Generalized myoclonus in COVID-19

Objective To report 3 patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) who developed generalized myoclonus. Methods Patient data were obtained from medical records from the University Hospital "12 de Octubre," Madrid, Spain. Results Three patients (2 men and 1 woman, aged 63-88 years) presented with mild hypersomnia and generalized myoclonus following the onset of the so-called inflammatory phase of coronavirus disease 2019 (COVID-19). All of them had presented previously with anosmia. Myoclonus was generalized with both positive and negative jerks, predominantly involving the facial, trapezius, sternocleidomastoid, and upper extremities muscles. These myoclonic jerks occurred spontaneously and were extremely sensitive to multisensory stimuli (auditive and tactile) or voluntary movements, with an exaggerated startle response. Other causes of myoclonus were ruled out, and none of the patients had undergone respiratory arrest or significant prolonged hypoxia. All of them improved, at least partially, with immunotherapy. Conclusions Our 3 cases highlight the occurrence of myoclonus during the COVID-19 pandemic as a post- or para-infectious immune-mediated disorder. However, we cannot rule out that SARS-CoV-2 may spread transneuronally to first- and second-order structures connected with the olfactory bulb. Further investigation is required to clarify the full clinical spectrum of neurologic symptoms and optimal treatment.