which are caused by similar autoantibodies.

Please note that Dr. Kem and the other researchers involved are not able to test patient blood samples for these autoantibodies outside of a research setting at this time. There are very strict federal laws that prohibit them from doing so. If such a test becomes available to the public, Dysautonomia International will be shouting it from the roof tops. Imagine that – a blood test to help diagnose POTS ? We’re looking forward to it, but there is much work to be done.

Dysautonomia International is committed to funding additional research in this area as quickly as possible. We are optimistic that this will lead to a better understanding of POTS, better ways to diagnose it, and most importantly, better ways to treat it.

If you would like to support the next phase of this exciting new research, please consider making a donation to Dysautonomia International today.  You can make a difference in the lives of millions of people around the world living with POTS!

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Postural Orthostatic Tachycardia Syndrome vs. Postural Tachycardia Syndrome

awareness, POTS

POTS or PoTS? Postural tachycardia syndrome or postural orthostatic tachycardia syndrome? What is the correct term to use?

Dysautonomia International uses the term postural orthostatic tachycardia syndrome and the acronym POTS. That’s not to say that PoTS or postural tachycardia syndrome are wrong.  Both terms and acronyms are correct, but there are several reasons why Dysautonomia International uses the longer term.

1. The original term is “postural orthostatic tachycardia syndrome.”
The first article describing POTS was written by Mayo Clinic researchers Dr. Ronald Schondorf and Dr. Philip Low in 1993. They used the term “postural orthostatic tachycardia syndrome” and the acronym POTS.

2. Slightly more journal articles have been published using “postural orthostatic tachycardia syndrome.”
The literature is pretty closely divided, but as of today’s date, if you search on PubMed.gov, the online repository of 23 million medical journal articles abstracts from the US National Library of Medicine, you will find 262 abstracts if you search for the phrase “postural orthostatic tachycardia syndrome.”  If you search for the phrase “postural tachycardia syndrome” you will find 221 abstracts.

3. The general public much more commonly uses “postural orthostatic tachycardia syndrome.”
As of today’s date, a Google search for “postural orthostatic tachycardia syndrome” returns 194,000 results.  A Google search for “postural tachycardia syndrome” only returns 38,100 results.

4. POTS patients and their doctors are more likely to use “postural orthostatic tachycardia syndrome.”
Dysautonomia International asked a large international group of patients what term they used and what term their doctors used.  Over 90% of patients responded that they and their doctors used “postural orthostatic tachycardia syndrome” and POTS.

5. Most importantly, using the term “postural orthostatic tachycardia syndrome” may help patients get better medical care.
Including the “orthostatic” word helps a medical professional, who doesn’t know what POTS is, understand a basic principle; that the person who has POTS has an orthostatic problem. Most doctors and nurses, even if they have never heard of POTS, are aware of orthostatic hypotension and maybe even orthostatic intolerance, and they have been trained how to take orthostatic vitals. Including “orthostatic” in the name of the condition gives two big hints to medical professionals that may not know what to do with the POTS patient presenting in their ambulance, ER or medical office: (1) maybe this person needs to have their blood pressure and heart rate checked in different positions, (2) maybe we need to lay this person down to prevent a faint. A person unfamiliar with POTS would not be  reminded of these clues to the nature of the diagnosis if you simply call it “postural tachycardia syndrome.”

There is no right or wrong answer, but Dysautonomia International believes that anything we can do to help POTS patients obtain better medical care should be taken into consideration.

What term do you use?

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Research Update: more proof POTS is not “all in your head”

Uncategorized

Many physicians mistake the physical symptoms of POTS, such as tachycardia, palpitations, and shortness of breath, as the signs of an anxiety disorder or some other psychological problem.  Prior research has documented that POTS is not associated with increased levels of anxiety or psychiatric disorders, that POTS symptoms are phenomenologically different and clinically distinguishable from panic disorder, and that the upright tachycardia seen POTS patients is not caused by anxiety.

Despite publication of this research, many physicians continue to misdiagnose POTS patients as having anxiety disorders or other psychiatric conditions.   While psychiatric disorders are serious health problems that require proper treatment, the treatment for these conditions is not the same as the treatment for POTS, and can sometimes make POTS symptoms worse.

New research provides additional proof that POTS is not “all in your head.”  A study recently published in Clinical Autonomic Research, Visceral sensitization in postural tachycardia syndrome, examined whether palpitations frequently reported by POTS patients were psychological or organic in origin.  Palpitations are those thumping, fluttering, pounding sensations everyone feels from time to time in their heart, but many POTS patients experienced palpitations on a regular basis, and much more so than healthy individuals.

This study found that POTS patients “did not amplify their somatic and visceral sensations compared with control subjects, indicating that they are not predisposed to exaggerating every symptom and militating against psychologic origin.”  After analyzing the data collected, the study’s author, Dr. Ramesh Khurana, concludes that the palpitations in POTS “are of an organic origin.”

However, Dr. Khurana notes that POTS patients had greater ability to discriminate the type of palpitation compared with healthy subjects, “favoring visceral hypersensitivity and a central origin of POTS symptoms.”  Visceral sensitivity is a medical term used to describe an increased sensation of pain and sensations coming from your own internal organs, more so than a normal person would experience.  By “a central origin” Dr. Khurana is referring to the central nervous system, which includes the brain and spinal cord.  He explains, “potential locations for visceral hypersensitivity include sensory receptors in the cardiovascular system, extrinsic sensory afferent neurons, spinal nociceptive neurons, medulla, midbrain raphe, hypothalamus, and cortex.”

Dr. Khurana also reminds us that POTS is heterogeneuous condition, and that the concept of visceral sensitization may not apply to every POTS patient.  He notes that palpitations did not occur in all of the POTS patients who participated in the study.

 

DysautonomiaAdvancementDysautonomia International is actively raising funds to support additional research on POTS.  If you would like to support POTS research, please visit our donation page today.

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