Who doesn't want to talk about IBS before lunch? But I'll, you know, my goal is to really give you an overview, help you understand these conditions and then get you to lunch. So if it's okay, I'm just going to go through these questions. So let's talk about inflammatory bowel disease. So inflammatory bowel disease is IBD. We'll talk about IBS later, which is irritable bowel syndrome, but IBD includes two conditions, so Crohn's disease and ulcerative colitis. Oh, let me actually go back. So Crohn's, so these are just chronic inflammatory conditions of the gut. And Crohn's disease is one of those that can affect anywhere from the mouth all the way down to the anus, but most commonly the colon and the small intestine, whereas ulcerative colitis is limited just to the colon. In terms of the distribution, Crohn's is typically patchy, typically doesn't involve the rectum, although sometimes it can. And we'll get into sort of the way the inflammation goes, but essentially you can find inflammation in the small intestine, large intestine, one or the other, whereas ulcerative colitis typically begins in the rectum and then works its way up. So some people, when they come in, will just have inflammation in the rectum, some just on the left side, but some will also have involvement of their entire colon. So in terms of the layers of involvement, so on the far left, you can see what a normal colon looks like with sort of just that nice, healthy pink mucosal layer. Crohn's disease causes inflammation in a transmural manner, meaning it affects all layers of the GI tract, so like the mucosa, submucosa, and so on. And so as a result, it causes changes that we see during colonoscopy to be a little unique. It can cause deeper or fissuring ulcers, sometimes cobblestone-ing or sort of this nodularity of the mucosa. And then when our patients get surgery, surgeons can actually see this sort of fat wrapping or fat creeping in the areas of inflammation. In ulcerative colitis, we think about it really being limited to the mucosa. Now there are some nuances to that, but typically what we'll see on the inside, rather than the deep ulcers and Crohn's, we'll see more of the superficial ulcers. So some of the symptoms of Crohn's include abdominal pain, diarrhea. Those are probably the two most common, but patients can also present with nausea and vomiting, perianal disease, which refers to fistulas and abscesses, or they can have more systemic symptoms like fever and weight loss. So let's talk about why. So inflammation in the GI tract can cause a lot of these symptoms, like abdominal pain and diarrhea. However, with Crohn's, because it affects all layers of the tract, it can cause narrowing due to chronic inflammation, and that results in scarring. So you can imagine it's a tube, and if that tube becomes more narrow, that becomes a point of obstruction. And so that's why some patients might actually have nausea and vomiting and bowel obstruction. Because Crohn's, again, goes through all layers of the GI tract, it can track from one part of the bowel to another. And so patients can have fistulas, so one connection of the bowel, usually the inflamed bowel, to another part of the body. And in the setting of perianal disease, that can result in fistulas to the skin, just right outside the anal canal, or abscesses. So how do you diagnose Crohn's? It's really a combination of things. Typically it's symptoms, it's labs, it's looking at imaging. Colonoscopy is truly the gold standard for diagnosing Crohn's and ulcerative colitis. But as we've heard from some of our other speakers, sometimes people have inflammation out of reach of a colonoscope, so we rely on things like imaging and capsule endoscopy. And then on pathology, we see chronic inflammation. So that's really distinct from some of the other forms of inflammation we see. And in probably less than 30% of patients, we might see what's called a granuloma, so this sort of loose collection of inflammatory cells. When I'm talking to patients, there's two basic treatment goals. One is clinical remission, and the other is endoscopic remission. So clinical remission is just that you feel well, you don't have pain or diarrhea or bleeding, and that you have a good quality of life. You can go to meetings, and you can travel. The other is endoscopic remission. That really refers to the absence of ulcers during a colonoscopy. Now ideally, we want them to achieve these things without having to stay on steroids. And then once we get them there, we want to keep them well. There is some question about whether we should start targeting microscopic forms of inflammation called on histology, but that remains to be determined. So in terms of treatments, sorry, did I skip the ulcerative colitis slide? I might have. No, I think I might have. Anyways. We'll just go through this, but treatment. So essentially, the best way to think about therapies for inflammatory bowel disease are really that we're trying to control the chronic inflammation. And like Bill was talking about with hepatitis B, we can't cure it, but we can control it. And it's the same thing for inflammatory bowel disease. We use antibiotics mainly when people have things like abscesses or fistulas. Amino cell acylates, I describe these to my patients as sort of topical anti-inflammatories for the gut. They do not cause immunosuppression, and they're typically more helpful in the milder forms of ulcerative colitis, sometimes even Crohn's. Now steroids work really well when they work. Essentially, they just totally dampen inflammation, but they carry a lot of side effects. And so usually I use these as a bridge to something else. Immunomodulators, biologics, and small molecules, all of these are agents that act on the immune system in different ways, whether just to globally dampen inflammation, decrease inflammation at the tissue level, decrease our inflammatory cells from getting to the gut. They all have different ways of working, but the newer ones, the biologics and small molecules, those are targeted at the mechanisms that really drive Crohn's and ulcerative colitis. Now for Crohn's, some of the other therapies that we might need are surgical. So patients might need a disease segment removed. They might need a fistula, like if they have a really superficial fistula, a little fistulactomy. Some of the fistulas or the tracking of the inflammation from one part of the bowel to the perianal area can go through the sphincters. And so you don't want to put a knife through that to get rid of the fistula, because you can imagine it'll damage sphincter function. And so for those patients, we will typically drain the fistula and abscess and then put in acetone. And acetone is like kind of a little soft zip tie to keep it open. It seems really counterintuitive to put a little tie in to keep a fistula tract open. But the reason we do that is to really avoid more complications, like worsening fistulizing disease or new abscesses. And then the goal is really to treat them with medical therapy, so hopefully those fistulas will close. Oh, here's the ulcerative colitis slide. So ulcerative colitis, so we kind of talked about this already. But essentially, just remember that it's a mucosal process, typically more superficial, starts in the rectum, and then moves its way up the left side. So for ulcerative colitis, it's a lot easier in some ways to diagnose, because you can do a sigmoidoscopy or a colonoscopy. Sometimes Crohn's involves more testing. The symptoms are similar to Crohn's disease, but I'll just highlight that patients more often present with bleeding, pus, or mucus in their bowel movements, and a lot of urgency. But a lot of the other symptoms are similar. So tenesmus is the sensation that you have to go, even though there might not be anything in the rectum, and that's usually due to chronic inflammation in that area. So diagnosis is, again, by colonoscopy. On the right, you can see this red, inflamed, friable mucosa. You can't see those nice sort of light pink lining with the vessels anymore. And then you may see superficial ulcers as well. Over time, though, well, so sometimes you can see really deep ulcers, and you see that on the left. That's a more poor prognostic sign, and typically those patients often need our biologic therapies or are at high risk for needing surgery. But they can develop pseudopolyps. So for those of you I was talking to during the break who work on SNARs, you can imagine that these pseudopolyps are really difficult to distinguish from standard polyps that might be at an increased risk for colon cancer. So in my world, it's incredibly hard to survey these patients, and we do a lot of polyp sampling. The only difference with these is that they bleed a lot easier. So this is sort of the way to think about treatment, but what I'll just say is that in practice you're going to classify your patient into sort of that mild to moderate or low-risk category or a moderate to severe or high-risk category, and then that's how you think about treatment. And I think the way you do that is you really think about sort of their past, what you see now, and their risk for complications. But essentially most of our therapies are therapies that target the immune system or involve surgery. So microscopic colitis, and now we're going to switch gears, is totally different. So microscopic colitis actually looks normal on a colonoscopy, but at the microscopic level you see chronic inflammation. However, these patients, even with a normal appearing colon, can have chronic watery diarrhea. There are two types of microscopic colitis. So there's collagenous colitis, which is characterized by a small thickened collagen band in the lamina propria, or you can have lymphocytic colitis, which is just an increase in the lymphocytes in the epithelial layers. What's a little bit different from microscopic colitis at the microscopic level is just that you have relative preservation of the crypts, whereas in conditions like Crohn's and ulcerative colitis you see a lot more crypt inflammation and crypt destruction. Again, diagnosis of microscopic colitis is via colonoscopy with biopsy. So treatment is a little bit different. So treatment really focuses more on symptoms, but also trying to control the inflammation. So some patients with milder forms can get away with antidiarrheals or maybe even 5-amino salicylates, so things that we might use in ulcerative colitis. Typically if they are symptomatic, the most effective treatment is budesonide. It's a very mild, weak steroid. Almost completely gets metabolized by the liver, so your body doesn't get as much steroid-related side effects. However, patients often can relapse after stopping treatment or just over time. So some end up on therapies that we might use for IBD. And then this is the last topic, irritable bowel syndrome. So this is considered a functional GI disorder, also a chronic condition affecting the lower GI tract. And it's characterized by abdominal pain or discomfort and a change in bowel habits. So IBS is really common. It affects one in seven Americans, so about 15% of the US population. In contrast, conditions like inflammatory bowel disease, so Crohn's or UC, affects maybe 2 million Americans, so less than 1%. And women are twice as likely to have IBS compared with men. There's three different types of IBS. IBS-D, which is diarrhea predominant, IBS-C, which is constipation predominant, and then IBS-M, which is sort of mixed diarrhea and constipation. So unlike inflammatory bowel disease, where we really rely not just on symptoms but more objective markers like colonoscopy, imaging, labs, IBS is a diagnosis purely based on symptoms. So it's characterized by abdominal pain or discomfort with at least two out of three of the following features. As it's relieved with defecation, the onset is associated with a change in the frequency of the stool or a change in the form of the stool. So what causes IBS? There's a lot of factors. It's thought to be a condition where even with normal distention or normal bowel movements, there's just sort of a heightened sensitivity to what's going on inside the gut. But there are a lot of things that can trigger that. So there can be psychosocial factors like the loss of a loved one or a move or an incredibly stressful situation. Infections can trigger inflammation in the gut resolve but then still result in some residual hypersensitivity. And then these can also result in altered bowel motility. It is also associated with an imbalance of gut neurotransmitters, especially things like serotonin. So again, the diagnosis is clinical. But of course, in any patient presenting with pain, diarrhea, and so forth, you want to make sure that you check for alarm symptoms. So if they're over 50, if they're losing weight, if they have anemia or GI bleeding, they need to have more evaluation before they can be labeled as having IBS. And then as far as treatment goes, so we start with lifestyle modifications. Fiber can be really helpful, whether patients have diarrhea or constipation or both. There's a lot of diets out there for IBS. You may have heard of the low FODMAP diet. There's also other diets. Some patients go gluten-free, dairy-free. And those can actually help a lot. And then psychological evaluation, we have a lot of patients where stress can make a huge impact, depression, anxiety. And so actually having therapy can have a positive impact on their gut. In terms of symptoms, you can use antidiarrheals or laxatives, depending on the issue. Antispasmodics will help relax the gut so people don't get as much cramping. And then you can use things like anxiolytics and antidepressants. And not just so much for anxiety or depression, but actually because they also work on the neurotransmitters in the gut. There's also specific receptor drugs that have been approved for IBS. Now these will typically either work on the serotonin receptors, the opioid receptors, or the ion channels that are involved in secretion of various substances, whether bicarbonate or chloride. And essentially they work to either help with constipation or diarrhea. And then of course there are alternative modes of therapy as well that can make a big difference too. So that's it. Hopefully that was helpful. Thank you.

inflammatory bowel disease

Crohn's disease

ulcerative colitis

irritable bowel syndrome

gastrointestinal tract