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What is pneumonia?

Pneumonia is a medical condition where lung tissue becomes inflamed, usually caused by a virus or bacteria. Learn how shortness of breath, cough, and fever are common symptoms of this condition and why they occur in pneumonia. Created by Jannah George.

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  • leaf green style avatar for user Sam
    How does a common cold contribute to the development of pneumonia?
    (10 votes)
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  • purple pi teal style avatar for user Pi
    What's the difference between pulmonary edema and pneumonia? The both get fluid in the lungs and have pretty similar symptoms. They both can create so much fluid that they can reach your alveoli and kill you. That's what made the year 1918-1919 so deadly. The Spanish Flu killed a lot of people. Flu and pneumonia are a deadly combination. But what is the difference between them?
    (4 votes)
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  • leafers tree style avatar for user phoenixwrbird
    I still don't get how the fluid inside the alveoli is caused by the body's response to make inflammation. Can someone clarify it for me?
    (2 votes)
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  • piceratops seed style avatar for user Danni Palmer
    Hi,

    How does pneumonia trigger an inflammatory response on a cellular level?
    (1 vote)
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    • male robot hal style avatar for user Arkad
      Invasion of pulmonary alveoli by pathogenic microorganisms, in particular their endotoxins, causes mast cells to degranulate and release histamine and prostaglandin into the infected area. This is the start of the inflammatory response of the innate immune system as a response to the infection.
      (2 votes)
  • blobby green style avatar for user arvindraaj123
    you said the fluid accumulation is due to infected fluid from lung tissue. so there is not exudation ?
    (1 vote)
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  • aqualine ultimate style avatar for user veliz.dylan
    can the pueumonia cause pain
    (2 votes)
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  • leafers seed style avatar for user Antoine Levesque
    Does sticking a tube down someone's throat to help them breath damage the epiglottis?
    (1 vote)
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  • leafers sapling style avatar for user peliquack
    How can the infection of pneumonia cause in the air sacs? That doesn't really make sense.
    (2 votes)
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  • male robot hal style avatar for user Lord Chungus
    So in reference to the Spanish Flu (or the Influenza Outbreak in 1918-1919), was there really no cure for that type of Influenza? Did the virus mutate over and over again in both the trenches and people until it was almost impossible to cure? If so, what would happen if it popped up today? These are the things that I fear the most, an incurable disease the spreads like wildfire.
    (1 vote)
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  • duskpin ultimate style avatar for user Haniel
    what are some of the causes?
    (1 vote)
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Video transcript

Voiceover: When you hear the term pneumonia, I think that most of us think about lung infection, but not much else besides that. Pneumonia really is a little bit more than just a lung infection, really in relation to where it is. As we're looking at this image here I want to focus on the lungs that I've drawn out. We know that we have a right and a left lung. Our right lung, I'm just going to draw out some lobes here, we know that we've got three lobes in our right lung, so we have an upper, a middle, and a lower. In our left we've got two. We know that we have an airway, so our main airway. Now don't focus on this yellow line yet. Just focus on our main airway. We know that we breathe in air, and that air is going to travel down through these smaller branches, these branches that branch off. At the end of our airway, we have these little grape-like sacs. I'm just going to draw a couple just right here so we can see. These little grape-like sacs are actually air sacs, and we call those aveoli. The alveoli is really important because that's where the gas exchange happens. This is where ultimately the oxygen is going to end up, and where we'll pick up carbon dioxide to exhale out. Why is this important? When we talk about pneumonia, the pneumonia, the infection, is actually in these air sacs. What I'm doing is I'm drawing these sacs as if we could blow them up millions and millions of times, because they're actually very, very tiny. We have millions of them everywhere at the end of our airways. So if we could blow them up, they'd look something like this. Now right underneath it, I'm going to just keep drawing the kind of structure that we can expect that we'll see. We have air sacs I've drawn. Right underneath our air sacs we have tiny blood vessels that run beneath them and all around them. In between our air sacs, we just have some lung tissue. I'll just make that this brown color, make some lines to represent our lung tissue. So when we say that a person has pneumonia, the pneumonia infection is actually inside of these air sacs, and this is where the pneumonia is. Now any time that there's an infection or injury in the body, the body's response at that site, is to cause inflammation. That means that the tissue, that alveolar tissue Is going to inflame, and it's going to leak fluid. That fluid I'm making green, and I'm filling up the alveoli with this green fluid to represent the infection. It's going to leak out infected fluid into this air sac. Now, why is this a problem? Remember, we're breathing in air. Let's come over here and make this blue. Let's say that here's my air. I'm just going to travel down some blue air. I'm breathing that down. I'm breathing that down. I'm breathing that down. It's coming all the way down to our alveoli, because this is where I want to drop off the oxygen so I can breathe and ultimately get the oxygen into my capillaries, because that's what we need. The problem is that I have this block. I have this infectious fluid that's blocking that absorption of oxygen, and it's going to block the exhalation of carbon dioxide as well. That's the problem with pneumonia. It's taking up air space. As you can see, if this person had pneumonia, and let's go ahead and even draw it on our smaller grid, let's shade in some green into our alveoli here. If this person had pneumonia, what will we expect to see in them? We can see that we have our air sacs being occupied with this infectious material. Think about how that's going to affect their breathing. One of the things that we're going to see is dyspnea, which really is a fancy term for difficulty breathing. The problem that we're having really is shortness of breath. I'll just put short, short of breath. That's because, looking at our image, we see that we're not able to have that gas exchange. We can't get that oxygen into our space, because it's being blocked by something else. They're going to be experiencing chest pain as well. We know that's secondary to the inflammation that's happening at the alveolar level. We have pain receptors in our chest, so we're going to feel that. How about cough? Thinking about all that fluid in our air sacs, what do you think the body is going to try to do? It's definitely going to try to cough. That's the mechanism that our body has. It's going to try to cough to squeeze out and force out that fluid out of the airways to clear it, so we have room to breathe. We keep talking about infection. With infection you can expect to see a fever. That could be low grade, or that could be high grade. How does this happen? How do we get a pneumonia infectioand? There's really two ways. It can be from organisms, just that we get out in the community, or it can be from other ways that might not fit into that category. For the first one, I want you to think about organisms. I'm going to come over to this shoulder. I'm going to draw in a circle. That's going to represent my bacteria. I'm going to draw in a little viral illustration to represent a virus. Bacteria and viruses are certainly the most common causes of pneumonia. The good thing is that we have vaccines to combat two of the biggest culprits, which would be our Streptococcus pneumoniae, that's our bacteria, and the flu virus. These are our big, big offenders that cause pneumonia infections. Now when we pick up an organism, like a bacteria or a virus, and we can also get fungi and mycoplasmas as well, we call this community acquired. I'm going to write that here. Community-acquired pneumonia. When I say pick up, I mean just in our everyday activities. Community, you're thinking about people. Think about work or school, or you're out doing leisure activities. Because you're surrounded by people, and if you picked up an organism from somebody that was ill, we would call that community-acquired pneumonia. Just as we have air, we know that the transmission of air into our lungs, if we get a bacteria that enters our airway, it's going to travel down, and it's going to cause this infection. We said we would talk about other ways. Something that falls under our other way would be ventilator-assisted or ventilator-acquired pneumonia. I'm going to write that here, ventilator-acquired pneumonia. Make my D better, pneumonia. If someone's on a ventilator, we know that they're connected to a tube that's delivering oxygen to them. Let's come over here, and actually just erase away my little air symbol that I made earlier. That way we can make room for our tube. I'm just going to put it down to here. In this orange color, let's draw in this tube. We know the tube is inserted through the mouth or through the nose, and then it's guided down into the airway. It'll end about here. This tube is going to be delivering oxygen to this patient. On the outside, this tube is actually connected to a device. I'm going to write O2 here, because we know that's doing the work of breathing for them. Well, what's a problem with this? We know that because it's a direct route from the outside to the inside, that things like bacteria, viruses, other harmful organisms can actually get inside of the tube, can grow, and cause a pneumonia infection. Another way that we can get pneumonia that doesn't quite fit under our community acquired, or ventilator acquired would be aspiration. Aspiration means to breathe in. In this case, we would be breathing in something into the lungs that shouldn't be there. Let's get rid of our tube, so we can visualize aspiration. I want you to really think about patients that are at greatest risk for this, like patients that have been experiencing vomiting, for instance. We could aspirate vomit into our lungs. If we take a look at that yellow object that I said don't focus on that earlier, take a look at that now and see how it's moving. This yellow object is our epiglottis. Our epiglottis really directs traffic. We know that we have one main tube, but this tube actually is split into two. One route's going to go to the stomach, and one route's going to go to our lungs. Let me leave that open for a second and let's see the difference. In blue, here, this is going to be our direct route to our lungs. Then in green, here, this would be our route to our stomach. I'll just keep that going down, like it's going to our stomach. In the event that our epiglottis is open, that means that something can get inside of our airway. In this case, we talked about vomit. If somebody was vomiting, our epiglottis is open, we can actually aspirate the vomit into our lungs. Because our lungs are a sterile environment, anything that gets in there that's carrying bacteria is a danger to us, because it can make us very sick. The same thing can happen with somebody that is eating and accidentally aspirates food into their lungs.