Pericarditis and pericardial effusions – causes, symptoms, diagnosis, treatment, pathology

Pericarditis and pericardial effusions – causes, symptoms, diagnosis, treatment, pathology


Learning medicine is hard work! Osmosis makes it easy. It takes your lectures and notes to create
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much more. Try it free today! With pericarditis, “peri” means “around,”
card means “the heart”, and itis means “inflamed”. So pericarditis means the pericardial layer
of tissue that covers the heart has inflammation. People who develop pericarditis are also at
risk of also developing a pericardial effusion – that’s when the inflammation causes fluid
to accumulate around the heart. The pericardium is a pouch or cavity that
the heart sits inside of. The outer layer of this pouch is the fibrous
pericardium and it helps keep the heart in place within the chest cavity. The inner layer of the pouch is the serous
pericardium that includes the pericardial cavity, and is filled with a small amount
of fluid that lets the heart slip around as it beats. The cells of the serous pericardium secrete
and reabsorb the fluid, so usually there’s no more than 50 milliliters of fluid in the
pericardial cavity at one time – that’s about as much as a shot glass. Now, the cause of acute pericarditis is usually
idiopathic, meaning that we don’t know what causes it. Most of these are thought to be related to
viral infections, like Coxsackie B virus. Another cause is Dressler syndrome which occurs
several weeks after a myocardial infarction, or heart attack. Basically, when heart cells die in a myocardial
infarction, it leads to massive inflammation that also involves the serous pericardium. Another cause of pericarditis, called uremic
pericarditis, is when blood levels of urea, a nitrogen waste product, get really high
usually due to kidney problems. The high levels of urea irritate the serous
pericardium, making it secrete a thick pericardial fluid that’s full of fibrin strands and
white blood cells. This gives the wall of the serous pericardium
a “buttered bread” appearance. Pericarditis can also be seen in autoimmune
diseases, like rheumatoid arthritis, scleroderma, or systemic lupus erythematosus, because the
immune system attacks its own tissues, including the pericardium. Other causes of pericarditis include cancers
like lung cancer and lymphoma, radiation therapy in the chest, and even medications like penicillin,
and certain anticonvulsants. Regardless of the cause, inflammation in the
pericardium means that fluid as well as immune cells start moving from tiny blood vessels
in the fibrous and serous pericardium into the tissue or interstitium of those layers,
making the layer itself a bit thicker and more boggy – think of how a piece of dry flat
pasta gets cooked and thickens up as it soaks up fluid. Now, a pericardial effusion can also develop. That’s when pericardial fluid begins to
pool in the pericardial space, because the serous pericardium can’t remove it as quickly
as it comes in. If a lot of fluid starts to collect in the
pericardial space – in other words, if that pericardial effusion gets really big, then
it can start putting pressure on the heart itself, preventing it from fully stretching
out or relaxing between contractions. This can lead to tamponade physiology which
is where the cardiac chambers can’t fill with blood properly, causing a decrease in
cardiac output – which can be a medical emergency. When the inflammation persists, immune cells
can initiate fibrosis of the serous pericardium which can produce an inelastic shell around
the heart making it hard for the ventricles to expand -it’s like the heart is wrapped
by a boa constrictor. This is called constrictive pericarditis. Over time, it becomes harder for the heart
to relax or expand, and the stroke volume – the amount of blood the heart squirts out
with each heartbeat goes down, and to compensate the heart rate goes up. This is similar to tamponade physiology but
happens more gradually and is a result of a change in the composition of the serous
pericardium, rather than a fluid collection around the serous pericardium. The main symptoms of pericarditis are fever
and chest pain that worsens with deep breathing, but improves with sitting up and leaning forward. Larger pericardial effusions, those over 100ml
of fluid, can cause diminished heart sounds, and can even diminish cardiac output leading
to shortness of breath, low blood pressure, and lightheadedness. There are a few ways to diagnose pericarditis
and pericardial effusions. First, when the thickened layers of the pericardium
rub up against each other – it creates a friction rub which can be heard on auscultation. It sounds like two pieces of leather rubbing
against each other. Next, on an electrocardiogram, there are a
few changes that you can expect to see. In the first couple days to weeks, there can
be ST segment elevations and PR segment depressions. After that, the T waves tend to flatten and
then becomes inverted over a few weeks, and then eventually the ECG returns back to normal. On an ECG, pericardial effusions, especially
large ones, can show low QRS complex voltage or electrical alternans, which is where the
QRS complexes have different heights, as a result of the heart swinging back and forth
in a pool of pericardial fluid. On an X-ray of a heart with a large pericardial
effusion, you can see a silhouette that pools to the bottom of the heart and gives a classic
“water bottle” sign. On an echocardiogram, a pericardial effusion
makes the heart looks like it’s dancing within the pericardium, whereas constrictive
pericarditis shows the stiff serous pericardium restricting the heart’s movement. In terms of treatment, the main goal is to
relieve pain with analgesic medication, and to treat the underlying cause of inflammation. Colchicine, a medication that inhibits neutrophil
migration, is also used to decrease the likelihood of recurrent pericarditis. If there’s a severe pericardial effusion,
a pericardiocentesis can be done by inserting a needle into the pericardial cavity and draining
the excess fluid. Constrictive pericarditis may require pericardiectomy
which is a surgical removal of the pericardium. Okay, let’s recap – acute pericarditis is
usually caused by idiopathic causes, viruses, or after a myocardial infarction. It usually results in a friction rub, as well
as ECG changes like ST elevation and PR depression, followed by T wave flattening and inversion. Pericardial effusions typically lead to low
QRS voltages or electrical alternans, and can be seen on an echocardiogram. Constrictive pericarditis typically results
from fibrin deposition in the serous pericardium and it prevents the heart from fully relaxing.

18 comments

  1. You could have mentioned that the bread and butter heart is called `cor villosum` – nevertheless great video! Always a pleasure to watch!

  2. I have this. Im reading and seeing acute paracarditis may last 6 weeks (if I'm lucky) my question is, once it goes away does it come back ? Am I susceptible in the future ?

  3. I was worried that I have this, as have had an undiagnosed heart condition since two months ago, where I have massive night sweats, heart pain (which pulsates with every heartbeat), crazy headaches and dizziness. It turns out I have had a massive, sudden increase in blood pressure, for unknown reasons. I’m also suffering from reactive arthritis due to an infection some time ago. But as I understand the video above, pericarditis would result in LOWER blood pressure, not higher, correct? And thus it would not apply in my case? If anyone has any suggestions to why someone, like me, who recently only had 120/80 until as late as a half a year ago, and now suddenly has 165/100 (and higher when pulse is higher, it peaked at 200/120 when I did a recent test), let me know as my doctor has no clue…

  4. Hemorrhagic pericarditis, caseous pericarditis, chronic or healed pericarditis, adhesive mediastinal pericarditis?? Didn't explain any of these.

  5. Yo they need to find a way to cure this bullshit. I have this and it’s not fair. People from all over the world to horrible things to there body and they are fine. And me who plays basket ball and super active and in good shape got this…

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