Welcome to another MedCram lecture. The first in the series that we're going to talk about as we go through the CBC is the WBC, and we'll talk about increased WBC here under the term leukocytosis. Okay, so a couple of points regarding leukocytosis. You know, we're looking at a patient most typically in the hospital, but this could also be seen as an outpatient as well.
You should know that the normal range is about 4.5 to 11. And then you'll have this term times 10 to the ninth, which is like a billion divided into one liter. So how many cells do you see in one liter? So obviously anything greater than 11 is gonna define leukocytosis, okay? But it can go as high as 100,000. You wanna watch trends as we talked about in the first video.
So a 13 on a white blood cell count may be elevated, but if the previous one was 20 and it's coming down to 13, then that's a process that's actually resolving and 13 is not to be worried about. If on the other hand, you've got a five and it's going to 13, that's something that obviously we need to worry about more, okay? So again, as always, watch the trends.
And then differential. So the white count, as you may know, are white blood cells. That's what the leuko means.
That's white. So these white blood cells are part of your immune system, but these white blood cells are actually a collection of other cells. There are bands.
There are segmented neutrophils, we call those segs, and these all sort of make up your neutrophils. But then you also have lymphocytes, you have monocytes, you also have eosinophils. So they all have their own function. Typically the bands and the neutrophils are seen elevated in pyogenic infections.
Lymphocytes can also be elevated, but they're usually more typical for viral. Okay, so be aware of that. You also may see this in tuberculosis.
Same with monocytes. You might see monocytes elevated in tuberculosis and also certain viral infections. The one that you should know about though is eosinophils. Anytime you see elevated eosinophils, you need to think about two things specifically.
One is either an allergy. Also think about parasites. So...
Think about drug allergies if you see high eosinophils. Think about parasites. And there's also a third thing that you should think about as well. I'll put it up here. And this is just to keep in the back of your mind is cocci, coccidio mycosis, which is a fungus that typically lives in the southwest United States, also in parts of South America, Central America.
And that's a famous one that they like to use. I bring it up because that's where I live. In this part of the world where we see coccidia mycosis, and eosinophilia is a non-specific thing that you might see.
But think about cocci, think about allergies, think about parasites. If you see elevated eosinophils, there's other things that can do it, but that's one of the things that can do it. But the one that you're probably going to see the most are these bands, segs, neutrophils, and that'll be elevated in pyogenic or bacterial infections.
And there's usually a range. So typically what you would see in terms of percent is maybe about 60% will be BANS and SEGS, maybe about 22 or so percent, and this won't add up to 100%, but around 20% or so for lymphocytes, about 5% for monocytes, maybe 2% to 4% for eosinophils. If you see a deviation from that, then you know that there is a simple line that is increased.
So if this lymphocytes all of a sudden shoot up, think about viruses. If this... segments go from 60 to 80 or 90, think about a pyogenic or bacterial infection.
If instead of 4% you're at 20%, start thinking about what we talked about, cocci, allergy, or parasites. So we talked about what's normal, we talked about watching the trend, we talked about the differential, let's talk about causes and what to do if the white count starts going up on you on a patient in the hospital. So in terms of causes, the big four that I want you to know are infection, steroids, cancer slash leukemia, or a catastrophic event. And these are kind of listed in order of the most common.
Let's talk about infection first. So typically with infection, you're gonna see something called a left shift. And what that means simply is that bands are basically released from the bone marrow and then they become segmented neutrophils, okay? Otherwise known as PMNs.
What happens is you see a very little bands and a lot of the lymph nodes are released. a lot of segs normally. And when you have an infection, the bands start to be released more and more.
And so you see the bands start to go up in circulation. They'll actually tell you how many bands there are. If you start to see bands in circulation, that's a very good indication that what you're dealing with with an elevated white count is an infection.
The things that you want to look for clinically, look for fever. That will also tell you that that's what it is that's going on. Look for signs of infection. The other thing to do is Ask the patient, do they have pain?
That's usually a sign that there's an infection somewhere. So look for corroborating evidence that there is an infection going on. If you can't find it, start to do diagnostic tests to confirm it. So things that might be able to do it, chest x-ray, get a urinalysis. You might even need to get a CT scan to look.
If the patient has a fever and is altered, by all means, get a lumbar puncture to rule out meningitis. The biggest infections are pneumonia, which you'll see on a chest x-ray, a urinary tract infection, which you'll see on a urinalysis. Look at their skin. See if they've got cellulitis somewhere.
Examine their belly. See if they're tender. Think about cholecystitis.
Think about diverticulitis. All of these things are going to cause an elevation in the white blood cell count. Okay, the other thing that you'll see is steroids. So a lot of time people will come in and they'll need steroids for either a COPD exacerbation or they'll need steroids for an asthma exacerbation.
And you'll put patients on steroids for whatever reason. What you'll notice almost invariably is the WBC count is going to go up. Now, why does the WBC count go up?
It goes up for three reasons. And this will help us decide and distinguish between why it might be an infection. Okay. The first reason is something called demargination. What does this mean?
Here's your vessel with the white blood cells in the middle of it. What you don't realize is that their white blood cells are already adhered to the wall. And so what happens is the steroids cause these cells to come into the center of the blood vessel. So when you draw the blood, you're going to get more of those white blood cells in your sample. That's demargination.
About 60% of the effect that we see with an elevated white count. is from demargination. Now the other thing that might cause this is delayed migration. So everybody knows that these white cells go out of the blood vessel and into the tissue. That's where they fight infections in the tissue.
Well if you delay that migration of cells, of white blood cells, into the tissue, they're going to be more likely to be in the blood vessel when you draw the blood and get the leukocytosis. And we see that about 30 percent of that effect is due to that. The last one that we see here is about 10% of the effect, and that is bands released from the bone marrow. But this is such a small proportion of the reason why the white blood cells go up, so small that in fact we can actually look at this situation and say that if you see the bands going up significantly, it's probably not from steroids, it's probably an infection.
And that if we see... all of the different white blood cells going up. For instance, we see the lymphocytes and the neutrophils and the monocytes, and they're all going up proportionately.
That's usually a result of demargination, and that's typically what we're gonna see in steroid use. So if you've got a patient who has pneumonia and you put them on steroids because they're having a COPD exacerbation because of the pneumonia and the white cells go up, but you don't see a left shift, you don't see bandemia, then you can probably chalk that up to steroids within reason, right? Steroids are only going to make the white blood cell go up, you know, maybe from 12 to 20 at most, okay?
If you start to see 30, 40, 50, then there's going to be a problem. Speaking of which, if we go back to infection on number one, there is a very famous infection that I would be remiss in mentioning that we see in patients, especially in the hospital, and that corollary is C. diff. I don't want you to miss that.
If you start to see white counts in the 30 to 40 to 50 and higher range, so these incredibly high white blood cells, something you have to think about is clostridium difficile colitis. And in this situation, you typically do imaging like a CT scan to look at the bowel wall and you'll see thickening of the colonic wall in that situation. Typically the treatment.
includes PO vancomycin, not IV vancomycin, but PO vancomycin, and either PO or IV flagyl. There are other treatments. There's even surgical treatments. So the earlier you catch this, the better. So think about C.
diff if you have a very, very high white count. Okay, so we talked about certain types of infection. We talked about steroids causing elevated white blood cell.
The other thing that can do this is if there is a leukemia. Of course, remember with leukemia and lymphomas, there's a problem with the production or the survival of these white blood cells. So in other words, there is some sort of gene that gets turned on, and these white blood cells start dividing rapidly, and so you're making a lot of these. Another potential reason why you could have leukemia or lymphoma is if the cell doesn't die and doesn't involute and just hangs around. So there's different variations on this.
Of course, you know that there is acute lymphocytic leukemia. There is chronic... lymphocytic leukemia. There is acute myelogenous leukemia, which is a really bad player.
And then there's chronic myelogenous leukemia. That's the one, the Philadelphia chromosome, et cetera. So all of these can do it. The thing that you must remember, or one of the things that you should remember, is something called LAP, or leukocyte alkaline phosphatase.
And this is the stuff inside the cells that is responsible for breaking down and killing bacteria. Well, in cancer cells, each cell has a lower amount of this leukocyte alkaline phosphatase. So in the old days, before we had flow cytometry and more genetic... ways of figuring out whether or not there was a leukemia or lymphoma, what they would do is check a LAP score, okay? And if there was a high leukocytosis but a low LAP score, that was indicative of cancer leukemia.
If the LAP score was elevated, that means that there was an appropriate amount of leukocyte alkaline phosphatase in these cells, and that probably wasn't it. So what should we look for? Again, if it's a lymphocytic leukemia, obviously we're going to see elevated amounts of lymphocytes. And so if you see a high white count and they're almost all lymphocytes, think about this as a diagnosis. If on the other hand, you see various different types of myelogenous type of cells, myelogenous meaning segmented neutrophils or eosinophils or monocytes, things of that nature, then that would be something along the lines of AML or even CML, depending.
So these are divided. Okay. What you really need is a peripheral smear.
and you need a pathologist to review the cells to see if they look atypical. If they look atypical, then you need to get even deeper, and you might even need a bone marrow biopsy done to evaluate for that. Okay, and then the last thing that we're going to talk about is catastrophic event.
So a catastrophic event like a myocardial infarction or a cardiac arrest or a massive pulmonary embolism is such a stress on the system, or even surgery could be a stress on the system. that this would cause a transient increase in the white count. So what you would see is a bump up very quickly and then the white count would come back down again as you were to track it. There are many other things that can cause leukocytosis that I have not included here. Even a cold shower can make your white count go up.
So think about these things as you look at your WBC on your CBC. Thanks for joining us.