A previously healthy 42-year-old man presented with difficulty speaking, cognitive deficits, ataxia, and progressive disabling jerks in upper and lower limbs, leading to falls (see Supplementary video-). Neurological examination demonstrated spontaneous, action-induced, and tactile-sensitive myoclonus on the face, upper extremities, and lower extremities. He had dysmetria and dysdiadochokinesia with superimposed action-induced myoclonus in the upper and lower extremities. Myoclonus prevented him from standing independently, and he had a wide-based gait. The rest of the neurological examination was normal. Laboratory tests including renal function, liver function, ammonium, urea, and CO2 were normal, except for the nasopharyngeal RT-PCR test for SARS-CoV-2, which was positive. Computed tomography (CT) of the head and brain magnetic resonance imaging (MRI) were normal. Electroencephalogram (EEG) and electromyography (EMG) were performed but did not reveal any abnormalities. Given these findings and the positive SARS-CoV-2 PCR, myoclonus was considered postinfectious. No other symptoms such as fever, myalgia, cough, fatigue, hyposmia, or hypogeusia were present. Cerebrospinal fluid (CSF) analysis was unremarkable, RT-PCR test for SARS-CoV-2 and autoantibodies were negative. He was treated with methylprednisolone 1000 mg IV daily for five days, bringing about a partial resolution of myoclonus. Complete recovery was observed on a follow-up session one month later.
A 38-year-old man was referred to our clinic with generalized jerks in his hands (see Supplementary video-). A week before, he had been discharged from the hospital after four days of hospitalization due to a positive nasopharyngeal RT-PCR test and evident involvement of his lungs. Four days after discharge, he developed fine jerks in his hands and could not write; three days later, he was referred to our clinic with progression and generalization of jerks. He had generalized myoclonus in upper and lower limbs and bizarre abnormal movements that diminished with distraction; he was also restless and seemed anxious. The rest of the neurological examinations were normal. Lab tests were unremarkable. Laboratory investigations and brain MRI scans were normal. CSF analyses, including cell count, protein, and autoimmune panel, were normal. Clonazepam (2 mg/day), levetiracetam (1000 mg/day), and IV methylprednisolone for 5 days (1 g/day) were started, resulting in partial improvement. After two weeks, myoclonus was resolved; functional movements improved with some residual deficits, but he was still suffering from anxiety.