Study of sympathetic skin response in patients with COVID-19 infection

Many articles hypothesized the potential role of autonomic nervous system in the pathogenesis and outcome of COVID-19 infection. Several studies reported both central and peripheral nervous system involvement in COVID-19 as well. Up to our knowledge, there is no study evaluating whether this virus could invade the autonomic nervous system affecting its function adversely. Sympathetic skin response (SSR) has long been used as a method of evaluating the autonomic nervous system. Regarding the importance of the autonomic nervous system in hemostasis and wide consequences of COVID-19 infection, we designed this study to evaluate the autonomic nervous system function in patients recovered from COVID-19 compared with normal population who are not yet infected by this virus by the means of SSR.

This case-control study included 70 patients surviving COVID-19 who met the inclusion and exclusion criteria that went under SSR. The data gathered were compared with those without the history of any symptoms attributable to COVID-19 during the pandemic.

There was a correlation between COVID-19 infection and abnormal SSR (p value < 0.0001) with the most effect on the latency prolongation of the action potential recorded from the median nerve at palms (effect size: right: 3.90, left: 3.69). Moreover, the greater severity of the disease correlated with more abnormality of parameters recorded by SSR technique.

Abnormal SSR parameters could be a good indicator of autonomic nervous system involvement in patients with COVID-19 infection. It might be a predictor of disease severity, clinical outcomes and prognosis as well.