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Course: Health and medicine > Unit 3
Lesson 8: Myocarditis and pericarditisCauses of pericarditis
Created by Raja Narayan.
Want to join the conversation?
- Wouldn't Heart Cancer in the pericardium also cause pericarditis?(6 votes)
- That's a good question Anna ! First, I assume that you are talking about heart tumor (the term "cancer" refers to a systemization of a tumoral process, be careful). In theory, the answer to your question is yes. In practice, primary cardiac tumor are very very rare. When it happen, there is a greater risk of extension to the electrical conduction system than of an inflammatory process. This is why the author of the video only mentioned the spread of another type of cancer to the pericardial space : most cardiac tumors are metastasis.(5 votes)
- Couldn't TB also cause Myocarditis? I mean TB is one of those few bacteria that can infect any part of the body.(1 vote)
- Tb of the heart or Cardiac tuberculosis is an extremely rare complication of lung TB. TB of the heart usually involves the endocardium/the inner layer of the heart. I could only find one case report of Tb causing myocarditis. http://www.ncbi.nlm.nih.gov/pubmed/11922029 So it is possible, but thankfully it is really rare.(5 votes)
- At minute9:00talking about uremic pericarditis, how could this type of pericarditis lead to pericardial effusion?(2 votes)
- I had a similar question so I researched it a bit. The best, most direct, answer I found here: https://www.uptodate.com/contents/pericarditis-in-renal-failure
Specifically:
"Uremic pericarditis — Uremic pericarditis results from inflammation of the visceral and parietal membranes of the pericardial sac. There is a correlation with the degree of azotemia (the blood urea nitrogen [BUN] is usually >60 mg/dL [22 mmol/L]), although the pathogenesis is poorly understood. Except in the case of systemic immune disorders (such as lupus erythematosus or scleroderma), there is no relationship with the underlying cause of renal failure.
So my take on this is that we don't fully know why.(2 votes)
- Why does the heart look larger then the liver bellow on the MRI animation?(1 vote)
- The MRI animation shows a saggital slice of the body. From the visibility of the thoracic aorta and what we can see of the vertebrae and sternum, this will be a little bit medial to the patient's left sternal edge. At that point, the MRI is slicing through a relatively small part of the liver, and it would get progressively bigger as we took slices closer to the patient's right hand side.(2 votes)
- I thought herpies was for... um male and female special places. NOT the circulatory system.
Help please. ()_()(1 vote)- It can cause problems with the circulatory system, and I believe it can be transferred through the circulatory system :) Just learned about this today!(1 vote)
- Doesn't heart surgery also cause trauma to the pericardium. Causing temporary pericarditis.(1 vote)
- yes, heart surgery can cause pericarditis(1 vote)
- Does uremia afffect other organs beside the pericardium?(1 vote)
- Yes! If uremia goes untreated, there can be many severe complications including bone diseases related to kidney failure, neurological complications (stroke and seizures), as well as cardiac arrest due to electrolyte abnormalities to name a few.(1 vote)
Video transcript
- [Voiceover] So, let's shift
over to pericarditis now, and let's start with
infectious causes there. It used to be that the Coxsackie virus also was the most common
cause of pericarditis, but recent studies have suggested that the number one cause of pericarditis, and this is again for the first world, so in developed countries, first world, may be from viruses,
so I'll write viruses. So, viruses such as what's
called cytomegalovirus. There's also herpes simplex virus, which is the herpes virus
you hear about a lot, and there's also the human
immunodeficiency virus or HIV, which you may have heard of as well. In the third world, however, we make a distinction for pericarditis. There's a different most
common cause out there, in the third world countries,
so the third world. Pericarditis, especially if it's advanced, is from a type of bacterium that you may have heard of before. It's called mycobacterium
tuberculae or TB. TB is the most common
cause of pericarditis in the third world, and I'll
write down here as a side note, this is especially true, so especially true for constrictive, constrictive pericarditis. And we'll talk more about what constrictive pericarditis means, but I think I've already touched on it. It's so much inflammation
of the pericardium that the heart isn't able to fill with an adequate amount of blood to pump to the rest of your body. So, TB is especially the cause
of constrictive pericarditis. So, let's skip on down here, and let's talk about some
non-infectious causes of inflammation of the pericardium, and I think one of the
most interesting ones is what's referred to as a post-myocardial, post-myocardial infarction pericarditis, post-myocardial infarction pericarditis. And maybe I'm throwing a lot
at you by saying that here, but just suffice it to say
a myocardial infarction is the exact same thing as a
heart attack, heart attack. Myocardial you might
recognize as myocardium, and infarction means a loss of blood flow leading to tissue death. So, a myocardial infarction,
or it might be called an MI, you may have heard that term, but this is also referred
to as Dressler's syndrome, Dressler's syndrome, and
Dressler's syndrome happens between something like two to three weeks. So, I'll write two to
three weeks to one month. I'll use or take advantage
of the terminology we just introduced
earlier, one month post-MI, or after a heart attack, where you have markers in the myocardium that are altered because of the ischemia or the loss of blood flow
released into the blood stream that causes the immune system
to create antibodies to it. And these antibodies, for some reason, will also attack the pericardium as well, resulting in post-myocardial
infarction pericarditis. All right, let's move on. Another important cause
of pericarditis could be radiation exposure, and this
isn't just one chest x-ray. This is having multiple
CAT scans of your chest over and over again over decades could cause radiation-induced
pericarditis, and the mechanism for this is what's called reactive fibrosis. Reactive fibrosis is what
results in pericarditis here. Another important cause is cancer. Not cancer of the pericardium,
but cancer elsewhere. Maybe you've got lung cancer,
or you've got breast cancer, and what happens is these cancers that are occurring elsewhere,
they spread to seed. So, seeding meaning they
start invading or populating. So, they seed the pericardial space. They seed the pericardial space, and they cause reactive
inflammatory changes because they are present there. Another important cause of pericarditis is just plain old trauma. Maybe you're in a motor vehicle collision, and it's a deceleration collision, where your car is stopped really abruptly because you've run into a wall, and then you fly forward, and your chest hits the
steering wheel so hard that the steering wheel is deformed. So, what that does then is, you end up getting what's
called a contusion. Contusion, which is just
a fancy word for a bruise. So, a contusion from
compression of the sternum. So, compression of the sternum, which is a bone in your chest, and I'll show you a
picture of it in a second. So, the sternum, which is
also known as your breastbone, on the pericardium. So, it's the sternum on the pericardium, and it compresses it and causes
damage to the pericardium, and when the immune system
tries to heal the pericardium, it ends up becoming inflamed temporarily, which causes pericarditis. So, I've got this nice animation here, and oh, this is so cool. This is an animated sagittal cardiac MRI. So, MRI meaning this is a
magnetic resonance image, and this is just a special
way of taking a look at what's happening in the chest. Sagittal meaning we've
cut this person in half, like if you karate chopped
them right through the head and down through the legs. What we're seeing here is
the right side of the heart, and this is the right
ventricle pumping blood through the pulmonary artery
and out towards the lungs, and this part that ends
abruptly, this is the aorta. This is the arch of the
aorta that goes into the thoracic aorta, if you
know those points of anatomy. If you don't, that's okay. But the aorta here is supposed to connect to the left ventricle, but we don't really see how it connects. It ends abruptly up here, because we've karate chopped between the right and the left ventricle. And so, that's why we're
only seeing this here. And the heart, of course, is just beating away blood into
the aorta very beautifully. The point of this image
I want to show you here is this bone that sits here. This is the sternum. This is the sternum that's right here, and this is the top part. You have the sternal
notch that's around here, and when you have a car accident, and the steering wheel compresses
against the sternum here, this will then be shifted backwards, and it'll hit against the pericardium. It'll hit against the pericardium and then compress the heart. And, in fact, in CPR or
cardiopulmonary resuscitation, when you compress on the chest,
you do chest compressions to artificially pump
blood out of the heart, into the aorta, and up into
your brain to oxygenate tissue while a person is not
beating their own heart, you also do the same thing, where you have the sternum press
up against the pericardium. That's another cause, potentially,
of pericarditis as well. So, this is a great image that we can see all of
this happening here, as normally it should
with the heart pumping, but realize the sternum sits right here and could compress against the heart in a traumatic way in an accident. So, let's be gone with this image. Go away. And let's keep talking right here. So, the last sort of subgroup of causes I want to talk about
that are non-infectious are metabolic causes of
pericarditis, metabolic causes, and there are two main ones
I want to talk about here. One is called hypothyroidism. You may have heard about the thyroid. The thyroid is an organ
that sits in your neck. Hypothyroidism is when this organ is not releasing much thyroid hormone. And thyroid hormone is responsible for increasing your metabolic rate,
increasing blood pressure, and a lot of other things in your body. When you have hypothyroidism, you don't have enough
of the thyroid hormone. So, you can get arrhythmias. Your skin can become course, because you have a slow metabolic rate. These people tend to gain weight as well. So, hypothyroidism, for some reason, will also cause pericarditis
that is best treated by replacing this missing thyroid hormone. Another important metabolic
cause of pericarditis is what's called uremia. Uremia is just the build up, so I'll write in parentheses here build up of nitrogenous waste. I'll just write N for
nitrogenous, nitrogenous waste, and it's the same type of waste your kidneys should be getting rid of. It's urea, if you've heard of
that type of waste product. It's a nitrogenous waste product, but in folks that are on dialysis with end-stage renal disease
or chronic kidney disease, their kidneys don't work. And so, they rely on dialysis to get rid of these waste products. If they skip a dialysis session, then maybe these nitrogenous
waste products can build up and irritate the pericardium, leading to what's called a
uremic, uremic pericarditis, which is something that's
treated with dialysis. You get rid of the nitrogenous waste, you get rid of the uremia, you
get rid of the pericarditis. So, in the next couple of videos, we're going to start talking
about how we can treat or diagnose myocarditis and pericarditis. For infectious causes, unless
it's a viral pericarditis, you'd probably use an antibiotic for a bacterial or a fungal or a protozoan cause of your myocarditis or pericarditis. For a non-infectious cause,
you would treat the cause. If it's something that you're
missing, like thyroid hormone, you would replace thyroid hormone. Some things you can't treat. You can't make trauma not happen, but it's important to understand what the cause of their disease was, to help guide the way you would treat it.