Your Brain On Coronavirus
A guide to the curious and troubling impact of the pandemic and isolation
The coronavirus pandemic frustrates and confounds epidemiologists and immunologists, even after months of study. It frustrates politicians and public health officials dealing with mask non-compliance. It frustrates everyone stuck at home, whether they lost their job or adapting to Zoom.
After exposure to the virus, it first enters the lungs, using host machinery to replicate. The virus itself is just a genetic sequence enclosed in a protein and lipid coat. It binds the ACE2 receptors on lung cells, with a spike protein located on its protein-lipid coat. This receptor, attached to the virus, trafficks into the lung cell. Here the virus hijacks the machinery of the cell to replicate, damaging lung tissue and spreading throughout the body.
The ACE2 receptor, expressed in many regions of the body, is vulnerable to further entry of these viral particles. The ACE2 receptor regulates blood pressure, nutrient absorption and inflammation. These pathways converge and mediate brain health and disease.
The novel coronavirus perplexed us for many different reasons. A large majority of people who get it don’t display any symptoms, while some display symptoms for many months and others require ventilators to breathe. It is unclear whether someone infected with coronavirus retains long-term immunity.
Also, troubling findings implicate this disease in the induction of stroke and the worsening of mental health. The realization that there are likely long-term complications of coronavirus infection is worrying, as millions of people may require expensive coverage for this new pre-existing condition.
Those of us lucky to avoid being infected become more socially isolated and lonely. Many studies report the worsening of mental health symptoms, especially in frontline workers, nurses and doctors. These professionals are more prone to burning out and require extra care.
COVID-19 and Stroke
The cells in the brain require a disproportionate amount of energy to function. When deprived of oxygen, even for minutes, the cells begin to die, leading to a variety of debilitating sensory, motor or language deficits depending. When there is blood loss to a specific region of the brain, cells cannot use oxygen to generate energy. If there is a clot in an artery, fresh oxygen cannot travel to any regions primarily supplied by that blood vessel. These events, classified as ischemic strokes, cause lifelong disability in some of those afflicted.
Early findings in patients found abnormal clotting in blood vessels. Vessels around the lungs or even arterial blood-flow to the brain is interrupted. Thus, individuals infected with coronavirus who suffered abnormal blood clotting as a result, were at higher risk of stroke.
In June of 2020, researchers published a report of neurological symptoms in the New England Journal of Medicine. While they did not report common symptoms of having a stroke, they showed other strange brain-related features. Of thirteen COVID-19 patients who underwent brain imaging, three of them showed signs of an ischemic stroke. A subset of eight of these patients showed other types of inflammation, while eleven presented with a lack of blood flow to the frontal areas of the brain.
Though a preliminary observational study, it suggested that the coronavirus impacted blood clotting and flow to the brain. Several studies since identified swathes of patients suffering from ischemic strokes or brain/vascular inflammation. Another study reviewed the current state of evidence, concluding that 41% of patients suffering from neurological symptoms after COVID-19 infection, suffered from strokes. Larger studies however, are needed to decipher how common this is among all those infected with the novel coronavirus.
Depending on which region of the brain loses oxygen, stroke may manifest as a broad range of symptoms. If cells die in an area of the brain responsible for motor movement, it later manifests in unilateral or bilateral difficulties with movement. Other common symptoms involve fatigue, challenges with balance or walking, partial paralysis, pain or inattention to one entire side of the body. It prevents individuals from doing the things they do in their daily lives, such as dress themselves or go to the bathroom independently.
COVID-19 and Psychiatric Disorders
Either through neuroimmune signalling or by directly entering the cells of the brain, COVID-19 also contributes to psychiatric symptoms and disorders. It is unclear what role it may play in their pathology, but it may worsen existing conditions or as a contributing factor in its development.
One study compared individuals afflicted with the novel coronavirus to those in quarantine or the general public, finding elevated rates of depression (29.2%) in those with COVID-19. Another small study reported increased post-traumatic stress symptoms in these patients.
Individuals already living with psychiatric disorders reported a worsening of symptoms in two different studies. Several other studies reported depressive and anxious symptoms worsened among essential workers.
Another study surveyed >2000 individuals in Denmark, finding a reduction in overall psychological well-being measures during the pandemics. This study also reported that women were more negatively affected than men.
Additionally, it recognized that many older adults living in adult-care communities during shelter-in-place orders experience loneliness and depression. A study of older adults in San Francisco found that they showed increased rates of loneliness and depression.
We must do our best to check-up on our friends and loved ones. We are all affected differently by the pandemic, so it is important to recognize that the rates of anxiety, depression and stress-related disorders may arise.
Thousands of individuals initially infected with COVID-19, the long-haulers, continue to suffer symptoms many months later. On average, these individuals are women around the age of 44 who are otherwise healthy. Their infections were classified as mild severity because they could recover at home.
Facing stigma and in need of a community, several groups sprouted up to support each other. Originally disbelieved, they rallied to raise awareness of their predicament within the medical establishment. It should no longer be sufficient to classify individuals infected with COVID-19, who don’t require a hospital stay, as mild.
A few different studies report that most individuals affected with COVID-19 suffer from symptoms months later (Italy, UK, Germany). Intriguingly, many long-haulers did not produce high-levels of coronavirus antibodies. Many individuals experience pain, fatigue and many other debilitating symptoms.
These symptoms are consistent with disturbances in the autonomic nervous system, which is responsible for many automatic physiological functions like breathing or heart-rate but also influence fatigue. Preliminary physiotherapy involves reconditioning the nervous system of patients so that they may regain some of these functions. In his article, Ed Yong states:
No matter the exact diagnosis, the COVID-19 pandemic will almost certainly create a substantial wave of chronically disabled people.
The coronavirus impacts our brain and nervous system through many different pathways. Whether the mechanisms involve inflammation, stroke or direct entry into brain cells, the results are debilitating. Some of those affected suffer from a stroke or worsening of psychiatric symptoms.
Some COVID-19 patients may develop stress disorders or even show symptoms lasting months after the initial infection. Healthcare workers or those of us who remain socially isolated from others suffer from a reduction in psychological well-being.It’s also important to note that there are severe racial disparities in testing, treatment and mortality, resultant of racist practices.
It’s clear that the public policy needs to catch up with science. People who remain ill should receive compensation while institutions must prepare for a vast increase in chronic illness after the pandemic.