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Current time:0:00Total duration:8:51

Video transcript

so when we talk about what causes myocarditis myocarditis the inflammation of our heart muscle so myocarditis or pericarditis peri carditis inflammation of the outside lining of our heart we can think about two main causes or etiology x' it can be either of an infectious cause infectious meaning a microorganism like a bacterium or a virus or a fungus or something like that or it could be non-infectious non-infectious pretty intuitive right but from here we'll make some other distinctions about what we mean when we say non infections that's not as obvious as what I'm putting here so it's either infectious or non infectious and I'll talk about the main causes that fall under each of these categories and we'll start up here with myocarditis and in fact the number one or the most common cause of myocarditis in and I'll just write here the first world so the most common cause in the first world or the developed world's is a virus say virus and if you want to know the detail this virus is specifically called the Coxsackie virus Coxsackie or sometimes it's called Coxsackie verde but the Coxsackie virus is the most common cause of myocarditis in first world countries and for some reason medical professionals like to make the distinction about the most common cause in South America South America because it's an interesting sort of pathogen or interesting microorganism or so let's say for instance you just came back from watching a couple of soccer games in Brazil maybe and you've got this persistent chest pain and we do a couple of tests and we realize that there's an abnormal rhythm in your heart and so over time you find out that this person is infected with a proto ZOA in a protozoan which is a different class of microorganism from a virus and malaria is a type of protozoan but it's not the one I'm talking about here the specific protozoan that's involved with myocarditis from South America is known as trapano so trip and no soma Trypanosoma cruzi Trypanosoma cruzi and maybe you know it better by its disease name this is sha s disease Chagas disease and Jacques disease does not only involve myocarditis but you also get an infection of the esophagus and other parts of your body so it's this constellation of signs that would lead physicians to start thinking that maybe it's Jacques disease instead of a typical viral myocarditis that we commonly see in the States and then a final infectious cause of myocarditis I should mention here I'll just write this as an important cause an important cause of myocarditis and this is a type of bacterium this is a bacterium and the specific genus and species of this bacterium is called Borrelia with two R's Borrelia and then this species name is a lot of fun to pronounce Berg burgdorferi Borrelia burgdorferi which you may more readily recognize as the disease lyme disease especially if you're from Lyme Connecticut where it was first described so Lyme disease is also something that can lead to myocarditis but mind you this is advanced Lyme disease early on you'd get more of the skin signs that are classically associated with that and some arthritis but myocarditis can eventually occur if you have what's called chronic Lyme disease so let's skip on down here to our non-infectious causes the first one I'd want to mention for myocarditis is idiopathic idiopathic and what does that mean exactly well the way I remember it is that an idiopathic cause is one that makes us feel like idiots because we can't actually figure out what it is so idiopathic means the cause of a disease that is unknown so I'll write in parenthesis here a question mark so idiopathic myocarditis is myocarditis of an unknown origin but because a virus is so overwhelmingly the likely cause of myocarditis some physicians will just chalk up idiopathic myocarditis to just be likely viral in origin so it's likely a viral myocarditis in fact some literature suggests that about 50% of all myocarditis is idiopathic and that most likely just is viral all right so let's move on to our next cause right here and this is a disorder it's an immune system disorder that's called rheumatic rheumatic fever rheumatic fever and rheumatic fever is caused by a streptococcal infection so I'll write a strep infection so this could be something like strep throat so strep infection or it could also be what's called streptococcus emia which just means a blood infection of streptococcus throughout your bloodstream so this strep infection will then end up causing the immune system so the immune system to make antibodies and I'll abbreviate antibody is just a B antibodies that attack that end up attacking your myocardium and so rheumatic fever is a big deal because if it's not caught this could potentially then be a life-threatening disorder that attacks the heart muscle and this actually is something that we are more concerned about in developing countries where we don't always treat a sore throat strep infection in the States if you have a sore throat that lasts long enough people are more likely to go to the doctor and get an antibiotic for that so other than that there's also a couple of drugs or substances that you can take that are what's called cardio cardio toxic cardiotoxic and as the term suggests that means that they're no good for the heart and there are a bunch of things that are cardiotoxic such as cocaine which honestly is no good for any part of the body if you abuse alcohol if you take in too much alcohol in a short period of time or over years and years of consumption that can be cardiotoxic there's also carbon monoxide poisoning which is something to be concerned about if you fall asleep in a garage with a car on carbon monoxide poisoning can lead to myocarditis and then certain chemo drugs chemo drugs so chemotherapy drugs that were used more commonly in the past can also cause myocarditis and I'll give you an example of one of them it's called doxo doxorubicin doxorubicin is known to be associated with myocarditis in some people but not all the time so these are just some of the drugs or substances that you can take that can be myocardial toxic if you want to be that specific but then finally there are also some systemic diseases so all right systemic diseases that can target the myocardium to cause inflammation there these include things like lupus which is a disorder where you make a bunch of antibodies against parts of your body that should not be attacked by the immune system but are and so that can cause myocarditis there's another disorder that's called sarcoidosis sarcoidosis where you have granulation tissue or inflammation tissue it's another term for inflammation granulation tissue setting down in the myocardium causing inflammation there and there's another disorder that's called systemic sclerosis or scleroderma all right scleroderma derma scleroderma right here which is when you have the connective tissue protein collagen being made in tissues that it shouldn't be made that commonly so sometimes you'll see an excess amount of collagen be made in the skin making your skin very tight sometimes it's made around the esophagus making it difficult to swallow and sure enough scleroderma scleroderma can also deposit a bunch of collagen in your myocardium to cause myocarditis as well