Asymptomatic peripheral neuropathy in patients with SARS-CoV-2 infection

Background and aims: Several neurological complications related to SARS-CoV-2 infection have been reported. The involvement of peripheral nervous system (PNS) consists in the development of immune-mediated neuropathies such as Guillain-Barre Syndrome. In this study we aim at assessing the presence of asymptomatic abnormalities in peripheral nerves conduction during the acute phase of COVID-19 and, their correlation with blood circulating inflammatory markers. Methods: Thirty-nine patients with COVID-19 were assessed by electroneurographic study of lower limbs and blood tests within one week of hospital admission (T0) and after 30 ± 10 days (T1). Results: Electroneurographic changes were found at least on one nerve at T0 in 12 patients, consisting of axonal or demyelinating changes. Two biological markers were found to be significantly correlated with the presence of neuropathic changes: Reactive Protein C and lymphocyte count. Patients with pathological electrophysiology at T0 showed significant improvement of electrophysiological parameters at T1. The improvements in electroneurographic data were significantly correlated with the trend of laboratory parameters, in particular with fibrinogen, D-Dimer, ferritin, C Reactive protein and lymphocytes. None of the patients with neuropathic changes developed clinical evidence of a full-blown peripheral neuropathy over time. Conclusions: Our study shows that asymptomatic alterations of the PNS can be found during the acute phase of COVID-19. These alterations significantly improve after 20–40 days from the acute phase of infection and that the improvement correlates significantly with the trend of laboratory parameters. Further studies are needed to evaluate possible long-term neurological complications and the predictive value of subclinical damage of PNS in the acute phase of infection.