Coronavirus and nervous system: What is the relationship?

Background and aims: Coronavirus disease 2019 (COVID-19) was thought to cause a respiratory disease, sparing the other organs such as the nervous system. However, many patients developed a variety of symptoms suggesting the neurotropism of the virus. Methods: Patients diagnosed with COVID-19 who developed neurological symptoms during the infection or afterwards were included in our study. Results: Case1: A 52-year-old female presenting protein S deficiency and superficial venous thrombosis developed motor deficit and a confusional state. Her brain MRI showed multiple ischemic strokes. Case2: A 35-year-old man with familial history of epilepsy and psychomotor retardation, with personal history of pulmonary tuberculosis, glue sniffing and ethylism was admitted for psychiatric symptoms followed by tetraparesis. His brain MRI showed confluent hyperintensities of white matter and his electromyogram revealed a demyelinating polyneuropathy. Case3: A 69-year-old man admitted for multiple cerebral hematomas with altered state of consciousness and respiratory depression probably worsened by the infection Case4: A 32-year-old man developed three weeks after COVID-19 infection a seizure in context of apyrexia. His brain MRI was normal, his electroencephalogram showed a bifrontal slowdown activity. Conclusion: Different mechanisms are thought to explain neurological manifestations in COVID-19 infection. Direct involvement of the nasal epithelium is responsible for the largely described anosmia. Ischemic stroke is related to the hypercoagulability and cardio-embolic complications. Confusional state is not related with infectious encephalopathy as suspected but to the influence of hypoxia, endothelial dysfunction and microthrombi. Peripheral nervous system involvement is less reported but many cases of Guillain Barre syndrome and myositis were reported.