POTS Variaty

[Guest veryblue]

Hi I was just wondering if anyone knows anything about the different varities of POTS.

hyperadrenergic

partial dysautonomia

brain stem dysregulation

How can you be sure what kind you have?

Does anyone know what kind you have?

[Jackie]

Best answer - 1. don't know and 2. would like to

[MightyMouse]

this article might help a bit...

http://www.annals.org/cgi/content/full/137/9/753

and from the main sections of the DINET site under "mehcanisms":

"Brain-stem dysregulation may be occurring in some POTS patients (Novak, Novak, Opfer-Gehrking, O'Brien & Low, 1998). Researchers have identified a subset of patients with marked orthostatic hypertension, markedly labile blood pressure and troublesome orthostatic symptoms (Low, Schondorf, Novak, Sandroni, Opfer-Gehrking & Novak, 1997, pp. 686-687). These patients present as though they are suffering from baroreflex failure, although the baroreflexes are working. Excessive sympathetic activity is noted, which suggests the possibility of central (presumably brain-stem) dysregulation. One patient reportedly improved after microvascular decompression at the region of the left medulla (Low et al., 1997, p. 687)."

"Reduced cerebral blood flow is occurring in some POTS patients. A reduction of cardiac output by arrhythmias, bradycardia, or intrinsic cardiac causes of pump failure can cause fainting, or other clinical manifestations of reduced cerebral blood flow (Streeten, 1999). Blood pooling in the lower body may also cause reduced blood flow to the brain. It has been reported that a person with POTS can have a 28% decrease in brain blood flow upon standing (Robertson, 2000). A normal person will have about a 9% decrease in blood flow to the brain upon standing. Transcranial Doppler ultrasonography is useful in detecting a reduction in cerebral blood flow (Fredman, Biermann, Patel, Uppstrom & Auer, 1995). Orthostatic symptoms have been attributed to impaired cerebral perfusion, even in the absence of a significant fall in blood pressure (Jacob & Biaggioni, 1999). "

"Central nervous system abnormalities may be occurring in patients with reduced cerebral blood flow (Hermosillo, Jauregui-Renaud, Kostine, Marquez, Lara & Cardenas, 2002). One study reported that continuous observation of the Doppler recording in patients with postural tachycardia showed intermittent fluctuation of the cerebral blood flow velocity, with an oscillatory pattern (Hermosillo et al., 2002). This fluctuation in cerebral blood flow velocity occurred in spite of there being no systemic hypotension. This study also showed that when compared with neurocardiogenic syncope patients, those with postural tachycardia had larger variations of the pulsatility index (systolic velocity-diastolic velocity/mean velocity). The results suggest that patients with postural tachycardia, on standing up, could have an inefficient regulation of cerebral blood vessels (Hermosillo, et al., 2002). These findings led the researchers to conclude that central nervous system abnormalities may play a pivotal role in the pathogenesis of postural tachycardia syndrome (Hermosillo, et al., 2002)."

"Hyperdopaminergic states may be the underlying problem for some people with orthostatic intolerance. Some patients have been found to have a significant increase in upright (free + sulfconjugated) dopamine levels (Kuchel, Buu, Hamet, Larochelle, Gutkowska, Schiffrin, Bourque & Genest, 1985). Free plasma norepinephrine also tends to be higher in these patients. The excessive dopamine release might be causing natriuresis and vasodilatation, thus contributing to the pathophysiology of this disorder (Jacob & Biaggioni, 1999)."

Partial dysautonomia...also from the main DINET site, under "POTS overview":

Those said to have partial dysautonomia have a system trying to compensate for a lack of venous constriction through excessive catecholamine output (Grubb. 2000)."

Nina