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OK HEAR ME OUT: I absolutely love
the topic of carbon monoxide (CO)...but I feel like we learn about it all wrong in med school.
Let's talk about carbon monoxide and how it causes badness--I promise 
this will be interesting! A thread... /1
the topic of carbon monoxide (CO)...but I feel like we learn about it all wrong in med school. Let's talk about carbon monoxide and how it causes badness--I promise this will be interesting! A thread... /1
Many of us learn about carbon monoxide in the following way: our red blood cells 
contain HEMOGLOBIN which carries OXYGEN to our organs. When you breathe 
in CO, it binds super duper tightly to hemoglobin and creates CARBOXYHEMOGLOBIN. /2
contain HEMOGLOBIN which carries OXYGEN to our organs. When you breathe in CO, it binds super duper tightly to hemoglobin and creates CARBOXYHEMOGLOBIN. /2
Hemoglobin and CO have a relationship similar to me and cats--essentially OBSESSED with each other
. There's no room for oxygen in that relationship. No oxygen on hemoglobin = cells/tissues/organs don't get oxygen delivered = badness occurs. /3
. There's no room for oxygen in that relationship. No oxygen on hemoglobin = cells/tissues/organs don't get oxygen delivered = badness occurs. /3
But what if I told you there is MORE to the tale of carbon monoxide....!? 
/4
/4
Imagine if you had a group of animals named Cute Animals 
. If those Cute Animals inhaled CO for 15min, they died 
within the 1hr. You're probably thinking, "Well duh, their hemoglobin can't bind oxygen anymore so of course they are going to die." HMMM... /5
. If those Cute Animals inhaled CO for 15min, they died within the 1hr. You're probably thinking, "Well duh, their hemoglobin can't bind oxygen anymore so of course they are going to die." HMMM... /5
Now imagine you have a different group of animals named Adorable Animals 
. If these Adorable Animals were bled out (losing their own blood) and transfused with blood from Cute Animals (blood that contained 80% carboxyhemoglobin!)....what would happen to them? /6
. If these Adorable Animals were bled out (losing their own blood) and transfused with blood from Cute Animals (blood that contained 80% carboxyhemoglobin!)....what would happen to them? /6
The group of Adorable Animals would live! 
This is because the problems from CO don't stem from just the formation of carboxyhemoglobin, but rather, from what else the CO does. /7
This is because the problems from CO don't stem from just the formation of carboxyhemoglobin, but rather, from what else the CO does. /7
Although we routinely check carboxyhemoglobin levels, there's so much more to CO than that. In order for CO to even reach tissue (such as the brain
, which is the scariest part of this whole thing), it needs to be dissolved in the blood (plasma), not bound to hemoglobin. /8
, which is the scariest part of this whole thing), it needs to be dissolved in the blood (plasma), not bound to hemoglobin. /8
Carboxyhemoglobin is most def very annoying. But you know what's even MORE annoying? Carbon monoxide directly interfering with cellular respiration (via binding to cytochrome oxidase). Ischemic reperfusion injury of the brain. Neuronal cell death. 
I could go on! /9
I could go on! /9
But we never talk about any of this in medical school. At least I didn't. I went back and looked at my med school notes for CO and this is what I found: /10
I don't think you need to be in a toxicology fellowship to appreciate that there's more to CO than just carboxyhemoglobin. However this begs to question...what other knowledge is out there waiting to be learned? 
Keep asking questions and never stop learning! /11
Keep asking questions and never stop learning! /11
Disclaimer: no animals were harmed in the making of these tweets. Dogs were the test subjects, however, in the original study, found here: http://www.annclinlabsci.org/content/6/4/372.full.pdf. Also shout out to my wonderful fellowship program ( @ToxNyu) for enabling me to learn so much every day. /fin
