Cyclic Vomiting Syndrome: Are We Overlooking Cases?

Cyclic vomiting syndrome (CVS) is often underdiagnosed, according to a recent study published in Neurogastroenterology & Motility. Researchers from the United States have highlighted limited awareness of this condition as a significant contributing factor to underdiagnosis.

In the study, approximately 90 adult patients with CVS maintained a daily diary for 6 months, recording their symptoms, frequency, and duration of episodes. Researchers found that CVS manifests in diverse ways, revealing a gap between the current diagnostic criteria, based on expert consensus rather than evidence, and actual patient experiences.

“Study results highlight that the episode number depends on definitions used,” the authors wrote. They criticized the requirement for a minimum 7-day interval between episodes, noting that it does not match clinical reality and could lead to underdiagnosis.

Expert Insight

Claudio Romano, MD, PhD, heads the Pediatric Gastroenterology and Cystic Fibrosis Unit at the University of Messina, Messina, Italy, and is the current vice president of the Italian Society of Pediatric Gastroenterology. Speaking with Univadis Italy, a Medscape Network platform, he acknowledged that CVS can be difficult to diagnose when symptoms are not accurately classified. However, he expressed partial disagreement with the conclusions of the study.

Cyclic Vomiting in Children

“Cyclic vomiting syndrome is now classified as a migraine variant,” Romano explained.

The primary symptom may suggest a gastroenterological condition, but it is actually a migraine equivalent that presents with vomiting episodes.

Romano described two forms of CVS: Pediatric onset, which can begin as early as age 1, and adult-onset, which typically occurs later in life. In children, the primary symptom is severe uncontrolled vomiting, which occurs in episodes lasting hours or days. These episodes typically begin early in the morning, with vomiting occurring three to four times per hour, accompanied by symptoms such as photophobia, headaches, abdominal pain, and epigastralgia. Once an episode ends, the patient becomes entirely symptom-free until the next episode.

Delayed diagnosis is common because vomiting episodes are often misattributed to viral infections, food allergies, or intolerance.

“If this clinical condition is not suspected, it is often because there are no precise diagnostic criteria beyond the cyclical nature of vomiting. The episodes appear at defined intervals, with the patient remaining completely well between episodes. Patients with a brain tumor rather than a metabolic disease have chronic vomiting, without the asymptomatic interval lasting 2-3 months,” Romano noted. The differential diagnosis of CVS includes brain tumors and disorders affecting the central nervous system, gastrointestinal tract, and eyes.

Adult Presentation

In adults, CVS often has a later onset and is more common in women than in men. Neurologic symptoms such as headaches and migraines are more prevalent and are accompanied by gastrointestinal symptoms.

“Referring the patient to a gastroenterologist means entrusting the case to a specialist who may not be the most appropriate provider. The ideal case manager should be a neurologist or neuropsychiatrist,” Romano said. He also pointed out that his center treats adult patients because of the lack of dedicated CVS centers for adults.

Once diagnosed, CVS can be managed with preventive treatments, including antiserotonergic medications, newer migraine drugs, and antiepileptics, to reduce the frequency of episodes. Antiemetics, such as ondansetron, are used for acute episodes, although they are effective in less than 50% of patients. “In patients who respond, taking the antiemetic early in the episode can shorten its duration from 6-8 hours to just 1-2 hours, which is a significant improvement,” Romano explained.

Romano also stressed the importance of considering cannabinoid hyperemesis syndrome in adults presenting with recurrent vomiting in adults. Cannabis use can trigger vomiting episodes rather than alleviate them, and cannabinoid hyperemesis syndrome should be ruled out in adults with frequent, unexplained vomiting.

Key Clue

How common is CVS? “There are no epidemiological data from Italy because there are no reference centers that follow these patients. The literature data, which come mainly from North America and Asia, speak of a prevalence of 2% in the general population,” Romano stated.

Romano disagreed with the study’s criticism of the current diagnostic criteria. “A patient with CVS has an average of four episodes per year, with the most severe cases having one episode per month. We have also observed patients with two episodes per month, but always with an interval of at least 15 days between each episode. Patients experiencing weekly vomiting are more likely to have chronic vomiting and not CVS,” he explained.

“CVS is a well-characterized clinical condition with both neurological and gastroenterological components,” Romano concluded. Doctors should suspect CVS in patients with recurring vomiting episodes and consult a neurologist as the first step. Neurologists and gastroenterologists should collaborate to rule out other potential causes and ensure an accurate diagnosis.

This story was translated fromUnivadis Italy using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.