As we learn more about the consequences of COVID-19, it becomes clear that infection can lead to diseases and conditions that affect various organs, including the brain. But do neurological and cerebrovascular conditions occur at higher rates in people who have COVID-19 compared to those who suffer from a flu attack or bacterial pneumonia? A team of scientists conducted an observational study to find out.
The study, recently published in Frontiers in Neurology and presented at the 8th Congress of the European Academy of Neurology, was conducted by a team based at Copenhagen University Hospital and the University of Copenhagen in Denmark. Examining the electronic health records of more than 919,000 people who had been tested for COVID-19, as well as those diagnosed with influenza or pneumonia, the scientists were able to calculate the frequency of Alzheimer’s disease, the Parkinson’s disease, ischemic stroke and intracerebral disease. hemorrhage in these different cohorts.
People who tested positive for COVID-19 experienced Alzheimer’s disease 3.5 times more often (RR = 3.5; 95% CI: 2.2-5.5) than people who were negative for COVID. Parkinson’s disease was diagnosed 2.2 times more frequently (RR = 2.6; 95% CI: 1.7-4.0); ischemic stroke 2.7 times more frequent, (RR = 2.7; 95% CI: 2.3-3.2); and intracerebral hemorrhage 4.8 times more frequent (RR = 4.8; 95% CI: 1-8-12.9).
However, compared to people who had been diagnosed with influenza or bacterial pneumonia, COVID-positive patients did not experience neurological disorders more frequently, with the exception of ischemic stroke. Among the 8,013 people who tested positive for COVID-19, the risk of stroke was increased compared to those who had the flu (RR = 1.7; 95% CI: 1.2-2.4) or pneumonia bacterial (RR = 2.7; 95% CI: 1.2). -6.2).
This higher stroke rate may be because COVID-19 is known to induce a particularly aggressive inflammatory response in the body, the study authors say. “An unintended consequence of this inflammatory response is a hypercoagulable state, which increases the risk of thromboembolism and therefore ischemic stroke,” Pardis Zarifkar, MD, a neurologist at Copenhagen University Hospital, told Contagion. author of the study. “By nature, some microorganisms elicit stronger immune responses than other microorganisms.”
The risk of stroke increased especially in middle-aged patients with COVID-19, but Zarifkar and colleagues acknowledge that because the main risk factor for stroke is age, and older patients usually have comorbidities leading to poorer COVID-19 outcomes in general, the stroke rate in middle-aged people with COVID-19 may appear more pronounced compared.
Although Alzheimer’s and Parkinson’s disease cause physiological changes years before symptoms occur, being infected with COVID-19 and / or being hospitalized can lead to physical impairment that allows for an early diagnosis of these neurological conditions. Simply monitoring patients closely can also allow doctors to discern neurological problems. “[W]Biological mechanisms may explain a subsection of the increases, hopefully a decompensation of symptoms after infection and the focus of scientific communities on COVID-19 survivors may have led to an early diagnosis of diseases that are already in process. said Zarifkar.
COVID-19 causes long-term symptoms of COVID, which can include brain fog and fatigue, in a significant percentage of patients; therefore, Zarifkar and his team are currently conducting clinical trials that are expected to allow for a deeper understanding of cognitive impairment and mental health challenges in people hospitalized for conditions that include, among others, COVID-19 .