The Influence of Coronavirus Disease-2019 (COVID-19) On Parkinson’s Disease: An Updated Systematic Review

Abstract

Background: The novel Coronavirus (COVID 19) infection has affected the population with various medical issues including the underlying neurological comorbidities such as Parkinson disease. COVID 19 is found to bind with the host angiotensin-converting enzyme 2 (ACE2) receptors for viral entry. ACE2 receptors are normally expressed in various body surfaces as well as in the neurons and glial cells where they act as an entry port to SARS-CoV-2 infection to invade the central nervous system (CNS). ACE2 are also highly expressed in dopamine neurons which might worsen the outcome in terms of motor symptoms in PD with the treatment course. It may lead to an indirect response via immune-mediated cytokine storms and propagate through CNS leading to damage. Parkinsons disease has also been noticed due to certain post viral infections apart from COVID-19 such as, HSV, Influenza virus A, Measles virus, Cytomegalovirus and Mumps (Olsen et al, 2018). We aim to provide a thorough review on neurological outcomes and impact of COVID-19 in Parkinson disease. Methods: A systematic review was conducted to analyze the impact of COVID 19 in patients with Parkinson disease (> 21 yo). Systematic literature search was done using PubMed, Science Direct, Google Scholar and Cochrane databases. PRISMA guidelines were followed summarized in Fig. 3 for study acquisition. Results: Of the Parkinsons patients that were tested positive for SARS-CoV 2, worsening of motor symptoms were reported along with other COVID 19 symptoms (Fig. 4 and 5). These symptoms include bradykinesia, tremors, gait disturbances, delirium and dementia and severe spasms of arms and legs. Encephalopathy was also one of the main symptoms presented in two of the studies. Increased mortality rates were identified for those who were hospitalized due to COVID-19 and PD when compared to other patients. Conclusion: Parkinsons disease may experience substantial worsening of motor and non motor symptoms during COVID 19. Due to the novelty of the virus, studies were reported from recent years and further extensive studies are needed to explore more about the disease severity and neurological outcomes when compared to other non-PD patients. Authors identify this as a limitation for this paper. Additional studies are needed to understand the role of ACE2 in increasing vulnerability to viruses and role of ACE inhibitors as treatment modality.