Today’s episode of Talk EM is brought to you by the Emergency Medicine Institute. Now, the Emergency Medicine Institute stresses to train PAs and nurse practitioners working in emergency medicine to really increase their confidence and competence.
I think it’s really important if you’re in clinical practice as an advanced practitioner, you need to go to conferences that change your practice. There are way too many conferences out there that give you information, it’s good, but you don’t use it. It’s almost like they’re teaching over your head, throwing you literature and pie charts. What do you actually do when a patient is in front of you? How do you talk to your supervising doc? The Emergency Medicine Institute stresses clinical application, where you have measurable changes in your confidence and competence. They have a conference coming up in Sarasota in June of 2018, and then another conference in the Niagara Falls area in October of 2018, as well as an urgent care conference coming in Park City, Utah, in December of 2018.
We’re starting a series now on lab medicine. We have had a number of requests from APPs about how do we use lab medicine in our diagnostic tools in the emergency room and urgent care setting. That’s what we’re gonna start today. We’re gonna pretty much run through all of the major labs. Again, you can open up a textbook and be kind of overwhelmed. We’re gonna talk about clinical application, what’s considered the standard of care.
Now, my name is John Bielinski and have been a physician assistant for 20 years. My experience … Yeah, I’m an ER guy, I’m an ER urgent care guy, but I practiced pretty differently ’cause I worked in critical access and emergency medicine. I had to pretty much work by myself, take these labs and be able to communicate them to hospitals, intensivists, cardiologists. But also, the unique experience that I had was for five years I worked as a nocturnist covering hospitals, covering hospitals at night. So the DKAer that you admitted, I have to manage them on the floor. Part of my responsibilities as a nocturnist was covering the intensive care unit.
So I’ve had a really cool run for the last 20 years working intaking patients into the emergency room and seeing them super sick, the septic patient. Then admitting them to the floor, managing them on the floor. Then when they decompensate on the floor, or when they got too sick for the floor and they were put in the ICU, I got to manage them in the ICU. So at night, I didn’t have a doc always breathing down my back, and so I really had to get really good at using diagnostic tools and communicating that to doctor over the phone. I could probably do 10 podcasts just talking about the mistakes that I made, how I looked really silly. I wanna save you from that. These next series of podcasts are all gonna be about lab medicine, how to use them and how to be able to communicate them appropriately to people — your supervising doctor, your collaborating physician, consultants — in a way that has them respect your knowledge base.
So, today I just wanna talk about the CBC, but more basic than that is just the WBC, just the white blood cell count. So I just wanna talk about what does that really mean when it comes to clinical medicine. Now clearly you’re always looking at the context of the patient, and I don’t wanna get real basic on this podcast, but I wanna give you tools to have you talk the language that get the respect of the hospitals, the critical care doc. That’s gonna be the barometer here. When you talk, you’re not talking like a 101 level PA or nurse practitioner, you’re talking like a 5.01.
So, let’s just talk about the white blood cell count. Now first and foremost, as you guys all know, you have a basic CBC and you get the white blood cell count. Now that CBC typically is run through an analyzer and it spits out some numbers. It’s kinda like a blood guess where there’s a lot of numbers that don’t mean anything, but you need to know what the key numbers are. So when I look at a CBC, I wanna know what the total white count is, absolutely. Is it outside of a range of normal or lower than a range of normal? So normal white count is about 5,000 to 10,000, and the exact range isn’t relevant, but about 5,000 to 10,000 is reasonable.
So, when I’m working up a patient and I see that white blood cell count up, what does that tell me? Now, again, you’re gonna apply bayes theorem, and bayes theorem is the concept of pre-test probability. What are you looking for? If you have a geriatric patient from a nursing home with a fever, that white blood cell count is gonna be much more suggestive of infection. If you have someone with a kidney stone, that white cell count is gonna be more suggestive of a stress response.
Now this is really important. What drives that white blood cell count up? Now, you have to understand three adrenal hormones. Now the three adrenal hormones, the mnemonic I use is ACE, A-C-E. You have three major adrenal hormones, so you have aldosterone, cortisol, and epinephrine. All I wanna talk about right now is cortisol. Cortisol is your ultimate stress hormone, and if you think of it this way, it’s gonna help you clinically and it’s gonna help you when it comes to understanding the use of glucocorticoids. So when you use prednisone, decadron, Solu-Medrol, you’re really just using synthetic cortisol. Cool.
So, cortisol is your ultimate stress hormone, so when cortisol is high and when you get stressed out … Okay, if someone jumps out and scares you or if you’re going through a prolonged really stressful environment, your adrenal gland is gonna be working overtime. When your adrenal gland is working overtime, three things happen because it’s your stress hormone. Number one is cortisol is an antagonist to insulin. So, if I give you a shot of insulin, your blood sugar will go down. If I give you an antagonist to insulin, your blood sugar is gonna up. So if someone’s cortisol levels are high, their blood sugar is gonna go up. Just like if you give someone prednisone, their blood sugar is gonna go up because cortisol is an antagonist to insulin. You’ve gotta remember anytime you give someone a glucocorticoid, you’ve gotta expect their glucose to go up. That’s why they call it a glucocorticoid. Cool.
Second things that happen with a elevation of cortisol is it’s a potent anti-inflammatory. It lubricates your joints so they move better. If someone’s got arthritis, we could use prednisone because it will be a steroidal anti-inflammatory. Remember, you have non-steroidal anti-inflammatories and steroidal anti-inflammatories. Cortisol does that.
Last thing it does is when your body is stressed out, God’s saying, “Holy cow, I wanna give you optimal resources to fight off whatever your problem is.” That stimulates the bone marrow to shoot out white blood cells. When someone’s cortisol level is high, they’re gonna have a leukocytosis, they’re gonna have a white count. You know that anytime you give someone 125 of Solu-Medrol, they’re gonna get a bump in their white count.
If you’re listening to this podcast, and I sneak up on you wherever you’re sitting right now, and I have a hammer in my hand and I whack your right great toe. I break your toe. You’re gonna have a stress response, your adrenal gland is gonna shoot out some cortisol, you’re gonna get a 12,000, 14,000 white count. It’s a stress response. It’s not suggestive of an infection, it just tells me that there’s a stress response. Guys, I’ve never seen someone have acute coronary syndrome that didn’t have a white count or a kidney stone that didn’t have a white count. It’s not infectious, it’s a stress response. When someone has got a leukocytosis, you have to ask the question is it infectious or not. That’s gotta be the question that’s on your mind, it’s gotta be in your note.
If you’re working someone up for infection, what’s going to stack the deck to make you think yes, it’s really an infection. Well, what’s the patient’s chief complaint? Are they spitting up sputum, do they have dysuria, do they have back pain, do they have a fever? Ladies and gentleman, make sure that you’re really valid when it comes to your vital signs. Younger clinicians, they get vital signs from the nurse and think they’re gospel. They’re not gospel unless you check them yourself. So just make sure you have a valid temp. Is it an oral temp in a person that can’t tolerate an oral temp, like a demented patient who can’t close their lips around the probe, or a kid. Own your vital signs, rectal temp is the gold standard.
When you’re looking for an infection, I wanna know do they have a fever and do they look sick. Now, when you’re talking to a patient that can communicate to you … If you’re listening to this podcast, you know what it feels like when you’re coming down with a cold, that you just feel sick. I just don’t feel good. Well, that’s a sensation of malaise, and you wanna try to evoke that in your history. Do you feel like you’re getting sick? When you’re looking for someone with an infectious process, yes, you want fever, yes, you want chief complaint, but ask them, “Do you feel you’re coming down with a cold?” When they say, “Yeah, I just do,” that should make you think it’s an early infection. It’s a pretty good part of the history.
So, when I start looking for an infectious process, I always wanna think wind and water. You always wanna think is it pneumonia or a UTI, that’s really where the money is, so your brain is gonna go there. There’s five major body systems that I think about, wind and water, brain and belly, so do they have meningitis or something going on in their belly, and then their skin, make sure you roll them. You can have weird infectious processes, the big one I want you to think about is endocarditis. But the five big ones are gonna be wind and water, brain and belly, then skin.
Now, when you look at a CBC, yes, you get a total white blood cell count. Too many APPs think that’s it, “Oh, I got a white count of 18,000.” That ain’t it, that is not it. If you stop there, your thinking is very low caliber. I want really three numbers from you. Now, I wanna know total white blood cell count, but I also wanna know things about the differential. Now as you guys all know, there’s five different kinds of white blood cells. You have granulocytes and agranulocytes. Your major granulocytes: you have neutrophils, basophils, lymphocytes, monocytes, and eosinophils.
Now, neutrophils are like the Pac-Man, it eats bacteria, that’s what you should think about. Neutrophils dominate your white blood cells to the tune of about 75% to 85%. Beautiful, fine. Now, when that neutrophils count is high, that’s significant. When you’re trying to make the case that a patient’s got an infectious process, I just don’t want the white blood cell count, I’d like to hear the neutrophil count too.
“Hey, they’ve got a neutrophil count of 92%.” Beautiful, that helps me as a clinician. That helps you as a clinician.
Now, a lot of people think a high neutrophil count is a left shift. Guys, that is not accurate. It blows me away how many people at conferences seem to think that. That just tells me they have a high neutrophil count and it suggests a bacterial infection, it’s not an absolute, but it’s not a left shift. Now a left shift is immature neutrophils. Understand that left shift is a literal term and it came from laboratory technologists, because when they’re counting white blood cells manually under a microscope, they have a counter that they use their left hand to punch the keys. The button for bands are way on the left of the counter. So when they keep shifting their hand to the left side of the counter to push the “band” button, that’s literally what a left shift means. So a left shift means a high number of bands. I cannot stress this enough. I swear it, I preach it, so please hear me. Guys, a high band count is as sinister as a positive troponin. It means they’re sick, they’ve got an infectious process that’s about to really launch an attack.
So if you say, “Hey, I’ve got a patient with belly pain. They’ve got a 12,000 white count.” My visceral response is gonna be well that’s no big deal. But if you tell me they’ve got 22 bands, I’m gonna go, “Oh shit, this dude is sick.”
When you’re talking to a consultant about someone with an infectious process, a low end clinician will just say a white count of 18,000. A higher end clinician will say they have a white count of 18,000, 92% neutrophils, and four bands. Now a normal band count should be a couple percent, 2% to 4%, kind of like a reticulocyte count. A reticulocyte is an immature red blood cell, and that’s only elevated if someone’s losing blood either from blood loss or hemolysis. We’ll talk about that on the next podcast when we come to discussing red blood cells, hemoglobin, and hematocrit.
When you’re communicating about infectious process, I wanna know the total white count, neutrophils and bands. Now, be aware, if you have a leukopenic patient, when that white count is less than 5,000, that better make you pause. You’ve gotta ask why is that white blood cell count low, because overwhelming in sepsis can crash your white blood cells. There’s lots of things that can cause those white blood cells to be low, but the first thing I look at is are they in chemotherapy. That’s probably the most common in my clinical experience, they’re on chemo. When someone’s got a really low white count and they’re on chemo, you’ve really got at old records and you’ve gotta talk to the hematologist/oncologist.
When someone’s on chemotherapy and their labs are all wacky, get the hematologist named on the chart. Just say, “Hey doc, I’ve got a patient and they look pretty good, but they’ve got some funky labs. I just wanna run ’em by you. Yes, I checked their old labs. They’re pretty close, but while on chemotherapy I just wanna make sure you’re comfortable with this.”
If someone’s got a low white count, I wanna look at the other formed elements. The other formed elements are gonna be your red blood cells and platelets. So if someone’s leukopenic, anemic, and thrombocytopenic, everything is low, it tells me their bone marrow has shut down. Once again, the most common cause of that is chemotherapy, but it could be weirdness going on, bad stuff going on with the bone marrow like a malignancy.
When it comes to leukocytosis, I wanna look for infection. If it’s leukopenic, I wanna know why. You’ve gotta answer that question because again, if someone’s leukopenic, especially when their neutrophils are low, they’re a high risk for infection. At times when we would admit them to the hospital, we would put them on isolation precautions where we make sure we gown up and we don’t give them any diseases ’cause they’re really immunosuppressed.
Now, when we talk about a stress response, remember that if someone’s got a painful stimuli or some kind of stress, they’re gonna have elevated cortisol levels, therefore they’ll have a white count. I believe this to be true but I don’t have any evidence behind this. I believe the white blood cell count is the most sensitive cardiac enzyme. I believe it’s more sensitive than a myoglobin. So when someone has an acute occlusion of a corneal vessel, I believe the white blood cell count goes up before the myoglobin, but that’s just my experience taking care of hundreds of acute coronary syndromes, not just in the ER but on the floor covering telemetry units.
In summary, CBC is really one of the most essential basic labs. You’ll have a lot of board certified ER docs really put low stake, at least intellectually, in the white blood cell count. Why should you even check a white blood cell count when checking for belly pain because it doesn’t make a difference what we do, it’s more about the clinical exam. Intellectual ER docs will say that and they’ll have literature to back it up. I just don’t care about that. You’re not gonna assess a belly without a white count. Hospitals won’t tolerate that, surgeons won’t tolerate that, and I think even the ER docs that have been around for a while.
Yes, I think when they communicate about their hesitancy of relying too much on the white cell count, I think that’s literature-based and probably it’s true. But it’s kind of like orthostatic vital signs. If you look at literature on using that to look at volume status, it’s not really great. But orthostatic vital signs are really helpful in working up someone with potentially anemia or losing blood. Again, we’ll talk about that in the next podcast.
The white blood cell count is an essential part. You in your mind have got to categorize them as a stress response or infectious process and then work them up accordingly.
Thank-you for listening to this podcast. May I invite you to do me a couple favors? Like this podcast, share it with other people, make comments on it. Let us know that this information is working for you. As an educator, what drives me is that it makes a difference in other people’s lives. If this is working for you, when you let us know this, it makes me wanna work harder for you guys to serve you. So thank-you for listening, I will see you on the next podcast where we’ll talk about anemia and how to clinically think about the red blood cells, white blood cells, hemoglobin, and hematocrit. Have an awesome day, thank-you for listening to Talk EM.