"What oxygen is to the lungs, such is hope to the meaning of life" ~Emil Brunner
Postural Orthostatic Tachycardia Syndrome (P.O.T.S.) was first named and identified by Schondorf and Low in 1993, however the syndrome has been described in medical studies dating back to at least 1940. Hypotension associated with POTS has been previously described as the "neurally mediated hypotension" form of POTS. Postural tachycardia syndrome or more commonly known, as P.O.T.S. is a rare disorder that is characterized by the body's inability to make the necessary adjustments to counteract gravity when standing up. The defining symptom of POTS is an excessive heart rate increment upon standing. The hallmark symptom of POTS is an increase in heart rate from the supine to upright position of more than 30 beats per minute or to a heart rate greater than 120 beats per minute within 10 minutes of head-up tilt. This tachycardic response is often accompanied by a profound decrease in blood pressure and a wide variety of symptoms associated with hypotension including:
Inappropriate levels of epinephrine and norepinephrine lead to anxiety-like symptoms:
Symptoms present in various degrees of severity depending on the patient. POTS is a serious, though non-life threatening, medical condition that can be severely disabling and debilitating. Some patients are unable to attend school or work, and especially severe cases can completely incapacitate the patient.
The causes of POTS are not fully known. Most patients develop symptoms in their teenage years during a period of rapid growth and see gradual improvement into their mid-twenties. Others develop POTS after a viral or bacterial infection such as mononucleosis or pneumonia. Some patients develop symptoms after experiencing some sort of trauma such as a car accident or injury. Women can also develop POTS during or after pregnancy. These patients generally have a poorer prognosis. In one large test, 12.5% of 152 patients with POTS reported a family history of orthostatic intolerance, suggesting that there is a genetic inheritance associated with POTS. So far no one has provided an explanation for POTS which is applicable to all sufferers, however there are many theories; Alpha-receptor dysfunction may be occurring in some POTS patients. Alpha-1 receptors cause peripheral vasoconstriction when stimulated. Alpha-1 receptor super sensitivity may be causing dysautonomia in some patients. Beta-receptor super sensitivity may occur with hyperadrenergic states in some people with POTS. Some patients have been found to have a significant increase in upright dopamine levels. Free plasma norepinephrine also tends to be higher in these patients. Reduced venous return is one of the main mechanisms that causes POTS symptoms. Venous return can be reduced due to conditions such as low plasma volume (hypovolemia), venous pooling and denervation. A hyperadrenergic state may result as the body attempts to compensate for these abnormalities. Sympathetic Overactivity is observed in many POTS patients. The sympathetic overactivity can be secondary to a number of factors, some of which may be peripheral denervation, venous pooling, or end-organ dysfunction.
Diagnosis--POTS can be difficult to diagnose. A routine physical examination and standard blood tests will not indicate POTS. A tilt table test is vital to diagnosing POTS, although all symptoms must be considered before a final diagnosis is made. Tests to rule out Addison's Disease, pheochromocytoma, electrolyte imbalance, Lyme Disease, Celiac Disease, and various food allergies are usually performed. A blood test may be performed to verify abnormally high levels of norepinephrine present in some POTS patients. Between 75 and 80 percent of POTS patients are female and of the menstruating age. Most male patients develop POTS in their early to mid-teens during a growth spurt or following a viral or bacterial infection. Some women also develop POTS symptoms during or after pregnancy.
This website/blog provides general information and is not a substitute for professional medical advice. The author is not responsible or liable for any diagnosis or action made by a user based on the content of this website. The author is not liable for the contents of any external websites listed. Consult your physician if you are in any way concerned about your health. In an emergency go directly to the ER or call 911(USA). Other emergency numbers for other countries can be found here
***Information and credit goes to these websites for P.O.T.S. information
Last updated_ March 1,2013