Chorea following SARS-CoV-2 infection and vaccination: a systematic review of reported cases.

Objectives: Chorea following SARS-CoV-2 infection and vaccination, has been increasingly recognized. We aimed to synthesize clinical and paraclinical characteristics, treatment responses, and outcomes of this neurologic complication.

Methods: We systematically reviewed LitCOVID, the World Health Organization database on COVID-19, and MedRxiv up to March 2023, following a published protocol.

Results: We included 14 chorea cases in patients with SARS-CoV-2 infection and eight following COVID-19 vaccination. Acute or subacute chorea preceded COVID-19 symptoms within 1-3 days or developed up to 3 months after infection. Frequently it was generalized (85.7%), with associated neurological manifestations (encephalopathy 35.7%; other movement disorders 7.1%). After vaccination, chorea had a sudden onset (87.5%) within 2 weeks (75%); 87.5% of cases presented hemichorea, with hemiballismus (37.5%) or other movement disorders; 12.5% presented additional neurological findings. Cerebrospinal fluid was normal in 50% of infected individuals but abnormal in all vaccinated cases. Brain magnetic resonance imaging detected normal basal ganglia in 51.7% of infection cases and 87.5% following vaccination.

Conclusion: In SARS-CoV-2 infection, chorea may present several pathogenic mechanisms: autoimmune response to infection, direct infection-related injury, or an infection-related complication (i.e., acute disseminated encephalomyelitis, cerebral venous sinus thrombosis, hyperglycemia); also, previous Sydenham chorea may relapse. After COVID-19 vaccination, chorea could be due to an autoimmune reaction or other mechanisms (vaccine-induced hyperglycemia, stroke).