The Pathophysiology of Neuropathic and Non-Neuropathic Postural Tachycardia Syndrome (P05.203)

Abstract

OBJECTIVE: To define the clinical characteristics, fatigue severity, autonomic function and differentiating features in individuals with neuropathic and non-neuropathic POTS. BACKGROUND: The postural tachycardia syndrome (POTS) is defined as an exaggerated heart rate in the upright position with symptoms of orthostatic intolerance. Some patients with POTS have an underlying small fiber neuropathy. DESIGN/METHODS: Twenty-four subjects with POTS and 10 healthy controls 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 categorized as neuropathic and non-neuropathic POTS, based on abnormal IENFD and/or heat and heat-pain detection thresholds. Differences in autonomic function and symptom questionnaires were analyzed by ANOVA with corrections for multiple analyses. Significance was set at P RESULTS: POTS subjects had greater fatigue, anxiety, physical impairment, orthostatic intolerance and perceived disability than controls (P CONCLUSIONS: Small fiber sensory neuropathy measures may be used to differentiate POTS subtypes. Individuals with non-neuropathic POTS have greater anxiety, orthostatic intolerance and perceived disability despite better overall autonomic function than those with neuropathic POTS. These findings suggest that different pathophysiological mechanisms that underlie the postural tachycardia in neuropathic and non-neuropathic POTS. These findings may have implications for therapeutic interventions to treat this disorder. Supported by: NIH NINDS K23NS050209 (CHG) and NIH RO1 HL059459 (RF). Disclosure: Dr. Gibbons has nothing to disclose. Dr. Bonyhay has nothing to disclose. Dr. Benson has nothing to disclose. Dr. Freeman has received personal compensation for activities with Pfizer, Abbott, Depomed, Johnson & Johnson, Sanofi, and Chelsea Pharmaceuticals. Dr. Freeman has received personal compensation in an editorical capacity for Autonomic Neuroscience - Basic and Clinical and Clinical Journal of Pain.