Covid-19 related ataxia and myoclonus: Para- or post-infectious disorder?

Since the onset COVID-19 pandemic, several post-infectious neurological disorders have been reported, among which at least ten cases showed movement disorders consisting of tremor, myoclonus, ataxia. We report a case series of three patients who developed these symptoms after the SARS-CoV-2 infection. Patients’ data were collected from medical records during COVID 19 pandemic. Diagnosis of COVID-19 was supported by RT-PCR on nasopharyngeal swab. Three male patients (mean age 63 years) developed generalized myoclonus and ataxia. In two patients the disorder appeared 30 and 24 days after the onset of the SARS-CoV-2 infection, respectively, while in the other case the neurological symptoms began at the same time. The clinical pictures showed a rapidly worsening course. Brain MRI did not reveal abnormalities in any patients at the disease onset. On day 70 the imaging control showed mild cerebellar atrophy in one patient. A brainrF-FDG-PET scan disclosed a bilateral fronto-mesial hypometabolic pattern in one patient. RT-PCR for SARS-CoV-2 in CSF, tested in two cases, resulted negative. EEG and ENG did not reveal relevant abnormalities, as well as CSF analysis, including immunoblot. Two patients were treated with intravenous immunoglobulin infusion (IVIg) and one patient with plasmapheresis (PEX). They subsequently improved during the course of few weeks. Myoclonus and ataxia possibly occur as COVID 19 postinfectious as well as parainfectious immune-mediated disorder. Indeed, IVIG or PEX were effective in all three patients. This kind of disorders have been described as postinfectious events, in contrast, we report, to our knowledge, the first parainfectious case.