Quantitative sensory testing predicts histological small fiber neuropathy in postural tachycardia syndrome
Sophia C.I. Billig, Joana C. Schauermann, Roman Rolke, István Katona, Jörg B. Schulz, Andrea Maier
Abstract
<h3>Background</h3> Retrospective investigation of the somatosensory profile and prediction of histologic small fiber neuropathy (SFN) in postural orthostatic tachycardia syndrome (POTS) was performed using quantitative sensory testing (QST) as a standardized noninvasive test. <h3>Methods</h3> In this investigation, full data sets from 30 patients (age: 34.03 ± 10.82 years, n = 6 males), including results of autonomic function testing, norepinephrine values, skin biopsy, and QST, were retrospectively analyzed. The QST data were compared with healthy controls (HCs) (age: 34.20 ± 10.5 years, n = 6 males, <i>t</i> test: 0.95). <h3>Results</h3> The evaluation of all QST parameters in POTS compared with HCs yielded differences in all thermal parameters (cold detection threshold: <i>p</i> < 0.05, warm detection threshold: <i>p</i> < 0.001, thermal sensory limen: <i>p</i> < 0.001, cold pain threshold: <i>p</i> < 0.05, and heat pain threshold: <i>p</i> < 0.001) and in paradoxical heat sensations (<i>p</i> < 0.05). Differences in nonpainful stimuli (mechanical detection threshold: <i>p</i> < 0.05 and vibration detection threshold: <i>p</i> < 0.001) were also detected. All patients who had clinical signs of SFN in combination with impairment of small fibers in QST also had SFN on skin biopsy. <h3>Conclusion</h3> These results suggest that a non–region-specific SFN in POTS compared with controls can be detected by noninvasive QST that predicts histologic small fiber pathology.