Oh! Hey there, Brainiacs.
Well it’s week...who even knows of quarantine, and you’ve probably already read every article
and watched every video you could find about the coronavirus.
Most of those have focused on what coronavirus is doing to our society, our economy, and
our lungs.
But as a neuroscientist sitting here in at home, what I’m most curious about is: what
is it doing to our brains?
By now we’ve all got the symptoms of COVID19 memorized: dry cough, fatigue, and a fever.
You might even know about some of the more obscure symptoms, like a sore throat, diarrhea,
and aches and pains.
We’re learning more every day about this virus, and working out new ways to combat
it in our communities.
Most of what we hear about the effects of COVID19 are about what it can do to our respiratory
system.
The SARS-CoV-2 virus, which is the official name of the virus itself, seems to enter the
body via the nose or mouth, binding onto cells using the cell-surface receptor called angiotensin-converting
enzyme 2, or ACE2.
The virus injects its genetic material, called RNA, into the cells and hijacks their machinery
to make more copies of itself, which go on to attack more cells.
Eventually, the virus can make its way down the throat to the lungs, where it takes up
residence and wreaks even more havoc.
In the tiny air sacs where oxygen gets absorbed into the bloodstream, called the alveoli,
the fight between your immune system and the virus can cause inflammation, cell death,
and excess fluid, a combo that leads to pneumonia.
Sometimes, when the infection is really bad, patients end up with acute respiratory distress
syndrome, or ARDS, when their lungs are so clogged up that their bodies aren’t able
to absorb enough oxygen and they really struggle to breathe.
This is usually when a person ends up requiring ventilation to support their breathing - and
even that doesn’t always work.
But the danger isn’t only to your lungs - it's to your whole body, including your
brain.
As the number of COVID19 cases climbs, doctors and scientists have noted more and more symptoms
linked to the central nervous systems - severe headaches, for one, and loss of sense of taste
and smell for another.
Other reports include seizures and strokes, and a recent case report even identified a
COVID19 patient suffering from acute necrotizing hemorrhagic encephalopathy, where the inflammation
in her brain led to memory loss and disorientation.
So what’s going on here?
Well, again, since SARS-CoV-2 is a new virus, we’re not entirely sure.
A lot of this hinges on whether or not the virus can cross the blood brain barrier.
Because the brain is so fragile and easily damaged, it’s evolved a special set of blood
vessels that are extra-effective at keeping most things, like foreign pathogens, out of
the brain.
It’s called the blood brain barrier and you can watch a whole video we made on that
by clicking in the corner or checking out the description.
So the blood brain barrier is great for preventing infection, but also bad for getting drugs
into the system to treat any infections that make it through.
Case studies on patients have found conflicting evidence as to whether or not SARS-CoV-2 can
cross the blood brain barrier, but some preliminary research in China seems to indicate that it can.
And like anything that causes inflammation in the brain, that’s bad news bears.
Inflammation in the brain can cause a whole host of problems, most notably swelling, or
encephalitis.
That swelling puts pressure on the brain, causing everything from mild, flu-like symptoms
and headaches on up to seizures, hallucinations, paralysis, and loss of consciousness.
Viruses like the flu or other coronaviruses can also kill brain cells called oligodendrocytes,
which wrap around neurons and act as insulation to help them send signals.
When oligodendrocytes die, this results in demyelination of neurons, which can lead to
muscle weakness, vision problems, pain, and changes in sensation, among other things.
Viral infections can also activate the brain’s immune cells, called microglia, and make them
attack the brain’s healthy tissue when they shouldn’t be.
So can SARS-CoV-2 do all of that?
Well...we don’t know.
We’re still trying to get a handle on what, exactly, this virus does to the body, and
to the brain.
So far, it doesn’t seem like neurological issues are /primary/ warning signs of a SARS-CoV-2
infection, but some case reports indicate that these symptoms, especially headaches,
can show up days before the dry cough or fever, meaning they might be good indicators for
when a patient should be isolated and tested for the virus.
But, even if SARS-CoV-2 doesn’t primarily attack the brain, that doesn’t mean we won’t
see a wave of psychiatric and neurological issues following this pandemic.
Researchers at UC San Diego published a paper in April of 2020, just a couple of months
after the pandemic began, to warn the scientific and medical community that patients who have
been exposed to or recovered from COVID19 should be carefully monitored for neurological
issues going forward.
Based on past influenza pandemics, like the one in 1918, they say that we should be on
the lookout for possible increases in cases of insomnia, anxiety, and depression, in addition
to the risks we’ve already mentioned.
And all of this doesn’t even touch on the ways in which physical isolation, the anxiety
of living in a pandemic, worrying about our loved ones and our health, and the stress
of financial uncertainty can all independently cause serious mental strain.
We’re still learning what the long term effects of this virus will be - and not just
on our brains, but on...everything.
But this isn’t all doom and gloom!
Thanks to technology, we’re better connected with each other than we ever have been in
the past; we’re able to FaceTime with our grandmas, play video games with our friends,
and swap favorite sourdough recipes with our internet communities.
There have been some incredible acts of generosity and kindness, and sharing our vulnerabilities
and fears can help get them out in the open, giving our support system a chance to prop
us up when we need it most.
If you’re having a hard time with social distancing, Micah made a video not that long
ago about how to better deal with it.
Please, please take this virus seriously.
It’s a very scary and stressful time, and it’s understandable that we’re all feeling
impatient for things to go back to normal.
I’m sad that I don’t get to spend time on the beach, or visit with my friends, or
go camping or hiking.
But I know that this virus is very real, and very dangerous, and I’ll stay at home to
protect myself and those around me.
I hope you will, too.
How are you doing, Brainiacs?
What have you been spending your time on?
If you’re one of the cool people still watching, drop a comment with your favorite sourdough
recipe...or any bread recipe I suppose!
Just comment something about bread.
That’ll really confuse everybody else.
Thanks for watching this episode!
Until our next transmission, I’m Alie Astrocyte. Over and out.