Now the mnemonic, which I'm going to put on the slide, but I just want to show you first, is a fat nurse hemolyzed my labs. A fat nurse hemolyzed my labs. Now let's put that across the bottom and I'll explain these as we go.
So the first type of transfusion reaction is the allergic, sometimes called anaphylactic transfusion reaction. And the way that you remember that is using our mnemonic that a fat nurse hemolyzed my labs. So the A in A Fat Nurse, is our first blood transfusion reaction.
So A for allergic or A for anaphylactic. Now this is a type 1 hypersensitivity reaction that occurs due to plasma proteins in the blood that the patient is receiving. Specifically, they're going to experience symptoms like any allergic reaction or any anaphylactic reaction.
So things like itching or pruritus, urticaria, and if it's really profound, septic shock. Okay, so these are all of the symptoms that you would classically find in any allergic reaction. So think about somebody who's allergic to peanuts and eats a nut, right?
Itching, wheels, septic shock if it's really, really severe. The timing is going to occur in about two to three hours. So two to three hours for our allergic or anaphylactic blood transfusion reaction. Now something that's very, very high yield that ties in beautifully with this mnemonic is that patients with IgA deficiencies are at huge risk. of allergic transfusion reactions.
Enormous risk. And we can remember that easily because IgA has A in it. And A for allergic, anaphylactic, and A, fat nurse, hemolyzed my lab. So it goes beautifully with the mnemonic. So just to summarize, the first type of blood transfusion reaction is the allergic transfusion reaction, where the patient has sort of like an allergic reaction to the blood that they're receiving.
This is due to plasma proteins in the blood. You're especially at risk for this if you have an IgA deficiency. The symptoms are all the symptoms that you classically see in an allergic reaction.
So, pruritus or tachyuria, respiratory depression and shock if severe. And this occurs on the order of two to three hours. That is our first type of blood transfusion reaction, which you can remember by saying to yourself, a fat nurse hemolyzed my labs. An A for allergic and A for IgA deficiency.
Our second type of transfusion reaction is the febrile non-hemolytic type. Okay, febrile. non-hemolytic blood transfusion reaction.
And the way that you remember this is with the second part of our mnemonic here, the second part of our sentence, fat nurse. Fat nurse, F in fat for febrile and N in nurse for non-hemolytic. Now, this is a type 2 hypersensitivity and this occurs when the host antibodies react against the donor's white blood cells. Okay, so there's white cells that are going to be in the blood that the donor or the donor blood has.
And the host will form antibodies against those white cells, have a type 2 hypersensitivity reaction. And that is the basis for this transfusion reaction. Now, specifically, there are cytokines in the blood, right? Every blood, everybody who has blood has cytokines in it.
And what happens here is that when that blood is stored in the blood bank in the hospital waiting to be used to give a patient blood, those cytokines are actually accumulating. accumulating and they cause this sort of massive a response in the form of a febrile non-hemolytic reaction. So the symptoms are going to be fever, headache, and flushing.
And I want you to pay very special attention to the name of this reaction. So it's called febrile non-hemolytic. So febrile tells you that you're going to see fever. Okay, so if you see fever in the vignette, it's probably febrile non-hemolytic. But even more so, it's non-hemolytic, right?
There is no hemolysis. So you're not... going to see symptoms of hemolysis, which is important because that differentiates this from the next type of blood transfusion reaction that we're going to talk about where you do see hemolysis.
So just the name febrile non-hemolytic tells you fever and no hemolysis. So again, fat nurse, febrile non-hemolytic, non-hemolytic should tell you that there's no hemolysis, so you're not going to see any symptoms of hemolysis. So if you're taking your test, and the vignette is giving you symptoms of hemolysis, then it's clearly not a febrile non-hemolytic transfusion reaction because this one doesn't have hemolysis, hence the name.
So, so far we've said A, fat nurse, A for allergic, and fat nurse for febrile non-hemolytic. So far so good, right guys? Not too complicated.
If you keep it simple in the context of the mnemonic. You'll remember this quite easily. Okay, so here's where we are so far.
We're going to move on to our third type of transfusion reaction. Guys, look at this. You already know half of the transfusion reactions, and we've spent, what, four minutes in this video so far?
Next one is the hemolytic transfusion reaction, sometimes called the acute hemolytic blood transfusion reaction. So really all you need to know is that it's the hemolytic one, right? Because when you look at the answer choices, you're going to see allergic, you're going to see febrile non-hemolytic, you're going to see hemolytic, and then you'll see the fourth one, which will...
talk about in just a minute. But all you need to know is that it's hemolytic. So don't worry about all the other words in the name.
It's the one that has hemolytic in it. Now, this one obviously corresponds to the H in our mnemonic. So a fat nurse hemolyzed my lab.
So when blood hemolyzes, it can't be read in the lab of the hospital. So that's what hemolyzed blood is. And that's why the mnemonic makes sense.
But in this one, it's a type two hypersensitivity reaction with both intra and or extravascular hemolysis. So Again, this one is called hemolytic. So this is the one where you're going to see signs and symptoms of hemolysis. No surprise if you look at the name.
This is due to host antibodies against the donor's red blood cells. So the host antibodies react against the donor's red blood cells in the blood and then will cause intra or extravascular hemolysis and lyse those red blood cells causing signs and symptoms of hemolysis. And again, just to beat the dead horse, it's called hemolytic.
It's the hemolytic blood transfusion reaction, so you see hemolysis. Therefore, let's look at our symptoms. Flank pain, hemoglobinuria, and jaundice. So, flank pain is due to hemolysis occurring in the kidneys. When hemolysis occurs in the kidneys, you get a microangiopathic injury to the kidneys.
You're going to get symptoms of flank pain. Hemoglobinuria, well, you're lysing red blood cells and you're spilling hemoglobin out, which is going to be excreted into the urine, so you're going to see dark urine. right?
That's intravascular hemolysis. And jaundice is obviously a sign of extravascular hemolysis. You should know that if you've been studying at all.
So if you see jaundice, dark urine, aka hemoglobinuria, or flank pain due to hemolysis occurring in the vasculature around the kidney, these are all signs and symptoms of hemolysis. So you know that this is the hemolytic blood transfusion reaction. A fat nurse, hemolyzed, H in hemolyzed, H in hemolytic, my labs.
And this occurs in one hour. Let's talk about our last blood transfusion reaction. So that's the lung injury.
I call it the lung injury transfusion reaction. You might see it as acute injury to the lung due to blood transfusion. Whatever it is, it's the one that has lung in the name. Okay. So a fat nurse hemolyzed my labs.
L in labs, L in lung. So this is when donor anti-leukocyte antibodies attack the recipient. endothelial cells of the lung.
So in the donor's blood, there are antibodies. And once the blood is given to the patient, those antibodies, which are still formed, go specifically into the lung and attack the endothelial cells of the lung. So they destroy the host's lung or they destroy the patient receiving the blood's lung. Okay. Now, because of this, it's injuring the lung.
So what symptoms will we see? We'll see things that injure the lung, no surprise. Things like respiratory collapse and pulmonary edema.
So anytime that you're injuring cells in the body, it doesn't matter where it is, you're gonna see signs of inflammation. So edema, ruber, pain, aka dolor, right? We're talking Latin now. So you see edema in the lungs, pulmonary edema, no surprise, because we're seeing damage to lung tissue.
Respiratory collapse, because there's too much inflammation going on, and that's gonna back up and cause right-sided heart failure. Now this will occur. on the order of one to six hours. Now, let's pause for a second.
How important is it for you to know the timing of these different reactions? It's really not that important, but if you're going to shove it into your brain, I put it on this slide just for completeness sake. But again, lung injury transfusion reaction, donor antileukocyte antibodies against the host or the recipients, endothelial cells of the lungs, causing pulmonary edema, respiratory compromise, possibly right-sided heart failure if it's really severe, and it will occur in one to six hours. hours. But guys, that's it.
This is the summary slide. You now know all of the transfusion reactions because when you think about blood transfusions, you say to yourself, who gives the blood? And the answer is a fat nurse. And then the mnemonic, of course, is a fat nurse hemolyzed my labs.
If you know that, you know these transfusion reactions, you'll get every question right on test day. Remember to keep it simple, keep it stupid, and you will do well.