TH-285. Autonomic nervous system dysfunction in long-COVID patients

ABSTRACT

Introduction: Accumulating evidence supports that 6 months after COVID-19 almost 80% of the patients present residual neurological manifestations. Some of these symptoms may be associated with autonomic nervous system (ANS) damage. Several possible mechanisms have been proposed, including the detrimental effect of the virus-induced cytokine storm, direct viral spread into the nervous system, and an immune-mediated autoimmune mechanism. The extent of ANS involvement and exact pathological locations are unknown. Method(s) The aim of our study was to characterize the peripheral autonomic nervous system involvement in post-COVID patients. We compared the outcomes of neurological and neurophysiological examinations with the results of asymptomatic control subjects. In our study, we studied 33 patients (20 women, mean age 39 +/- 8 years) with post-COVID, transient or persistent neurocognitive and/or autonomic nervous system symptoms and 8 (4 women, 29 +/- 5 years) control subjects. After detailed neurological examination, the ANS functional assessment was performed with Quantitative Sudomotor Axon Reflex Test (QSART) and Sudomotor Sympathetic Skin Response (SSR) using Vitalscan SudoCheck + machine. Heart rate variability (HRV) was determined using a WIWE instrument. Result(s) Focal neurological signs were not found in any of the patients. Regarding the autonomic nervous system studies, SSR measurement was the most sensitive in our population we found abnormal SSR values in 8/33 of our post-COVID patient group (24%), while we did not find any abnormal SSR values in the control group. These 8 post-COVID patients showed moderate to severe (bioelectrical skin conductivity 24.3-59.4 microS) ANS dysfunction. During the one-minute HRV measurement, we assessed the standard deviation of heart rate variability (SDNN) and the root mean square of the RR intervals (RMSSD). Abnormally low values were measured in 14/33 patients (42%) (SDNN mean 18-23 ms, RMSSD mean 13-14 ms). Conclusion(s) In our study, different neurophysiological examination modalities confirmed ANS involvement in post-COVID patients. The extent of cardiovascular autonomic involvement (42%) was higher than sudomotor dysfunction (24%). These ratios significantly exceed the results of similar measurements in the age-matched control group. We suggest that the dysautonomia profile might explain the persistent symptoms after COVID-19. Copyright © 2022