Underlying Causes of POTS

Causes


Casues

It is important to look for possible underlying causes of your postural orthostatic tachycardia syndrome (POTS).  Some, but not all, causes of POTS are treatable.  Finding and treating those medical problems can allow you to manage your POTS symptoms better. 

There are some common tests that your physician should run to rule out other possible causes for your symptoms.

  • EKG: this records the electrical system of your heart and can be used to rule out long Q-T syndrome.  If you had a tilt table test, you likely had the EKG as part of that test.
  • Echocardiogram: this tests looks at the physical structure of your heart and can measure stroke volume and ejection fraction.  It can be used to rule out structural issues like cardiomyopathy.
  • QSART: many physicians administer this as part of the tilt table test.  It measures the sweat with mild electrical stimulation on the leg.  The QSART can be used to assess the possibility of small fiber neuropathy.
  • Autoimmune testing for other disorders that can either look like POTS or can be the underlying issue for the POTS.
    • Addison's disease
    • Lupus
    • Sjogren's syndrome

POTS often co-occurs with Ehlers-Danlos Syndrome (EDS) and mast cell activation syndrome.  These, in particular, should be considered when receiving a POTS diagnosis.

Ehlers-Danlos Syndrome (EDS)

Eighty percent of people with Ehlers-Danlos Syndrome have POTS (but not the other way around), so these two disorders can be related.  Most people with POTS have Type III EDS which is also called the hypermobility type.  There is currently no known gene for this type of EDS, so diagnosis is made using family history and clinical evaluation. To meet the criteria for EDS Type III, you must meet at least one of the major diagnostic criteria and two minor criteria.

Major Diagnostic Criteria for the Hypermobility Type of EDS
  • Joint hypermobility, which usually is confirmed by a score of five or more on the nine-point Beighton scale including:
            -One point for bending the pinkie finger backwards beyond >90º
            -One point for pulling the thumb to the forearm
            -One point for hyperextension of each elbow >10º
            -One point for hyperextension of each knee >10º
            -One point for placing the palms on the floor with the knees fully extended
  • Soft or velvety skin with normal or slightly increased extensibility.  Gently pull the skin until you feel resistance.  If the skin flap is greater than 1.5 cm, you meet the definition for increased extensibility.
  • Absence of skin or soft tissue fragility, which is suggestive of other types of EDS.
  • Molluscoid pseudotumors
  • Surgical complications, such as incisional hernia, wound splitting, or sutures tearing through tissues and failing to hold
 
Minor Diagnostic Criteria for the Hypermobility Type of EDS
  • Family history of similar features without significant skin or soft tissue fragility in a pattern consistent with autosomal dominant inheritance
  • Recurrent joint dislocations or subluxations
  • Chronic joint or limb pain
  • Easy bruising
  • Functional bowel disorders (functional gastritis, irritable bowel syndrome)
  • Neurally mediated hypotension or postural orthostatic tachycardia
  • High, narrow palate
  • Dental crowding

If you are interested in Ehlers-Danlos Syndrome, please check out these resources:

Types of Ehlers-Danlos Syndrome

Mast Cell Activation Syndrome (MCAS)

Mast cell activation syndrome (MCAS) is also commonly associated with POTS and can present in a wide variety of ways.  Mast cells are normally found throughout the body, and are most famous for their role in allergy and inflammation.  In the case of mast cell activation syndrome, the mast cells are releasing too much histamine more often than they should. Symptoms of mast cell activation syndrome include:

  • Recurrent abdominal pain
  • Flushing
  • Itching
  • Nasal congestion
  • Coughing
  • Chest tightness
  • Wheezing
  • Lightheadedness
  • Diarrhea

If you have some of these symptoms, there are blood and urine tests that can be run to confirm this diagnosis including blood tryptase levels and N-methyl histamine and  prostaglandin D2 among others in a 24 hour urine sample.  Allergists or immunologists are most likely to understand, diagnose, and treat MCAS.

Perhaps most importantly, people with mast cell activation syndrome will see an improvement in the above symptoms when they take a combination of Histamine-1 (Zyrtec, Benedryl) and Histamine-2 (Zantac) antagonists.  Talk with your doctor about trying this regimen for a week to see if your symptoms improve.

Here are some great resources about mast cell activation syndrome:

Mast cell activation syndrome: Proposed diagnostic criteria

Brain “fog,” inflammation and obesity: key aspects of neuropsychiatric disorders improved by luteolin

The vagus nerve inflammation connection

Histamine Intolerance Food List

Other Possible Underlying Causes of POTS

Here is a list of some common underlying causes for POTS.  Read through some of these links to see what sounds most like your list of symptoms and then talk with your doctor about each candidate.

Read more at:

  Dysautonomia Information Network

   Dysautonomia International