How COVID Kills Some People But Not Others - Doctor Explaining COVID

COVID 19 how does this coronavirus SARS  coronavirus to kill people why does it   kill some people but not others welcome to another  video for those of you who don't know me I'm   Doctor Mike Hanson a real doctor who specializes in  pulmonary medicine critical care medicine and   internal medicine when I'm not working in the  hospital or the pulmonary clinic I'm at home   working on making these videos for you to deliver  you accurate medical expertise to the best of my   ability especially during this pandemic if you  want to verify my credentials feel free to do   so on this website from the American Board  of Internal Medicine here you can see that   I'm board-certified in all of my specialties Wow  I look so young back then so this virus we know   is mainly transmitted by respiratory droplets  and through contact and it gets into our mucosa   of our mouth our nose and our eyes although less  common it can also be transmitted through aerosol   meaning airborne most likely when you have people  in an enclosed space such as an elevator or when   someone sneezes or coughs without covering their  mouth especially an elevator and then someone can   inhale that aerosol and that's how that is mainly  transmitted when it's done through aerosol but   most of the transmission is going to be through  respiratory droplets and or through contact this   virus attaches to cells in our body by the ACE  to receptor this h2 receptor is only located on   certain cells in our body it's on our tongue it's  in our nose it's in the back of our throat and   it's in our lungs specifically within the lungs  it's only located on our type ii alveolar cells   what's that you ask let's take a closer look at  our lungs all right so we're gonna deep dive into   this power point that I created and we're gonna  start off by getting into the lungs here is our   windpipe aka the trachea this is going to divide  into our right mainstem bronchus and this is our   left mainstem bronchus and just like branches on  a tree these gonna keep branching the smaller and   smaller branches same thing with this long and  then eventually it's gonna bring so small that   it's gonna become like that the leaves on the tree  and this is called the alveolus here alveolus is   me comprised of type 1 alveolar cells that is what  actually forms a structure of the alveolus here   but that's not everything the other kind of cell  is the type 2 alveolar cell and that's this thing   right here and that's important because that's  where the taste to accept is located within our   alveoli this right here is a macrophage this is a  kind of white blood cell macro means big and then   phage means to eat this yellow stuff right here  is called surfactant it's like lubrication for   the alveoli it's very important to keep the lvi  oh oh the alveoli open but also it's important   to make sure that the alveoli is not too stiff  so that's lubrication makes it nice and smooth   here we have a fibroblast this is a cell that is  responsible for maintaining the structure of the   lung tissue and they also do maintenance shut up  - all the maintenance people custodians thank you   very much this right here is a capillary this is  a pulmonary capillary and you can see it's gonna   come in close proximity to the alveolus and this  is where gas exchange occurs so when we breathe   in air comes down here the oxygen and air is  gonna diffuse through the type 1 alveoli into   a capillary and go into the red blood cell and  carbon dioxide is gonna go from our red blood cell   carbon dioxide to co2 it's gonna diffuse from the  red blood cell through this membrane then through   this membrane and then into the alveoli and then  we're gonna exhale that co2 it's gonna go up that   way now besides this red blood cell you see you  also have a neutrophil here that's another kind   of white blood cell think of a neutrophil as like  the police or the military they're just coming by   here and they're just making sure everything is  all good not needed here and then just gonna keep   on moving through here and notice of what this  white blood cell this neutrophil is much bigger   compared to the red blood cell now let's look  at how the virus gets into this alveolar cell   this type to alveolar cell as I said before the  type 1 viola don't have these h2 receptors but   the type to do have them so the coronavirus are  gonna come down to the type 2 alveolar cell and   is gonna go up to the receptor anybody like and  then this h2 receptor is like well it's a good fit   it's a good bind here so let's the corona virus  into the house and the next thing you know he's   asking if she wants eggs for breakfast so at this  point the corona virus enters a cell the type 2   alveolus and we have the D I'm sorry the RNA of  the virus here and then it's gonna unravel and   it's gonna make copies of its own messenger RNA  and then it's also going to use that messenger   RNA that it has and use the cell machinery to  make proteins so it's gonna make the proteins   for Spike protein that's gonna make different  parts of proteins for different parts of its   cell the bottom line is it's gonna replicate  itself and make multiple copies and then this   new corona virus that's formed is gonna go and  attack other type ii alveolar cells now this is   important because it's gonna trigger a cascade  of reactions it's gonna trigger this cytokine   storm but it's also gonna down regulate this ace 2  receptor which is very important and I'll explain   that a little bit at some point the nucleus of  the cell which is right here is gonna recognize   that this whole process of the virus replicating  itself this is not supposed to be here this is a   foreign invader and it's gonna trigger a release  of chemicals that send a distress signal this is   the initiation of the cytokine storm the other  thing this virus is affecting this nucleus when   it comes to the down regulation of this base  2 receptor this is an enzyme in the body that   serves a specific purpose and we're gonna talk  about the importance of that in a little bit so   as I mentioned the distress signals that are  being sent in the cytokine storm that's gonna   be il-1 il-6 I'll eat in aisle 29 these are all  very important but I want you to pay attention   to aisle 6 now IL stands for no clothes Ken but  it's actually interleukin the down regulation of   this ace to receptor is so important because as  if the cytokine storm isn't bad enough triggering   all the inflammation that's about to happen the  other thing is it does this when there's down   regulation of the h2 there's less ability to  convert angiotensin 2 to injure tensed 1-7 and   there's also less ability to convert angiotensin  1 to angiotensin 1-9 why is this important take a   closer look angiotensin again is a protein made in  the liver renan is a protein made in the kidneys   renin is an enzyme that converts angiotensinogen  to angiotensin one angiotensin one is converted   to angiotensin 2 by this enzyme angiotensin  converting enzyme these two molecules by way of   the h2 enzyme are converted to angiotensin 1-9  into tensed 1-7 this is very important because   this pathway here is going to lead to vasodilation  meaning the blood vessels the pulmonary arteries   get dilated when there's more into your tent  and two and less into tenths of one seven this   is what happens the angiotensin one receptor gets  stimulated and that leads to base of constriction   leads to more information and more fibrosis so  we want the balance of this cascade this series   of reactions to be shifted more towards this  way and less towards this way but that's not   what's happening with this virus in between the  cytokine storm in between the down regulation of   this ace two enzyme and what ultimately happens  is you have more angiotensin 2 in the lungs and   less angiotensin 1-7 this is gonna trigger a crazy  chaotic reaction within the lungs okay back to our   type 2 alveolar cell here remember when we were  talking about this things are normal before but   now they're not so normal remember we talked about  this cell releasing these cytokines this il-6 this   I'll aid this il-1 I'll 29 and also the down  regulation of h2 well that's gonna trigger all   this chaos to happen the red blood cells come in  here but guess what remember that neutrophil we   talked about it's actually attracted to these  chemicals better released so it's gonna find   its way into this alveolar space and here it  is here and it's gonna release more chemicals   leukotrienes pif oxidants proteases these all  destroy stuff they destroy cells remember this   guy the macrophage means big eater well guess  what just like Guns and Roses he's now got   an Appetite for Destruction he's gonna release  tnf-alpha il-6 i'll a il-1 destroying stuff just   eating everything in its path the alveolar wall  here that's gonna be destroyed through all this   destruction this membrane here of the endothelium  that's gonna be destroyed fluid is gonna seep from   this capillary into the alveolus all this  yellow stuff here that's all fluid all this   pink stuff that's hyaline membrane that's protein  deposition proteins are being deposited there and   also because of the destruction in this membrane  here the red blood cells they're gonna leak into   there that's called bleeding this fibroblast is  gonna make more destructive stuff more cytokine   storm il8 it's gonna lay down pro collagen which  is the precursor to collagen that's gonna bleed to   scarring in the area this is all bad stuff this  is what it looks like underneath the microscope   this is normal this is normal alveoli underneath  the microscope this is what it looks like with   ARDS from COVID 19 this was actually taken from  a patient who died of COVID 19 and you can see   what I was talking about the Highland membrane  formation that deposition of all those proteins   and cellular debris it's all crazy here right and  then you have lymphocytes the white blood cells in   here and then you have this is of the other lung  the same patient you have a big macrophage here   and all these lymphocytes spread throughout with  this hyaline membrane deposition this is chaos   this looks like the end of Avengers endgame in a  final scene this is a normal chest x-ray okay here   we have the heart we have the vertebrae here we  have the ribs okay we have the diaphragm that's   the biggest muscle that controls your breathing  okay you have a scapula here the collarbone the   clavicle there all right now all this black that  represents air that normal this kind of white   hazy stuff that's the pulmonary blood vessels  okay that's all normal then this happens from   a COVID patient with aired yes look at all that  it's hardly any black there all the air is gone   all right how is that oxygen supposed to get  into or through the alveoli into the pulmonary   capillary how is that supposed to happen this  is a cat scan of a normal person normal lungs   okay so they're laying down on their back here  alright and then you're standing at their feet   and you're looking towards their head and this  is a thin slice in cross-section the black stuff   represents air and this white stuff is actually  the pulmonary vessels the pulmonary arteries and   pulmonary veins alright so this is normal this  is the CT scan of someone with air - yes there's   some normal lung in here but there's also areas  of ground glass of pacification that's partial   or pacification or partial filling of the alveoli  and then you see it's more dense here okay that's   complete or pacification that's complete filling  of the alveoli with fluid and inflammation now   as if this isn't bad enough where the alveoli  are either partially or completely filled with   fluid and inflammation and protein and all that  stuff well what I didn't mention to you before was   these purple dots here that represents very tiny  thrombi very tiny clots that form as a result of   all this inflammation what does that do that's  gonna clutter those little capillaries that's   gonna clutter the blood flow that goes to the  lungs and as if that's not bad enough there's   another thing that's very very bad when it comes  to ARDS especially in COVID 19 patients and that   has to do with pulmonary hypertension meaning the  pulmonary arteries that go to the lungs they're   gonna constrict and that's not good the reason why  they're constricting so much at least part of the   reason why is because they have angiotensin ii so  much angiotensin ii related to that ACE 2 receptor   down regulation so this increase in angiotensin 2  is going to cause the blood vessels to constrict   and that makes it harder for the right side of the  heart to pump and this is going to ultimately mean   less oxygenation than normal as if oxygenation  wasn't a big enough problem already now we've got   a third reason why the oxygenation is gonna be  so bad let's review our heart physiology so the   pulmonary vein this is the blood that's coming  back from the lungs it's gonna be oxygenated   because the blood that goes to the lungs gets  oxygenated there so now it's coming back and   it's gonna go into the left atrium of the heart  then it goes to the left of ventricle to heart   then it's gonna be pumped out to the body through  the aorta and this blood gets pumped to the body   it's gonna go to the brain it's gonna go to the  intestines to the kidneys it's gonna go to your   legs to your arms to your muscles more if it goes  to your muscles when you're working out let's say   you drain your biceps blood is rushing into your  muscles and that's would record a pump Thank You   Arnold now when the blood comes back from the  body from those places that I just mentioned   it's gonna come back through the vena cava the  biggest fan in the body there's a superior vena   cava and an inferior vena cava and that's gonna  land that blood into the right atrium then the   blood from the right atrium is gonna go to the  right ventricle and then to the pulmonary artery   and then from the pulmonary artery it's gonna be  sent off to the lungs to go pick up oxygen again   because it's deficient in oxygen but the problem  like a dis mention is now that vasoconstriction   of those pulmonary arteries that's gonna lead to  less blood flow getting to the lungs so there's   less blood flow that can get oxygenated and  so what ultimate is gonna happen is you're   gonna have even lower oxygen levels than you would  expect normally with ARDS because of that reason   so there's really three reasons why patients with  ARDS have such a difficult time with oxygenation   ones because of all the inflammation from air ds2  is because the micro thrombi that developed this   tiny little clots that form in the capillaries  and three is this pulmonary vasoconstriction   it's pulmonary hypertension that develops and  ultimately the oxygen levels are just gonna drop   very very low now there's a lot of people asking  about ACE inhibitors angiotensin receptor blockers   so ACE inhibitors are things like captopril of  sinop rael ramipril and due attention receptor   blockers are things like losartan Telma Sartain  candy Sartain or bizarre tan here's how these   things work ACE inhibitors inhibit the ACE enzyme  so there's gonna be a blockage in this part of the   cascade and what happens here is if you put a  roadblock here that's gonna shift this sequence   to this way alright it's gonna go down that way  now if you have a blockade right here in this   part of the pathway by an angiotensin receptor  blocker such as a low start in these medications   inhibit binding to this receptor here alright so  if you inhibit it here it's gonna shift everything   towards this way and towards this way and you're  gonna have this right here that's good that's what   we want we want to dilate those pulmonary arteries  we want to reduce inflammation we want to reduce   fibrosis that's good so that's why I think the  trials that these medications are in right now   for over 19 I think we're gonna have great results  of that but only time will tell and everything I   just mentioned to you about a stew in angiotensin  2 in angiotensin 1-7 this is all backed by small   studies going back 10 years ago or so and there's  even more so in the last couple of years because   this is a very hot area of research and I'll  show you some of the studies real quick you got   this one this one there's the intensive one seven  how it relates to here yes and a type ii alveolar   cells there's just lots and lots of studies they  have to do with exactly what I'm talking about   so how do we get COVID 19 patients with ARDS how  do we get these patients better it's gonna be a   combination of things including individualizing  various ventilator settings including adjusting   the tidal volume and adjusting the peep it's  also gonna involve trying different ventilator   modes with assist control possibly aprv it's  gonna involve proning patients meaning lying   patients on their chest instead of their back it's  gonna include the possibility of using pulmonary   vasodilator such as inhaled nitric oxide or  process cycling for IV eople process and all flow   and it's gonna vol the possibility of steroids  possibly ECMO and of course the medications that   are coming out for COVID 19 veteran clinical  trials and some are more promising than others   and that's going to be the topic of my next video  okay so we know that ARDS develops in about four   to five percent of patients with COVID 19 and all  these people who get COVID 19 the mortality rate   is around one to two percent so why do some COVID patients get ARDS and why do some die it could   be one of these reasons but more likely it's a  combination of these reasons so here we go number   one the virus only gains entry into our cells  that Express the ACE 2 receptor they're located in   multiple sites besides being in your lung during  your mouth nose throat stomach during their small   intestine the colon skin not on the outside of the  skin but on the underneath the skin lymph nodes   thymus bone marrow spleen liver kidneys brain and  one more place yeah that's right there in your   testes if you have those all right number two it  makes sense that if the virus only gets into your   mouth or nose or throat but not the lungs that  it recalls only cold like symptoms but if the   virus gets all the way down into your alveoli your  lungs specifically the type 2 alveoli that's where   you're gonna have ARDS potentially developed and  by the way the ace 2 receptors that are in your   gut probably explained by some patients end up  getting nausea vomiting diarrhea okay number three   the amount of virus that you get into your body  likely determines how sick you get this is what we   call the viral load and this was demonstrated in  this study number four the inflammatory reaction   that occurs with COVID 19 is extremely complicated  with lots of different proteins and hormones in   interleukins at play but there are several known  genetic polymorphisms of these proteins that   make the illness potentially worse than others a  genetic polymorphism simply means a variation on   a particular gene for example there are genetic  polymorphisms of the ACE gene not the ACE 2 but   the ACE gene as well as il-6 basically a lot of  it comes down to our genes and sex because the   fifth reason has to do with estrogen estrogen  is known to inhibit the effects of il-6 which   plays a huge role in the cytokine storm this might  explain why women overall have less severe disease   compared to men see ladies aren't you glad  you don't have and the sixth reason has to do   with some people are already on medications that  might impact COVID 19 for people who are already   on ACE inhibitors such as lisinopril or an ARB  such as losartan or telma start an whatever or   people who take hydroxychloroquine for lupus or  rheumatoid disease are people who take tousle ISM   AB in il-6 receptor inhibitor are these patients  less prone to getting severe illness my guess is   yes and now I know there's a theory circulating  out there about how the virus might be attacking   our hemoglobin the theories based on this non  peer-reviewed study that showed that the virus   in a test tube not on our body or in animals but  in the test tube could attack hemoglobin which is   in our blood specifically it's speculated that  it might attack the beta 1 chain of hemoglobin   in our blood even if it could attach to the beta  1 chain of hemoglobin I can tell you that it's   not the way the virus is causing disease we know  this for several reasons one we know abides to   the h2 receptor in gates entry into our cells  that way too we see that with our own eyes the   destruction that it causes to the alveoli on the  pathology number three we know that the COVID 19   patients have a low P to F ratio which means that  the reason for low oxygen is because the lungs   reduced ability to move oxygen from the air into  your bloodstream and people who have low oxygen   levels due to an issue with the hemoglobin for  example with methemoglobinemia they have a normal   p2f ratio patients with met him aglow of anemia  have a low oxygen saturation but in normal PDF ratio   in COVID 19 ARDS these patients have a low  p2f ratio okay number four the red blood cell does   not have h2 receptors located on it so the virus  is not able to invade the red blood cell number   five hemoglobin normally does not exist outside of  the red blood cell except when the red blood cell   bursts what we call hemolysis and COVID 19 patients  were not seeing any hemolysis therefore there's no   way the virus is able to attack hemoglobin except  for perhaps a very tiny bit of hemoglobin that can   exist in alveoli as a result of the alveolar  damage from ARDS all right so that's all for   this video in my next one it's going to be on  the new drugs that are in clinical trials some   of these drugs are looking more promising than  others so I'm excited to get this one to you

Channel: Doctor Mike Hansen

Views: 4,596,163

Rating: 4.8358045 out of 5

Keywords: how covid kills some people but not others, how covid works inside your body, how covid works in human, how covid kills, how covid kills a person, how covid kills i'm a doctor, how covid kills human, how covid kills patients, how covid kills u, how covid kills some people, how covid virus kills you, covid virus how it kills you, how does covid kills you, covid explained by doctor, how does covid affect, how does covid affect the body, why some people die from covid, covid

Id: LV8wWhjTKRU

Length: 22min 41sec (1361 seconds)

Published: Wed Apr 15 2020

Reddit Comments

[u/Positive-Vibes-2-All]

This is extremely informative, clear and in-depth. Really helpful. Thanks for posting