POTS falls under the more general umbrella of disorders called dysautonomia. POTS, like all dysautonomias, is characterized by dysfunction of the autonomic nervous system which controls many “automatic” physiological functions including blood pressure, heart rate, blood vessel and pupil diameter, movements of the digestive tract, and body temperature. In dysautonomia, the person can suffer from a wide range of symptoms that are ultimately connected by the dysfunction of the autonomic nervous system.
One of the hallmark symptoms of POTS is orthostatic intolerance. Because the autonomic nervous system is not functioning correctly, the constriction of blood vessels that normally occurs when we transition from sitting to standing is decreased or absent. This lack of vessel constriction leads to blood pooling in the legs and abdomen, which results in a shortage of blood in the heart and brain. The shortage of blood in the brain upon standing can result in dizziness, light-headedness, and possibly fainting (1) Because of this, it is important for an individual with POTS to sit on the edge of the bed or recliner for 10-15 seconds before standing to give the body time to respond to the change in position.
While anyone can develop POTS, approximately 75% of those diagnosed are women between the ages of 15 and 50 (2). POTS can be triggered by a variety of life stressors including pregnancy, major surgery, trauma, or a viral infection like mononucleosis or Lyme disease (2). The question is why POTS occurs in only a few women who start families, have mono, or get in a car accident. Unfortunately, there is no answer to that question at present.
POTS is not a rare disorder (rare is defined as less than 200,000 people in the US with that diagnosis). The estimate in the US is that 170/100,000 in the general population have POTS (4), about 540,000 Americans. It is suspected that 1/100 teenagers in the US have POTS (5). Common forms of primary postural orthostatic tachycardia syndrome include partial dysautonomic POTS, immune mediated pathogenesis, adolescent, and hyperadrenergic state (3). Other people develop POTS secondary to another disorder like diabetes, amyloidosis, heavy metal poisoning, Sjogren syndrome, Ehlers-Danlos Syndrome, or paraneoplastic syndrome (3).
Developing POTS is a game changer for that person and their family. While it is an invisible illness to untrained professionals, the symptoms experienced by that individual can be life altering. A person with POTS uses three times more energy to stand than normal. Even minor movements around the house, including eating meals and showering, can be exhausting and increase symptoms (6). The quality of life of a person with POTS has been compared to those with congestive heart failure or chronic obstructive pulmonary disease (COPD; 7). POTS can truly be debilitating.
The long term outcome for someone with POTS depends on the underlying cause of this disorder. When people developed POTS as adolescents, 20% made a full recovery within 10 years, 60% had improved symptomology but still met the criteria for POTS, and the remaining 20% had maintained their level of symptomology or declined further since the time of diagnosis (8). Approximately 50% of people who develop POTS after a viral infection like mononucleosis or Lyme disease recover in two to five years (3) while those with the primary hyperadrenergic form will require lifelong treatment. For individuals with POTS secondary to another illness, treatment of the underlying disorder is critical in order to control or eliminate POTS symptoms (3)
4. Schondorf R, Low PA. Idiopathic postural tachycardia syndrome. Ann Neurol 1990; 28:271
5. Fischer, P. Postural orthostatic tachycardia syndrome. Mayo Clinic Podcast. 2007.
6. Grubb, BP, Kanjwal, Y, Kosinski, DJ. The postural tachycardia syndrome: A concise guide to diagnosis and management. J Cardiovasc Electrophysiol 2006; 17:108-112.
7. Benrud-Larson, LM, Dewar, MS, Sandroni, P, Rummans, TA, Haythornthwaite, JA, Low, PA. Quality of life in patients with postural tachycardia syndrome. Mayo Clinic Proceedings 2002; 77:531-537.
8. Kizilbash SJ, Ahrens SP, Bhatia R, Killian JM, Kimmes SA, Knoebel EE, Muppa P, Weaver AL, Fischer PR. Long-term outcomes of adolescent-onset postural orthostatic tachycardia syndrome. Presented at the 24th International Symposium on the Autonomic Nervous System, Kohala Coast, Hawaii, October 23, 2013.