What is cyclic vomiting syndrome and how is it diagnosed?

Steve Wartenberg: Welcome back to our ongoing series on cyclic vomiting syndrome with Dr. V. I'm Steve Wartenberg, your moderator, and this is Dr. Thangam Venkatesan. Let's tackle the big picture question. What is CVS and then we'll get to how is it diagnosed?

Thangam Venkatesan, MD: Cyclic vomiting syndrome, as the name implies, is a disorder of vomiting. It's also called a DGBI, which is a disorder of gut-brain interaction, and essentially there's a connection between the brain and the gut. And so, the brain is like a supercomputer that actually controls all our sensations and motility and so on in the gut. Just like you have a stress or a tension headache, there are various things that can happen and many people think, "Oh, it's a stomach disorder." But just for your knowledge, the center for vomiting is actually in your brain.

The way it's really characterized is its stereotypic episodes of nausea and vomiting and many other symptoms that usually will occur just out of the blue, and they can occur at varying frequencies. Some people might have it once a month, but some people might have it more frequently. The interesting thing is people actually go back to normal in between episodes, or near normal.

Steve Wartenberg: But how about the stress on the person in between because it's going to happen again? It could happen at work. It could happen at school. I guess there must be some psychological stress, even PTSD, associated with it.

Thangam Venkatesan, MD: Well, I will say that as far as stress is concerned, stress can be a trigger, both positive and negative stress. I have several patients, for instance, sometimes in children stress is triggered by, say, vacations. But I think the most important thing is really first diagnosing it.

Steve Wartenberg: Yes, that's what I was going to ask you. How do you diagnose this? And I'm getting the impression that over the decades, the past several decades, it was probably misunderstood and misdiagnosed.

Thangam Venkatesan, MD: CVS is really diagnosed by what we call the Rome criteria. We now have what is the Rome-IV iteration for cyclic vomiting syndrome, and essentially it means that you have to have at least three of these episodes. Three-

Steve Wartenberg: Three of the four.

Thangam Venkatesan, MD: No, you have to have at least three episodes of vomiting in a year.

Steve Wartenberg: In a year, okay.

Thangam Venkatesan, MD: Two in the previous year. Typically, they can last from few hours to up to a week, and in general, you have to have periods of normalcy. If you're vomiting every single day, you probably don't have CVS. CVS episodes are really abrupt in onset, and then they start suddenly, like I said, lasting for hours or maybe a week, and then you go back to normal in between episodes.

The periods of normalcy usually last for at least a week or more, and you need all of these to make a diagnosis. Of course, there are some things that can mimic CVS or look like CVS, so you want to make sure that people don't have intestinal obstruction and so on. And so, you rule out other disorders that might mimic CVS. If you meet all of those criteria, then we make a diagnosis of cyclic vomiting syndrome.

Steve Wartenberg: You've talked about something before, the phases of CVS, so let's go into a little more detail on that. What are they in each phase?

Thangam Venkatesan, MD: The cyclic vomiting syndrome episode itself has multiple phases. Initially, you have a prodromal phase, something like a migraine headache, and in this phase, patients can experience multiple symptoms. They can have nausea, they can have belly pain, or they just know that they're going to have a CVS episode. Typically, what happens in the prodromal phase is that I might prescribe them medications to try and control these episodes. However, unfortunately, many of these patients either have not been diagnosed and they can progress to what is called the emetic phase. They have violent nausea, vomiting, retching. They have multiple symptoms, even if though we call it a vomiting syndrome, they can have abdominal pain, they have pallor and they have so many other symptoms going on and it's very severe, and then they actually recover.

Now, sometimes they recover very fast, and you might even see children running around and having a hamburger three hours after the episode. It's very important to make sure that you don't tell them or you don't think they're faking it because this is real. This is how an episode occurs. It's like an on-off switch.
 
Steve Wartenberg: The prodrome phase, is that in a sense an early warning system, and if someone is at work or school, would they have time to go somewhere where they could be home or safe or at least isolated?

Thangam Venkatesan, MD: Exactly. That's a great question and that's why I say it's very important to recognize the prodromal phase. And so, during that period, I always tell my patients to take all their rescue medications and use it so that they can prevent this progression to an emetic phase.

Aside from vomiting and severe nausea, you can actually have belly pain or abdominal pain, which is seen in at least 80% of patients with cyclic vomiting syndrome. They can look, like I said, they can look very pale, they can have chills, and they can feel hot and cold at the same time. Some people actually describe being in a conscious coma, they cannot even talk during an episode.

Steve Wartenberg: Wow. If someone would go to the hospital with these symptoms and is undiagnosed, that kind of doubles the problem, whereas someone who is diagnosed can somehow indicate to the person in the ER.

Thangam Venkatesan, MD: Absolutely. Absolutely. Typically, in my CVS clinic, all of my patients will have an ED protocol and they really have it as part of their after-visit summary. And so, that is something that I ask them to share with ED physicians, other local providers and so on, so that they know what has to be done during a CVS episode.

Steve Wartenberg: That just reinforces the importance of being diagnosed. Is there any way you investigate or look at the person through, I don't know, scopes or anything to determine what's going on?

Thangam Venkatesan, MD: I do think that people need to have an upper endoscopy. You need to make sure they're not having sort of a gastric volvulus or intestinal obstruction and things like that. I would also recommend a CT scan or some sort of imaging study of the abdomen. What we don't, however, recommend is repeated unnecessary tests.

Steve Wartenberg: These investigations are ruling out other things-

Thangam Venkatesan, MD: Few other things

Steve Wartenberg: ... Which could lead you to reinforce your diagnosis of CVS.

Thangam Venkatesan, MD: Exactly. And so, I would history, history, history.

Steve Wartenberg: Okay. Now, what about something, I've heard of a gastric emptying test. What is that?

Thangam Venkatesan, MD: Unfortunately, there's not a great correlation or it is not really very helpful at all in cyclic vomiting syndrome. The test can actually be normal, it can be rapid or it can even be delayed, and it really doesn't help in the diagnosis at all. This again, like I said, is an episodic disorder. There are chronic conditions of nausea and vomiting, and this is what we call an episodic disorder. The patient, like I said, will be very sick and then they're okay, or they go back to baseline. They can have some baseline symptoms and then they're sick again.

Steve Wartenberg: Wow. Okay, so that's great. That's a lot of information. I'm going to put you on the spot. Can you summarize what we just learned about CVS in terms of diagnosis and treatment?

Thangam Venkatesan, MD: Absolutely. I think for both patients and the medical community, what you really need to remember today is that, A, cyclic vomiting syndrome is a disorder of gut-brain interaction. It is diagnosed by something called Rome criteria, and these are published and well-established criteria. The diagnosis is really based on a clinical history. We recommend minimal testing, including an upper endoscopy and maybe an imaging study. It's very important to avoid unnecessary and repeated testing for these patients. I think prompt diagnosis and treatment can really improve patient outcomes.

Steve Wartenberg: Thanks for watching, and stay tuned for more episodes on what you need to know about CVS with Dr. V.

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