Post-coronavirus inflammatory cerebral peduncle lesion presenting as painful tonic spasms

Painful tonic spasms (PTS) are paroxysmal, stereotyped, painful episodes of involuntary posturing typically associated with demyelinating or structural lesions within the corticospinal tract. We report a case of PTS in temporal association with a COVID-19 infection, most likely attributable to post-infectious neuroinflammation. A woman in her 40s developed frequent, disabling, painful spasms of the left extremities 2 weeks after a COVID-19 infection. An MRI of the brain revealed a solitary contrast-enhancing T2/fluid-attenuated inversion recovery hyperintense ovoid lesion in the right cerebral peduncle. Comprehensive cerebrospinal fluid and serum evaluation, including demyelinating and autoimmune panels, was unremarkable. A 24-hour electroencephalogram capturing three episodes showed no electrographic abnormalities. Symptoms resolved following a short course of high-dose intravenous methylprednisolone and long-term oxcarbazepine. Serial imaging over 2 years demonstrated an interval decrease in lesion size and complete resolution of contrast enhancement, most consistent with a monophasic post-infectious inflammatory aetiology.