rvallee
Senior Member (Voting Rights)
How Covid-19 can damage the brain
https://www.bbc.com/future/article/20200622-the-long-term-effects-of-covid-19-infection
Excellent article well worth reading in full. Things get even more complicated over time. Seems like questions are piling up before a single answer can be found.
https://www.bbc.com/future/article/20200622-the-long-term-effects-of-covid-19-infection
Excellent article well worth reading in full. Things get even more complicated over time. Seems like questions are piling up before a single answer can be found.
“They were extremely agitated, and many had neurological problems – mainly confusion and delirium,” she says. “We are used to having 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.”
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.
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.
*cough* encephalitis lethargica *cough*Further complicating matters, many people suffering from the effects of Sars-CoV-2 are never actually tested for the virus, especially if they do not exhibit a cough or fever. It means that if they have neurological symptoms, we may never know if this was linked to Sars-CoV-2.
“In fact, there is a significant percentage of Covid-19 patients whose only symptom is confusion” – they don't have a cough or fatigue, says Robert Stevens, associate professor of anaesthesiology and critical care medicine at Johns Hopkins Medicine in Baltimore, Maryland.
“We are facing a secondary pandemic of neurological disease.”
There are other quirks that Stevens has noticed but cannot explain. “Covid-19 patients seem to have a lack of sensitivity to the drugs we normally use – we’ve had to use five to 10 times the amount of drugs for sedation that we would normally use,” he says.
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 centre that ensures we continue to breathe even when unconscious.
Maybe not so much rare as missed.If Sars-CoV-2 can cross this barrier, it suggests that not only can the virus get into the core of the central nervous system, but also that it may remain there, with the potential to return years down the line.
Though rare, this Lazarus-like behaviour is not unknown among viruses: the chickenpox virus Herpes zoster, for example, commonly infects the nerve cells in the spine, later reappearing in adulthood as shingles – roughly 30% of people who experienced chickenpox in childhood will develop shingles at some point in their lives.
Other viruses have caused far more devastating long term impacts. One of the most notorious was the influenza virus responsible for the 1918 pandemic, which caused permanent and profound damage to the dopamine neurons of the brain and central nervous system. (While it’s long been assumed that influenza cannot cross the blood-brain barrier, some scientists now think that it can). An estimated five million people worldwide were hobbled by a form of extreme exhaustion known as “sleepy sickness” or “encephalitis lethargica”.
Nutt plans to enroll 20 Covid-19 patients who developed depression or another neuro-psychiatric condition into a study that will use Imperial’s state-of-the-art PET scanners to look for signs of brain inflammation or abnormalities in neurotransmitter levels.
In Baltimore, Stevens is also planning a long-term study on Covid-19 patients discharged from the ICU, which will also conduct brain scans as well as detailed cognitive tests on functions such as memory capacity.
And in Pittsburgh, through the Global Consortium Study of Neurological Dysfunction in Covid-19, 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.
“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 death,” she says.