New findings show Sars-CoV-2 can affect the brain


Scientists are only starting to grasp the vast array of health problems caused by the novel coronavirus, some of which may have lingering effects on patients and health systems for years to come, according to doctors and infectious disease experts. Since the start of the pandemic, it has become increasingly clear that Sars-CoV-2 is not just a turbo-charged version of the virus that causes the common cold; it has a number of quirky, unusual and sometimes terrifying traits. While coronavirus symptoms typically resolve in two or three weeks, an estimated one in ten experience prolonged symptoms, Dr. Helen Salisbury of the University of Oxford wrote in the British Medical Journal on Tuesday.
Virologists will spend years trying to understand the biomechanics of this invader. And though researchers have scrutinized the virus and its victims for six months, publishing scientific studies at a rate never before seen with any disease, we still have more questions than answers. The newest to be added is: can the virus infect the brain?
Estimates of exact prevalence vary, but it seems that roughly 50% of patients diagnosed with Sars-CoV-2 – the virus responsible for causing the illness COVID-19 – have experienced neurological problems. Dr. Igor Koralnik, chief of neuro-infectious diseases at Northwestern Medicine, reviewed current scientific literature and found about half of patients hospitalized with COVID-19 had neurological complications. These upper body complications range from headache, dizziness and loss of taste or smell to seizures and confusion.
Koralnik, whose findings were published in the Annals of Neurology, has started an outpatient clinic for COVID-19 patients to study whether these neurological problems are temporary or permanent.
For Julie Helms, it started with a handful of patients admitted to her intensive care unit at Strasbourg University Hospital in northeast France in early March 2020. Within days, every single patient in the ICU had COVID-19 – and it was not just their breathing difficulties that alarmed her. They were extremely agitated, and many had neurological problems – mainly confusion and delirium. Helms used to have some patients in the ICU who are agitated and require sedation, but this was completely abnormal. It has been very scary, especially because many of the people we treated were very young – many in their 30s and 40s, even an 18-year-old.
Helms and her colleagues published a small study in the New England Journal of Medicine documenting the neurological symptoms in their Covid-19 patients, ranging from cognitive difficulties to confusion. All are signs of “encephalopathy” (the general term for damage to the brain) – a trend that researchers in Wuhan had noticed in coronavirus patients there in February. Now, more than 300 studies from around the world have found a prevalence of neurological abnormalities in COVID-19 patients, including mild symptoms like headaches, loss of smell (anosmia) and tingling sensations (arcoparasthesia), up to more severe outcomes such as aphasia (inability to speak), strokes and seizures. This is in addition to recent findings that the virus, which has been largely considered to be a respiratory disease, can also wreak havoc on the kidneys, liver, heart, and just about every organ system in the body.
Most researchers believe the neurological effect of the virus are an indirect result of either oxygen starvation to the brain (the “happy hypoxia” exhibited by many patients), or the byproduct of the body’s inflammatory response (the famed “cytokine storm”).
In fact, some scientists now suspect that the virus causes respiratory failure and death not through damage to the lungs but through damage to the brainstem, the command center that ensures we continue to breathe even when unconscious.
The brain is normally shielded from infectious diseases by what is known as the “blood-brain barrier” – a lining of specialized cells inside the capillaries running through the brain and spinal cord. These block microbes and other toxic agents from infecting the brain. Evidence is starting to accumulate demonstrating that the virus can actually invade the brain itself. In Japan, researchers reported the case of a 24-year-old man who was found unconscious on the floor in a pool of his own vomit. He experienced generalized seizures while being rushed to hospital. An MRI scan of his brain revealed acute signs of viral meningitis (inflammation of the brain), and a lumbar puncture detected Sars-CoV-2 in his cerebrospinal fluid. Chinese researchers also found traces of the virus in the cerebrospinal fluid of a 56-year-old male patient suffering from severe encephalitis. And in a post-mortem examination of a COVID-19 patient in Italy, researchers detected viral particles in the endothelial cells lining the blood vessels of the brain itself.
Sherry Chou, a neurologist at the University of Pittsburgh, has coordinated scientists from 17 countries to collectively monitor the neurological symptoms of the pandemic, including through brain scans.
Chou maintains that even though neurological symptoms are less common in Covid-19 than lung problems, recovery from neurological injuries is often incomplete and can take much longer compared to other organ systems (for example, lung), and therefore result in much greater overall disability, and possibly more deaths.
Patients experiencing lung failure can be put on a respirator, and kidneys can be rescued with a dialysis machine – and, with some luck, both organs will bounce back. But there is no dialysis machine for the brain.
In an update on COVID-19 Dr. Marvin Manzanero, Director of Health Services has stated that “There is also no specific vaccine. We need to say that. And based on what is happening over the last couple of weeks with what we know of the virus, it doesn’t seem that we are going to go back to where we were prior to SARS-CoV2 unless there is a vaccine. And why?”
He continued, “This is very important – the recent data seems to suggest that the immunity, which means if I become infected, I am not going to be to produce enough antibodies for a sustained period. It would seem to be that it is only going to be for a period of months and after that it would mean that I would be susceptible to a new infection from the same virus.”