What is gastroenteritis?

- [Voiceover] So, gastroenteritis is kind of a big word, but I think like all big words, the best way to really understand it is by breaking it down. So, "gastro" refers to stomach. "Enter" refers to small intestine. And "itis" refers to inflammation. So, there are really two different types of gastroenteritis. There's acute gastroenteritis, and there's chronic gastroenteritis. Acute gastroenteritis doesn't last very long. It's usually about a few days to a week. Chronic gastroenteritis, on the other hand, is persistent. It lasts for a pretty long period of time. We're going to mostly be talking about acute gastroenteritis. So, if people have acute gastroenteritis, they don't usually say, you know, like, "I have acute gastroenteritis." They usually say something like, you know, "I have the stomach flu," or "the stomach bug," or "a stomach virus." So, anyone who said they've had this is kind of familiar with some of the symptoms associated with it. So, to look at those symptoms, why don't we actually look at the gastrointestinal tract over here? So, here is the stomach, and here is the small intestine in green. So, after you consume a meal, you know, you'll have some stuff in your stomach that your digestive system is really trying to digest and then absorb. But when you have gastroenteritis, your digestive tract can't do that, so now you have all this stuff that your body is going to want to expel. So, how is it going to do that? Well, it can either come out this way, right, through your esophagus, and that's really why, you know, you experience some vomiting and nausea. It can also come out from the other end as well, right, and that's why a lot of people may experience some diarrhea. So, there's a lot of nutrients and a lot of water that you've consumed but your body isn't taking it. And because you're vomiting and excreting a lot of water out, you're not getting that water into your system. So, you'll be pretty badly dehydrated as well. Some other symptoms can include things like abdominal pain and a fever. And usually in acute gastroenteritis, these symptoms last for about a few days to at most a week. So, what's causing all these symptoms to occur? What causes gastroenteritis? We know sometimes people call it the stomach flu, and I think that can be a bit misleading. The ordinary flu is caused by the influenza virus, but this virus has absolutely nothing to do with gastroenteritis. There are a number of different infectious pathogens that can cause this instead, so you may have some different viruses or some different bacteria. So, a few examples, right, some really common examples of the many different pathogens would be, you know, like the, the rotavirus, the norovirus. So, these are examples of viruses that could cause the disease. An example of the bacteria would be something called enterotoxigenic E. coli. So, this is just a really fancy name for some bacteria that could cause the disease. But, all in all, there are a lot of other types of pathogens that could cause it as well. So, how do these pathogens get into your system to begin with? It's usually through fecal to oral transmission. So your feces is the stuff that gets undigested and doesn't get absorbed into your system, and it gets excreted as waste. That feces can contain the pathogen, so it's contaminated. And "oral" just refers to someone's mouth. So, maybe someone with gastroenteritis uses the bathroom, and they wash their hands but not well enough. So their hands might actually be contaminated with some of the pathogen. And then, they may go on to touch other objects, right, surfaces and food and water, that you may touch. And then, if you touch those with your hands or if you eat the contaminated food or water, then you can give the pathogen very easy access to your own gastrointestinal system. So, once it's in your system, what is it going to do? So, going back to our diagram over here, you have this, this wall that really kind of extends over the entire gastrointestinal tract, you know, your stomach and your small intestine, and so on and so forth. So, we call this, this wall or this lining the gastrointestinal wall. And this is what we're going to be focusing on. So, let's actually zoom in on that a bit. So, here, I kind of have a zoomed in picture of that. And I want to mostly focus on this green structure over here. This green structure is just the epithelium. It contains all of the cells that will be specialized for digestion and absorption. So, maybe you eat some food over here, right, that's being partially digested. But in the food that you ate, maybe there were some of the pathogen. The pathogen is then going to invade the epithelium, so it's going to invade those cells, and those cells are going to die off. These epithelial cells are going to kind of slough off of the lining over here. So, maybe you'll have some dead epithelial cells in the partially digested food that you're trying to eat. So, now, you don't have those epithelial cells to digest and absorb food and water. So, you're going to actually have a lot of water here. And instead of going into your system, it's just going to stay here. So, now, you can't digest some of the foods and that may lead to some vomiting. And because this has so much water in it, it's going to come out as diarrhea. So, the water is really staying here. It's not getting into your system, and therefore, you also have dehydration. And there's actually some more stuff in here as well. Remember that the "itis" in gastroenteritis refers to inflammation. That basically just means that the immune system is here, so the immune system may be around this gastrointestinal wall, so you have a whole bunch of white blood cells over here as well. And then, maybe they'll find their way into this, this little mixture over here as well. So, you have a lot of stuff in here that you really don't want to be in here, and you're not getting that stuff into your system. You're just expelling it out, because the pathogen has destroyed the epithelium. So, maybe you're displaying all of these symptoms and you think you may have gastroenteritis. So you go to the doctor. You really want to confirm this. So the doctor may conclude that you have gastroenteritis, right, based off of the symptoms alone. But they may actually do a few more tests, right, just to verify a few things. So, maybe you want to find out what pathogen exactly is in your system. That way, you can know what treatment options you can take. So, what the doctor can do is they can order a stool sample. They can then send this sample off to a lab to evaluate what exactly is in there, because remember, your feces is going to be contaminated with the pathogen. For example, it could be the norovirus. It could be that enterotoxigenic E. coli. Maybe it's that rotavirus that I talked about earlier, or maybe it's something else. But this is really just to verify what's in there. They can also have a blood test done. So, they may actually send this off to a lab, right, to evaluate the blood. When you look at the blood, you're not actually looking for the virus. You're looking for signs that the person may have some dehydration. That would include high levels of sodium and creatinine. If these exist in high levels, then there's a pretty good chance that the person is dehydrated. So, you've confirmed that the person has gastroenteritis. So, how can we treat that? We can put the person on oral rehydration therapy. This is really just a fancy way of getting the person to drink a lot of fluids. So, drinking a lot of water, drinking fluids that contain a lot of sugars and salts and all that stuff, because the person is pretty badly dehydrated. They really need to get some water. If it's getting pretty severe, you can actually have the person be put on an IV fluid. So, sometimes, people are given antibiotics. This can be helpful if it's being caused by a bacteria because antibiotics target bacteria. But if it's targeting a virus, then these won't really be helpful, because antibiotics do not target viruses. It's also important to be aware of the fact that you have a lot of good bacteria in your gastrointestinal system that help digest and absorb food. So, these antibiotics could potentially damage those bacteria as well. So, whether or not you give someone antibiotics really depends on the nature of the pathogen and the individual. So, there isn't really a medicine to kind of treat gastroenteritis or cure gastroenteritis. It kind of goes away on its own after about a week or so. But how can we prevent it so that we don't have to treat it to begin with? The absolute best thing to do is to just practice good hygiene. So, whether or not you have gastroenteritis, it's always a good idea to really thoroughly wash your hands after using the bathroom. You should also take care to drink water that's definitely decontaminated and clean. And you should also make sure to cook your food really well, just to be sure that it isn't contaminated with the pathogen so that anyone who eats it could get gastroenteritis.