Melanie Cole, MS (Host): Welcome to Better Edge, a Northwestern Medicine podcast for physicians. I'm Melanie Cole. And joining me today is Dr. Joy Liu. She's a gastroenterologist and instructor of Gastroenterology and Hepatology at Northwestern Medicine, and she's here to highlight gastroparesis today.

Melanie Cole, MS: Dr. Liu, it's a pleasure to have you join us. I'd like you to start by telling us a little bit about your areas of clinical and research focus.

Joy Liu, MD: Yeah, of course. And thank you for having me on, Melanie. So, I joined the faculty in September of 2022. And my areas of clinical interest include disorders of gut-brain interaction, conditions such as irritable bowel syndrome, chronic constipation, pelvic floor disorders. But in particular, I am focusing on helping to build and strengthen a comprehensive gastroparesis and chronic nausea and vomiting program at Northwestern. And because of this, my areas of research focus on this as well.

Melanie Cole, MS: That's so interesting. So, why don't you tell us about gastroparesis? How prevalent is this condition?

Joy Liu, MD: Sure. So, gastroparesis, as we define it with typical symptoms of nausea, vomiting, bloating and satiety, pain that have been going on for a chronic period of time, along with a gastric emptying scan that shows delay, is not very common. It's probably got a prevalence of maybe 50 to 200 cases per every 100,000 individuals in the United States. But there are a larger number of individuals who have gastroparesis-like symptoms. And telling the difference between gastroparesis and these other kinds of symptoms, you know, whether that represents functional dyspepsia or chronic nausea, vomiting of another origin, can be pretty tricky, and it can be confusing for patients. So, I think it's important to educate our patients about the differences between these, and to ensure that they, you know, truly meet criteria for gastroparesis when we see them.

Melanie Cole, MS: So, what do we know about the causes, Dr. Liu? And how does knowing what the underlying cause affect your management decisions?

Joy Liu, MD: So, gastroparesis can be caused by a variety of things. Some of the most common causes of gastroparesis include diabetes, whether that's type 1 or type 2 diabetes, complications after foregut surgery in particular, postviral gastroparesis and a category of gastroparesis that we call idiopathic, meaning that we have not identified one specific cause.

In terms of how common each of these causes are, diabetes probably accounts for at least a quarter, some studies estimate up to 50% of gastroparesis. Whereas post-surgical and idiopathic gastroparesis may comprise about 25% of the population each.

In terms of how the underlying cause affects management, we do think that patients who have gastroparesis and also have diabetes may respond better to prokinetics such as Reglan or, in certain cases, domperidone, which is actually rarely prescribed in the United States. In addition, patients who have diabetes or potentially idiopathic gastroparesis may be candidates for other forms of non-pharmacologic treatment, such as G-POEM or the gastric neurostimulator, which is also called Enterra.

Melanie Cole, MS: Dr. Liu, you spoke briefly about symptoms. I'd like you to speak about what patients tell you a flareup feels like, how you diagnose this. And when you're diagnosing this, how do you differentiate it from functional dyspepsia in management, in diagnoses? Speak about that a little bit.

Joy Liu, MD: So, many of our patients will experience chronic symptoms, you know, having almost daily symptoms of nausea, vomiting or the other symptoms that I mentioned. A flare is really characterized by an exacerbation of those symptoms where the patient may be experiencing more episodes of vomiting than usual. They may be nauseous every day of the week instead of just several days or they may be experiencing such profound satiety that they start to lose weight. Those are some of the signs that are concerning to us that indicate that they may need to be evaluated more urgently or may even require hospitalization for IV fluids, IV medications, and potentially even nutrition interventions.

So in terms of managing these flares, it can be tricky. Gastroparesis, we think exists along a spectrum with other conditions of chronic nausea and vomiting, and functional GI symptoms such as functional dyspepsia. Functional dyspepsia is characterized usually by postprandial satiety. There may be bloating, abdominal pain, and oftentimes nausea is a significant feature of functional dyspepsia. So, the reason that it's important to differentiate between these two is really because of the importance that our patients attach to the diagnosis in question. There is some stigma with any functional GI disorder and many patients feel as though they are not going to be taken seriously or they're going to be invalidated if they have a diagnosis of functional dyspepsia as opposed to gastroparesis. And we always want to reassure them that that is not true and we will try to treat them as best they can regardless of what their diagnosis is.

In terms of how the management of these conditions may differ, we actually use many of the same medications to treat the symptoms that people describe to us. And when I treat these individuals, I like to ask them, "What is the most important symptom for us to address? Is it the lack of appetite, and wanting to eat more? Is it the having multiple episodes of vomiting a week? Is it abdominal pain?" And we really try to target medications to their individual symptoms. At the same time, we know that, from studies from the National Gastroparesis Consortium, that about 40% of patients will change their diagnosis over the course of the year. That means that 40% of individuals who start out with a diagnosis of gastroparesis, if you retested them with a gastric emptying scan later that year, they might not have an abnormal gastric emptying scan anymore and therefore, be classified as functional dyspepsia, and the reverse is true as well. That's why even though we try to make a distinction between the diagnoses, it doesn't truly affect our management in terms of how much we try to help these patients.

Melanie Cole, MS: Thank you for that. So, I'd like you to expand a little bit on management. What are some best practices for managing gastroparesis?

Joy Liu, MD: The best practices for managing gastroparesis start with making the correct diagnosis. There was a study that came out of ACG last year that showed that about two-thirds of individuals who were referred to a tertiary academic center for gastroparesis actually did not meet criteria for gastroparesis. And other studies have shown that, you know, in some cases, only about 15% of patients who were coded as having gastroparesis had the confirmatory testing that would have supported that.

So, it's very important to get an accurate and thorough history when making a diagnosis of gastroparesis and, in addition, to make sure that we have a really good quality gastric emptying scan. Our society recommends having a four-hour exam with a standard Egg Beaters meal. So, that is step number one.

In terms of treatment for gastroparesis, we, you know, have very limited options that are FDA approved with a high level of evidence. And this is an area that is important for all of us to keep working on. There's only one medication that is FDA approved to treat gastroparesis, and that is Reglan. We know that Reglan can be associated with some rare but potentially serious adverse effects such as tardive dyskinesia and QTc prolongation. And because of that, we recommend using a drug holiday when patients are going to be taking Reglan chronically. In addition, it's important to monitor these patients with regular EKGs and electrolyte panels to make sure that they're not going to be at an increased risk of arrhythmia.

In addition, an appropriate diet for gastroparesis is actually considered first line management. And in my practice, I think that this is something that is not implemented as well as it should be, you know, in terms of promoting more of a pureed or a liquid diet, a diet that still has some fiber component and is healthful and nutritious. We see far too many patients who are eating only canned fruits and vegetables or avoiding any kind of fiber at all because of fears of developing a bezoar or because they were told that they should not eat fresh fruits and vegetables ever and, you know, we want to make sure that they are still getting all the nutrients they need.

In addition, we know that abdominal pain, which can be a very significant part of the presentation of gastroparesis, is difficult to treat because we don't have good trials for therapeutics that treat abdominal pain. The best thing that we have currently is the use of tricyclic antidepressants, in particular, amitriptyline. Nortriptyline had been considered an option perhaps for patients who were having side effects from amitriptyline. But studies have not shown it to be more effective than placebo. And so, that is still an area where more work is needed, and we really have to work with patients on an individual level to figure out what is going to help them the most.

Melanie Cole, MS: Dr. Liu, I'm so glad that you brought up diet. And as we get ready to wrap up, I'd love for you to speak about the multidisciplinary approach needed for these patients. When you bring up such a strict diet like that, how do you see patients able to live a good quality of life with it? And who helps you work with these patients? Tell us a little bit about what makes Northwestern Medicines approach to gastroparesis so unique.

Joy Liu, MD: Certainly. This is one of the things that I'm most enthusiastic about, because I think that our resources at Northwestern and the people who are in our system here give our patients a real edge in terms of managing this condition.

So in terms of dietary therapy, first of all, we always stress that patients should be getting good nutrition, they should not have any nutritional deficiencies and, in particular for people who have lost a lot of weight, how do we make sure that we achieve weight stabilization and start to gain back weight in a healthy way? How do we evaluate patients who may have developed disordered eating because of their GI symptoms and the fear of triggering those symptoms? Obesity is actually pretty prevalent in gastroparesis as well. And so, co-managing these individuals with bariatric dieticians or endocrinologists becomes important.

Now in terms of our specific resources for gastroparesis at Northwestern, we have whole range of people who I, you know, work with and really appreciate having on my team. So, our motility and neurogastroenterology team, you know, which comprises myself, Dr. Darren Brenner, Amy Kassebaum, and others; our GI dieticians, Beth Doerfler and Kristen Kimble, who see not only our patients with gastroparesis, but other GI disorders as well; our behavioral medicine and, and GI psychology experts who help these patients with the coping mechanisms and can really help improve quality of life from the suffering that these GI symptoms bring on, these are really, I think, the core of our medical management for gastroparesis.

For individuals who are refractory to medical management, we do have interventionalists who are able to perform procedures such as G-POEM. Dr. Aziz Aadam performs G-POEM here. One of our surgeons, Dr. Jeff Fronza, recently started to offer placement of the gastric neurostimulator or the Enterra. In addition, we have providers across the system who are able to help us manage comorbidities associated with gastroparesis, such as pain specialists and endocrinologists.

I also think that one of the benefits of being at Northwestern is that we have the resources to engage in clinical trials for novel therapeutics and for diagnostics that may change the way we diagnose and manage gastroparesis in the future. We are just starting to engage with some of these research opportunities, and I look forward to telling you about results in the future.

Melanie Cole, MS: We look forward to that too. So, please let us know when you have some updates for us and come join us again. You are an excellent guest. This was so informative. Thank you so much, Dr. Liu, for joining us. And to refer your patient or for more information, please visit our website at breakthroughsforphysicians.nm.org/gastroenterology to get connected with one of our providers. That concludes this episode of Better Edge, a Northwestern Medicine Podcast for physicians. I'm your host, Melanie Cole. Thanks so much for joining us today.