Postural tachycardia syndrome (POTS) is a fairly common condition that may or may not be associated with autonomic neuropathy. In a retrospective analysis, we compared two groups of patients based on clinical and autonomic criteria, those with POTS in isolation (POTS-Alone), and POTS with evidence of autonomic neuropathy (POTS-AN). Of 260 records reviewed, 57 patients met the criteria for POTS; 38 (67%) patients assigned to the POTS-Alone group and 19 (33%) patients assigned to the POTS-AN group. A decreased sweat output on the quantitative sudomotor axon reflex test is the most frequent abnormal finding in the POST-AN group suggesting sympathetic cholinergic neuropathy. Clinically, headache and gastrointestinal symptoms were more frequent among the POTS-AN group. Therefore, POTS may exist in isolation and may differ from those associated with AN.
"Several lines of evidence point to a restricted peripheral neuropathy, specifically, sympathetic denervation predominantly in the lower hemibody, as a cause of POTS in some individuals. The evidence includes reports of venous denervation , impaired distal sudomotor function [4,5], lower norepinephrine spillover in the legs than the arms , and the association with denervation on skin biopsy . This condition is known as neuropathic POTS. "
[Show abstract][Hide abstract] ABSTRACT: To define the neuropathology, clinical phenotype, autonomic physiology and differentiating features in individuals with neuropathic and non-neuropathic postural tachycardia syndrome (POTS).
Twenty-four subjects with POTS and 10 healthy control subjects had skin biopsy analysis of intra-epidermal nerve fiber density (IENFD), quantitative sensory testing (QST) and autonomic testing. Subjects completed quality of life, fatigue and disability questionnaires. Subjects were divided into neuropathic and non-neuropathic POTS, defined by abnormal IENFD and abnormal small fiber and sudomotor function.
Nine of 24 subjects had neuropathic POTS and had significantly lower resting and tilted heart rates; reduced parasympathetic function; and lower phase 4 valsalva maneuver overshoot compared with those with non-neuropathic POTS (P<0.05). Neuropathic POTS subjects also had less anxiety and depression and greater overall self-perceived health-related quality of life scores than non-neuropathic POTS subjects. A sub-group of POTS patients (cholinergic POTS) had abnormal proximal sudomotor function and symptoms that suggest gastrointestinal and genitourinary parasympathetic nervous system dysfunction.
POTS subtypes may be distinguished using small fiber and autonomic structural and functional criteria. Patients with non-neuropathic POTS have greater anxiety, greater depression and lower health-related quality of life scores compared to those with neuropathic POTS. These findings suggest different pathophysiological processes underlie the postural tachycardia in neuropathic and non-neuropathic POTS patients. The findings have implications for the therapeutic interventions to treat this disorder.
PLoS ONE 12/2013; 8(12):e84716. DOI:10.1371/journal.pone.0084716 · 3.23 Impact Factor
"When Sandroni et al.  described the symptoms associated with POTS including dizziness, lightheadedness, and lower extremity weakness, they also reported frequent associated symptoms of dyspepsia, such as nausea, bloating, early satiety, and abdominal pain. In addition, patients with POTS who have an associated autonomic neuropathy harbor more gastrointestinal symptoms than those who do not . This association also holds true when explored from the reverse, gastrointestinal perspective. "
[Show abstract][Hide abstract] ABSTRACT: The pathophysiology of functional abdominal pain (FAP) is unknown. The upright portion of a tilt table test triggers typical symptoms in certain children.
To compare the pathophysiology and treatment response of children with FAP whose gastrointestinal symptoms (GI) were replicated (RGI) by tilt table testing (TTT) to those in whom TTT did not have this effect (NRGI).
An IRB-approved retrospective review of the autonomic laboratory database identified all children tested for GI complaints. We compared results of TTT, Valsalva maneuver, deep breathing and the axon reflex sweat test. Overall treatment response and that specific to fludrocortisone was ranked from 1 to 5, with 1 "much worse," 3 "neutral," and 5 "much better."
32/76 identified children had reproducible symptoms on TTT (RGI) and 44 did not (NRGI). The RGI group was younger, had a shorter duration of symptoms, more postural tachycardia syndrome (POTS) and benefited more from fludrocortisone (73% in RGI vs. 25% in NRGI).
Dividing patients with FAP according to the effect of TTT on their symptoms appears to delineate 2 fundamentally different groups, with potentially different pathophysiologies and treatment responses. A prospective study is needed.
Gastroenterology Research and Practice 02/2009; 2009(1):868496. DOI:10.1155/2009/868496 · 1.75 Impact Factor
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