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Pneumonia vs. pneumonitis

Pneumonitis is a term used to describe inflammation of the lung tissues without the presence of an infection, whereas pneumonia is inflammation caused by an infection. Learn what the symptoms of pneumonitis are, and why pneumonitis is more common with bird handlers, farmers, and people who regularly use humidifiers. Created by Jannah George.

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Video transcript

Voiceover: Depending on who you speak to, the term pneumonia and the term pneumonitis can be used synomonously, meaning that they can often mean the same thing. What I'm gonna do - and you see me drawing here - I'm just going to draw a set of lungs and we're gonna discuss what the differences are between the two. You see me just making the main airways, and now I'm just drawing off our bronchioles, which are our smaller airways. We know at the bottom of our airways, we have these air sacs. Let's see if I can pick a color for our air sacs. I'll make this a light color. We know that these air sacs are called our alveoli. I'm gonna put some on my right, and now my left lung. I'm making them like little grapes. Let's say that this side, this is gonna be my pneumonia. This side, that's gonna be my pneumonitis. When we're talking about pneumonia, we really are referring to an infection. It's an infection secondary to something that's organic, so an organism, meaning either a virus, or a bacteria, or a mycoplasma, or maybe it was pertussis. I'll just put these here to remember. Here's my virus, so I could've gotten a pneumonia infection because I had a virus. Maybe I got a pneumonial infection because I had a bacteria, right? This is so we remember what we're talking about. Let's make that circle a bacteria. Maybe I got it because I had a mycoplasma infection, so that would be my mycoplasma. When we say pneumonia, we're talking about an infection. When we're talking about pneumonitis, we really reserve that term when we're just referring to inflammation without the presence of infection. However, the tricky part is it doesn't mean that you can't get pneumonitis secondary to an infection, but I'll explain that in a minute. Let's just stick to pneumonia for one second. We said that we have an infection here. As a result of this infection, it's going to cause infiltrate. Let me get a color that's bright yellow so we can see. That works better. It's gonna cause infiltrate in the alveolar cavity. That means in our airspace, right? We're gonna have fluid consolidation. It's gonna be infectious fluid, so it'll be pus-like. That's secondary to the infection, because it causes inflammation, and that inflammation's gonna cause some leaking. That leaking's gonna be infected because we know it was caused by an organism. You see me coloring that in. In this pneumonia, you see i have my alveolar, and this alveolar, and this alveolar, and all of these together, of course, are alveoli. They're all filled with this infectious materials, this infectious liquid. so this is pneumonia. With pneumonitis, if we scoop over here and look at pneumonitis, the issue is not that it is an infection. It's that it is inflammation. Actually, I'm gonna make this a dark color. Our alevolar walls become inflamed. Now we have this inflammatory response that's happening in our alveoli, so it's becoming inflamed. So, I just color that in a little bit darker. Now that we see the difference, we can focus a little bit more on the pneumonitis. The pneumonitis could be caused by, really, anything that's not biological, like an inanimate object that causes irritation to our airway. Specifically, we're talking about our alveoli, so things that can cause inflammation. Let's think a little bit. I'm gonna draw a feather. This is gonna represent a bird's feather. Think about bird handlers. The particles in the feathers can actually cause irritation to people that are bird handlers. That's an occupation that we have to look out for. Over time, what do you think is happening? I'll just use a green color to follow that. Breathing in all those particles over time can be irritating to the alveoli, and that can cause irritation and inflammation. Another irritating agent, or irritating occupation even, are our farmers - I'm gonna draw some hay here, and I'm gonna put some leaves on top of the hay - so our farmers, especially those that deal with hay - and there's something actually called "farmer's lung." That is during harvest season, when all this hay and all this grassy material's being moved back and forth, and the person that is there has to inhale that, they can actually develop a hyper-sensitivity to it. That's gonna cause farmer's lung. In the same way the bird feather is irritating when we inhale it, so can hay. Another thing that we don't often think about - and this is gonna represent water - I want you to think about humidifiers. I'm even gonna make a little mist. Humidifiers - people that, one, use humidifiers when they're ill to help them with breathing and, two, people that work with hot tubs, and those hot tubs are constantly having that mist come off, humidifiers and hot tubs that aren't maintained properly, when you have that kind of spritz, that vaporization coming off of the water, it can actually hold mold spores. Those mold spores can be very irritating to our airways, especially our aveoli. Those are some things to think about as far as inflammation. That makes it a little bit clearer, when we're talking about pneumonia causing this inflammation and infiltration of fluid in the alveolar cavity, versus pneumonitis, which is just inflammation of the actual alveolar wall. How do we know that somebody has pneumonitis? There's a couple of things they might experience that we might be able to see. I'm just gonna scroll over here, and I'm gonna draw a face. Here is a forehead, and a nose, and lips, and a chin, so here's our face. We'll even give him an eye. The eye looks a little bit high, but I think we get the point. There's his ear and his hair. Sometimes, when you give hair, it makes it look real. This person, what do you think that they're gonna complain about with a lung like this? One of the early things is that they're gonna have a hard time breathing. They're really gonna have a hard time breathing. They might be complaining about a cough, and that cough, you can bet, is gonna be dry. It's gonna be a dry cough because remember, looking at this alveoli, and looking at the wall, we see that it's inflammation, but there's no fluid in there, so they're not gonna be coughing up anything with it. They might even experience some chest pain. These general clues are gonna lead us to believe that there's something happening at the lung level, and we need to further investigate that. Some ways that we can do that would be a chest X-ray, so we can actually visualize the lung and look for signs of inflammation. We could even do a CT scan. Possibly, if this person is really having a hard time breathing, what we might do is something called PFT. I'm gonna write that here in blue, because blue makes me think of air. I don't know why. PFT, that stands for pulmonary function test. What a PFT does is it measures how much air a person can breathe in, and how much air they can breathe out in a certain amount of time. In the presence of inflammation, you can bet that that's gonna be a decreased amount. That's how we know there's an inflammatory issue happening at the lung level. What do we do? What do we do for this patient? We know they have pneumonitis, so how do we treat it? Since we're talking about an inflammatory issue, then we have to give anti-inflammatory medications. Let's just make some tabs like this. Let's pretend these are our pills. These will be our corticosteroids We give corticosteroid medications to help decrease the inflammation. If someone is experiencing a lot of inflammation, and it's starting to [impact] the amount of oxygen that's being absorbed at the alveolar level, we want to give oxygen. We have to have intact alveoli, those ball, intact in order for us to absorb the oxygen. It's really important that we treat pneumonitis early on, because over time, this alveoli wall that we see here, it can become very fibrotic and very rigid. Think about inflammation that's left untreated for a long period of time. It's gonna become hard. It can do damage to the walls. If that happens, then we're gonna have inability to have gas exchange. That means that that could lead to decreased oxygen and a hard time breathing.