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Yes, just like, can you see it? Uh Yes, I can see it. Can someone in chat tell me if you can see it? Hopefully they can see it. Hello, everyone. I'm just waiting for someone in one of the viewers to say they can see it. Ok. Uh Anyone can, can converted you to see if you can see it. Just put like a thumbs up, just anything. Ah OK. Thank you. Ok, cool. Well, hello everyone. My name is Blue. I'm 1/4 year currently at Imperial. I'm doing medicine, of course. And today I'm gonna give your, um, med ed CSI talk about diarrhea or the case of Lucy Allen, which I think is for you. Case 15. So we may as well get started. So this is just a brief overview of what I'm gonna cover. So, a bit about defining diarrhea, acute versus chronic, the pathophysiological classifications. Um, then a bit more about, um, like IBS and IBD, um, and more specific for Crohn's Disease and then a bit more about the post reading like living with Crohn's disease. Yeah. So, um, diarrhea can be defined from a clinical perspective as having three or more liquid stools in one, like in 24 hours. And, um, stools that are more frequent than what is all stools are more frequent than what is normal for the individual lasting for less than 14 days. Um, or stool weight, more than 200 g per day. But I wouldn't get too bogged down with like the definition. Um, just they, they prob, I don't remember them asking about that, but it's three or more liquid stools in 24 hours is like the most common one. So based on duration, there are three classifications. So there's acute, which is less than 14 days, persistent, which is more than 14 days and chronic, which is more than four weeks. So this whole time like uh time scale here is quite easy to remember. So if it's under two weeks, then it's acute. If it's between two weeks to four weeks, it's persistent. And if it's more than four weeks, it's chronic. Um These questions are just more for like you to think about in your head. If you know what volume of fluid enters the gi tract every day, what percentage of these fluids are reabsorbed? And where in the gi tract is most of this fluid reabsorbed? You can just think about it. I have a lot of questions, don't worry, but these ones are more just for you to think about. So hopefully you've had a bit of time. So, um it's about 10 L of fluid enters the gi tract every day. So that's including only about like 1 to 2 to 3 L is from ingestion. So like drinking water and eating food, the the other like quite significant proportion, like 70% comes from secretions within the body. Um And then what percentage of these secretions are reabsorbed? About like nearly 99% or of the fluids that enter the body are absorbed. It's about 99%. when I say the body is sorry, I mean, the gastrointestinal tract and where in the gi tract is the most of this fluid reabsorbed. It's of course, where we have the greater surface area for absorption, which is the small intestine. Yeah. OK. So this is broadly like my little diagram for the pathophysiological classifications of diarrhea. So you have inflammatory diarrhea um which can be broken into infection IBD and other causes which we'll get into. And then in noninflammatory diarrhea, which is osmotic or secretory. And then osmotic can be either maldigestion or malabsorption and secretly can be infection or uh or yeah, will get into the other things that it can be. But yes, um we might, it, it, I know it's confusing because infection can cause both secretory and inflammatory diarrhea, but it's slightly different mechanisms. So that's what don't worry. We're gonna get into that. So first we're gonna talk about inflammatory. So I think it's helpful to understand like these things. Um this by by thinking a about how, like, how, how the, the, um, like what is the pathophysiology of it? So, for inflammatory diarrhea, it's when there's damage to the enterocytes lining the small bowel. And obviously, not only is this gonna cause things like bloody diarrhea. Um, and, you know, but also, um, it's going to cause uh reduced absorption of fluids. Um, because of there's like less surface area if you've damaged all of the, all of the, um, enterocytes. And you've like, you know, now there's loads of fibrosis and collagen. Um So yeah, that's basically how it and ii know this, this one is like a little bit blurry the green one, but there was a really good explanation of how it works. So like you have mucosal injury, which leads to an immune response which leads to like fibrosis and collagen deposition. Um and yeah, which is very accurate. Um And then, so then the causes of inflammatory diarrhea. So as I mentioned, it could be like infection, IBD or auto, so IBD inflammatory bowel disease, which is like autoimmune related, it could be due to ischemia um to like bowel ischemia, um which more commonly occurs in like elderly elderly patients and then radiation exposure. So anything like that, like physically damages the cells, like ischemia or radiation or infection of the enterocytes themselves will cause inflammatory diarrhea. And then, so the classic presentation is that it's small volume, frequent stools. Um when I say small volume, I mean, it's like less likely to cause volume, depletion and volume. I mean, like the patients are less likely to be dehydrated. They, they can definitely still be dehydrated if a patient has cholera dehydration is a very significant concern. And uh it's something that you need to treat immediately. Whereas with inflammatory diarrhea, it's, it's less severe than that. Um So then other things like tens um which is when you have the feeling that um like you have not completely like part like cleared um the the feces like in your, in your like rectal tract in your anus, then that's tenesmus blood in stool, um mucous in stool, fever, fecal leucocytes. So like white blood cells in the, in the feces and then there'll be histological signs of inflammation. So now on noninflammatory diarrhea. So, um I so non in sorry, that should say noninflammatory diarrhea at the top there here. Sorry, that's my mistake. Um enterocytes are not physically damaged, but the osmotic gradient in the bowel is out of balance. So, um so basically, um if you ha so here we have osmotic and secretory and you can see the this was um in your CSI like the little enterocytes um and the lumen and if you just wanna roughly like on a piece of paper, try and remember how they work. Um Whilst I'm actually just gonna fix this. Sorry, that's, it's irritating me. There we go. Um Yeah. Ok. Um So I'll give you a second to think about that. So, osmotic says maldigestion and malabsorption and then secretory is secretory diarrhea. Um Yeah. So hopefully you've had a minute to like think about it. I, I'm sorry, I don't have much time. So I'm gonna not like I just want you to roughly think about it. So there's my weird drawings from um second year. So in Maldigestion, um it's because there's impaired digestion. So like my little enzyme, uh there's not enough enzymes to break down the macronutrients into the or into the smaller um like, you know, monomers um that can therefore be reabsorbed. So then this leads to these larger molecules, therefore remain in the lumen um and cause um obviously pool water via osmosis.