, a multinational team of researchers reported at the International Congress of Parkinson’s Disease and Movement Disorders.
SARS-CoV-2 led to numerous discussions about a potential post–COVID-19 emergence of new-onset parkinsonism in susceptible individuals, often referred to in the literature as a “perfect storm” or a “wave” of parkinsonism, according to lead study author Iro Boura, MD.
Postviral precedence
“Although pathogens have been associated both with parkinsonism cases and Parkinson’s disease pathogenesis, the main concern of a potential connection between COVID-19 and new-onset parkinsonism arose from the historically documented parkinsonism cases appearing with encephalitis lethargica,” said Dr. Boura, a PhD candidate with the University of Crete in Greece and ex-fellow at King’s College London.
Dr. Iro Boura
Encephalitis lethargica appeared between 1916 and 1930 and has been epidemiologically related to the Spanish influenza pandemic, “although this link has been strongly debated by other researchers,” she added.
Because the connection of COVID-19 and parkinsonism seemed highly speculative, Dr. Boura and movement disorder specialist Kallol Ray Chaudhuri DSc, FRCP, MD, decided to search for any data supporting this notion. “Such a possibility would have a significant impact on everyday practice, including long follow-up neurological assessments of COVID-19 patients, along with greater vigilance in recognizing potential symptoms,” said Dr. Boura.
They found no organized research exploring this link, aside from published case reports.
Scant evidence of a parkinsonism wave
The investigators conducted a review of the literature up to February 2022 to identify and analyze published cases of new-onset parkinsonism following a confirmed SARS-CoV-2 infection in otherwise healthy individuals. They ended up with 20 such cases.
Although some cases presented during or shortly after a COVID-19 infection, “the numbers are currently quite low to draw safe conclusions and generalize these findings as a risk of parkinsonism for the general population,” said Dr. Boura. Overall, parkinsonism appeared in the context of encephalopathy in 11 patients. Four patients developed postinfectious parkinsonism without encephalopathy. Another four had phenotypic similarities to idiopathic Parkinson’s disease.
Nine patients were responsive to levodopa, while four required immunomodulatory treatment.
Although cases have already been reported, current data do not yet justify the concept of a post–COVID-19 parkinsonism wave. However, long-term surveillance is crucial to ensure that reports of further cases are carefully documented and analyzed.
Dr. Chaudhuri’s research team recently wrote a book exploring the numerous aspects of COVID-19 and parkinsonism, including Parkinson’s disease, said Dr. Boura.
“Moreover, the COVID-19 Clinical Neuroscience Study (COVID-CNS), with serial follow-up visits for COVID-19 patients, including imaging, is currently running in the United Kingdom with the active participation of Prof Chaudhuri’s team, aiming at revealing any potential parkinsonism cases after a COVID-19 infection,” she said.