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Current time:0:00Total duration:12:48

Diagnosis of myocarditis and pericarditis (part 1)

Video transcript

so this video we're going to talk about how to diagnose myocarditis and pericarditis both diseases are somewhat similar in terms of where they happen and the fact that they're both inflammatory processes so a lot of the labs will talk about our indicative of both disorders but as we talked about more and more invasive tests that we can do to determine what's going on we'll see when we can discriminate and say this is myocarditis or this is pericarditis so let's start by talking about certain labs that you can order or things that you can analyze in our blood so let's say I've got this vial right here so there's a green top on this vial and here's the rest of the vial as it goes down here curves right back up and this guy is going to be filled with blood so there are a couple of things we can look at first of all there's the white blood cell count the white blood cell count and this isn't very specific it's increased in all types of inflammation so this could be inflammation from an infection it could be from an autoimmune disorder or if you're in a car accident a traumatic injury can also cause inflammation and an increase in your white blood cell count other than that you can also look at what's referred to as the erythrocyte I'll write this out this is the erythrocyte which you might recognize as the term for a red blood cell the erythrocyte sedimentation sedimentation is the process of blood or some fluid resting after it's been spun in a vial if sediments down so Ruth recite sedimentation rate so that's also referred to as the ESR the erythrocyte sedimentation rate the ESR and this has the same feature as being increased in inflammation as well so it's not specific to myocarditis or pericarditis versus other types of inflammatory processes there's also another marker we look for that's called c-reactive protein C reactive protein which is a protein that's made in the liver so I'll just write CRP that's often which you see it's called on a lab results sheet CRP and it's produced in the liver and it's also nonspecific this is also increased in inflammation increased in inflammation but we're narrowing down now let's get to more specific labs we can order what's called a creatine creatine phosphokinase level so a creatine phosphokinase level it's an enzyme right that's what a anything that ends in ace refers to creatine phosphokinase it's a CPK level and we're looking to see how much of this enzyme or this protein has leaked into our bloodstream and this is more specific because it's increased in our blood stream when there is damage to the heart brain or some muscle heart brain or muscle damage heart brain or muscle damage which means that if a person has myocarditis or if a person has just run a marathon you wouldn't be able to tell the difference just by looking at the CPK level they'd both be elevated but perhaps one of the more specific labs are the most specific lab that you can order is what's called the troponin level a troponin level which you might recognize as a protein that's responsible for contraction of muscle and it's present in the heart if you look at certain isomers of it but a troponin level will be elevated when there is heart tissue damage heart tissue damage so it's very specific for some cardiac process and this is one of the first labs we'll ask for when we suspect someone's having a myocardial infarction or an MI or a heart attack and this also can help us distinguish between myocarditis and pericarditis because you can get an elevated troponin level with acute or fairly early myocarditis so acute or fairly early myocarditis because you have damage to the myocardium the heart muscle which is where you store your troponin or you might see it in late relatively later pericarditis because the pericardium is not a muscle it lines the muscular layer of your heart and so if the pericardium is compressing on the heart perhaps you'll have troponin leak from the heart eventually but that'll have to be late pericarditis or more advanced pericarditis all right so these are all the labs that we would order let's move on and let's talk about how we can use an electro and electro cardiogram an electrocardiogram which if you were to abbreviate we would call it an ECG but because this is something more of a German term we call it oftentimes an EKG in EKG which you may have heard of more commonly an EKG could be helpful in diagnosing between whether a patient has myocarditis or pericarditis and I think I showed you this animation earlier where you can see here that there's an initiation of a signal that comes down and is spread downwards there and then comes back up through this myocardial wall and as this is happening there's a signal here that's being made and it starts with AP wave a Q R and then it's gone s and a T wave I'll draw that again in a minute but these all happen first the P wave as you have contraction of your atria so see when this pumps here we'll have the P there then you have this QRS complex call together when the ventricle contracts so as you see now the red was where the ventricle was contracting and then this T wave at the end is when it relaxes the ventricle relaxes and you can see the redness going back upwards signifying that the ventricle is relaxing during this time so this is what we look at in an EKG this is the electrical signal of the heart that we're studying by putting some leads or stickers on someone's chest so let's get rid of this thing we see here that an EKG helps us to study the electrical signal in the heart so the electrical signal of the heart and we have different leads or different I guess snapshots of the heart based on which direction we're looking at it from and so a normal EKG would be flat like this and then we would have a bump here this is what's referred to as a p-wave this is where your atria would contract and then there's a cue wave down here so there's a cue where there's a spike down and then the spike up right after is referred to as the R wave the R and then we have this spike down again and then that's the S wave and we usually refer to this together as the QRS complex and then we have a flat line here before we get another wave and this is our T wave so this segment in between is known as the ST segment I know that's a lot to mention right now I'm not expecting you to memorize everything about EKGs but these are the letters I'm about to refer to and we see some fairly classic or characteristic changes with myocarditis versus pericarditis so first I have this EKG over here that we're trying to figure out and this is actually going to be classic for myocarditis so this is myocarditis because with myocarditis always C is what's referred to as tachycardia and it's specially called sinus tachycardia when we're looking at a EKG because we have the correct rhythm we have the correct rhythm but our rate is a little fast and as you might recognize we've got our and this lead right here as we follow through for this guy we have our P right here there's the QRS that's squeezed in there and we've got the T right there before we start up with another P which is right here and so we've got all of the right waveforms that we need kind of shaped as they're supposed to but this is kind of a fast rate to have and so we've got sinus tachycardia with myocarditis here in this patient now another EKG we could look at here has some more specific changes that we can note and this is what's associated with pericarditis pericarditis and in pericarditis what you'll see is diffuse diffuse ST segment elevation ST segment and I think I told you in our perfect EKG drawing that I did over here because this is so perfect this ST segment here is flat if you look for the ST segment down here notice that this is our baseline but the ST segment is elevated right there and if we look at the other leads as well so this is flat on this dark red line the ST segment is elevated right there as well and so it's elevated here so it's elevated in all of these leads that we're looking at and these are flipped over but this one this lead right here shows that we've got an elevation as well above this solid red line and so we've got ST segment elevation so I'll write an increase right there because it rises up and when you see this for pericarditis its plastic and you can actually diagnose it straight from here and you don't need to move forward we can start treating right away for myocarditis sinus tachycardia is not a very characteristic finding on EKG so we'd have to do other tests so let's move forward and talk about some other tests another test that we can order to look at the function of the heart is something that's referred to as an echo cardiogram an echo cardiogram and maybe the echo part of it gives it away but we call this an echo for short the echo part refers to the fact that we are only using sound waves or ultrasound to look at the heart so I'll make these important notes here we're using sound waves to look at the heart so sound waves which is great because we're using no radiation which you might recall is actually a cause of pericarditis you'd want to avoid using radiation and the other thing about it is that we study we study the hearts function so that we study the function of the heart with an echocardiogram because we're looking at an actual moving image and this can help us differentiate between a patient that may have myocarditis myocarditis or pericarditis as we'll see in these videos right here now this is an echocardiogram of the heart and as we're looking at these this is a four chamber view right here this is the right atrium the right ventricle the left atrium and the left ventricle and this is a patient actually that has mild myocarditis and the way you can diagnose that or tell is if you look at the right ventricle here look at how much compression you have here at this part this is a really acute angle that closes whenever the heart beats relative to that over here in the left ventricle we say that this is hypo kinetic hypokinetic because it's not contracting the way it should and so this is one of the things you get with myocarditis where you have a dilation of the chamber and an ineffective ventricle that should be pumping blood out to the rest of the body now here's an echocardiogram at a different cut of the heart and if we press play you'll notice up here that there's a lot of fluid that's sitting between the heart and the pericardium so that's the pericardium that's sitting up here and this is because we have what's referred to as a pericardial effusion it's an unusually large amount of fluid that's sitting in the pericardial space and it's compressing the heart it's preventing it from beating how it's supposed to it's preventing it from filling with as much blood as it would like to to pump out to the rest of the body and this could be dangerous because then you get hypotension or low blood pressure and other adverse effects that are associated with it here