Coronavirus Disease 2019 and Related Parkinsonism: The Clinical Evidence Thus Far.

ABSTRACT

Background: The Coronavirus disease 2019 (Covid-19) pandemic has fueled both research and speculation, as to whether it could be a "perfect storm" for a post-Covid emergence of parkinsonism in some susceptible individuals, analogous to the post-encephalitic parkinsonism reported after the 1918 influenza epidemic. This theory is further augmented by reports of a pathogenic effect of the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) on the central nervous system with specific impact on the dopaminergic pathway, as well as the possibility of the virus to selectively bind to Angiotensin-Converting Enzyme-2 (ACE-2); these molecules are expressed abundantly in the midbrain dopamine neurons and, are likely involved in several cellular mechanisms cited in Parkinson's Disease (PD) pathophysiology. Objectives­Methods: Therefore, we performed a review of the literature up to February 2022 to explore the current landscape considering published cases of new-onset parkinsonism after a SARS-CoV-2 infection in otherwise healthy individuals. We summarized their clinical features, diagnostic and treatment approaches, discussing potential underlying mechanisms in light of PD pathogenesis theories. Results: Twenty cases that developed parkinsonian features simultaneously or shortly after a reported SARS-CoV-2 infection were reviewed. In 11 of them, parkinsonism appeared in the context of encephalopathy, while four patients developed post-infectious parkinsonism without encephalopathy, and four bore similarities to idiopathic PD. Nine patients exhibited a good response to dopaminergic therapy, while four responded to immunomodulatory treatment. Conclusions: Available data does not yet justify a clear association between the Covid-19 pandemic and a parkinsonism wave. However, vigilance is necessary, as long-term effects might have not been revealed.