Recent publications have indicated that people with PD are not at increased risk of the complications of COVID-19 compared with others of the same age (1-3). Advanced age itself seems to be a risk factor for severe disease. However, this week a paper was accepted for publication in the journal Movement Disorders which reports that people who have had PD for an average of 12 years or more may be more likely to become seriously ill or die after catching SARS-CoV-2 virus that causes COVID-19 (4). The statement is based on a small case series of 10 people with PD, average age 78. The report was written in collaboration with two European academic movement disorders centers.
The Parkinson and Movement Disorders Unit in Padua, Italy reports a catchment of 1022 patients with PD from the province, which also had 3407 cases of COVID-19 in the general population. Among the infected were two women with advanced PD, both nursing home residents. One of the women was asymptomatic aside from a limited fever, and the other died from respiratory complications of COVID-19.
The Parkinson’s Foundation Centre of Excellence at King’s College Hospital in London, UK has a catchment of 4000 PD patients, and reported eight cases of COVID-19 among that cohort: six men and two women, all with advanced disease. Most of these patients required additional levodopa while sick with COVID-19. Anxiety, orthostatic hypotension, cognitive impairment, and psychosis worsened during the infection. Fatigue was the dominant complaint. Three of these patients died from COVID-19 pneumonia.
The authors noted that people with advanced therapies such as infusions of levodopa (the dopamine pump), or deep brain stimulation seemed to be high risk. The risk among people with advanced disease likely relates to worse overall health condition in people who have advanced in both disease and age. In advanced PD muscles are susceptible to rigidity (stiffness) and this can include the ones associated with breathing. At baseline some patients have trouble clearing secretions, trouble coughing, an impaired cough reflex, or shortness of breath. When regular exercise is halted, these issues may worsen, making one less able to fight off COVID-19.
SARS-CoV-2 is a member the coronavirus family. In 1992 it was shown that some people with PD had antibodies to much more benign strains of coronavirus in the cerebrospinal fluid (CSF) (5), which raised the question of whether an infection might trigger or cause PD. Some researchers have questioned whether coronaviruses might infect cells high in the nasal passage, cause the loss of the sense of smell (anosmia), and then enter the brain. SARS-CoV-2 binds to angiotensin-converting enzyme 2 (ACE2) receptors, which are present on dopamine neurons, and are reduced significantly in PD. There has been no evidence to date of direct infection of the brain of PD patients.
Please take precautions and avoid infection. I think the preceding paragraph is interesting, but far from anything more than associations. And, we should be careful not to draw strong conclusions on the basis of such a small case series. It seems more likely that those who have poor health (including advanced PD) generally are at higher risk of complications of COVID-19, rather than some facet of PD that makes COVID-19 more dangerous. I will monitor for any more reports of COVID-19 in the PD population worldwide.
REFERENCES
- Helmich RC, Bloem BR. The Impact of the COVID-19 Pandemic on Parkinson’s Disease: Hidden Sorrows and Emerging Opportunities. J Parkinsons Dis. 2020;10(2):351-354.
- Stoess, et al. Editorial: MOVEMENT DISORDERS IN THE WORLD OF COVID-19. Mov Disord. 2020.
- Papa, et al. Impact of the COVID-19 pandemic on Parkinson’s disease and movement disorders. Mov Disord. 2020
- Antonini, et al., Outcome of Parkinson’s Disease patients affected by COVID-19. Mov Disord. 2020, doi: 10.1002/mds.28104
- Fazzini E, Fleming J, Fahn S. Cerebrospinal fluid antibodies to coronavirus in patients with Parkinson’s disease. Move Disord 1992;7(2):153-158
