A step closer to bridging the knowledge gap in pediatric cyclic vomiting syndrome

Cyclic vomiting syndrome (CVS) is a disorder recognized by recurrent stereotypical episodes of severe vomiting with a return to baseline health in between episodes. Diagnosing CVS remains challenging due to its clinical overlap with other vomiting-related conditions. Several diagnostic criteria (2008 expert consensus North American Society for Pediatric Gastroenterology, Hepatology & Nutrition [NASPGHAN] and Rome IV)1, 2 exist to aid in the diagnosis of pediatric CVS, though none are evidence-based or universally applied. Despite these guidelines, diagnostic ambiguity remains in pediatric CVS, highlighting the need for refined, evidence-based, unified criteria that consider episode frequency, duration, interictal symptoms, treatment response, and comorbid conditions like anxiety and dysautonomia (which are common in children with CVS) ultimately allowing for a smoother transition of care to adult experts for these patients. In this issue of the Journal of Pediatric Gastroenterology and Nutrition, Bujarska et al.3 take an important first step to accomplish this feat, by prospectively examining the clinical features and diagnostic characteristics of pediatric CVS and comparing it to a cohort of children with other vomiting disorders. Within the study cohort (pulled from a tertiary care center with CVS expertise), children with CVS had significantly different vomiting characteristics compared to the non-CVS group. Children with CVS typically experienced more frequent (≥4 episodes/preceding 12 months) and longer stereotypical vomiting episodes (lasting up to 19 h). A high proportion of CVS patients reported inter-ictal symptoms such as headaches, nausea, abdominal pain, and chronic fatigue. This study not only contributes to a better understanding of pediatric CVS but also highlights the need for refined diagnostic criteria based on more quantitative data, allowing for more personalized diagnostic approaches for CVS across the age spectrum. Although the time to diagnosis and genetic differences have been identified between adult and pediatric-onset CVS patients, prior studies have suggested that these two age groups appear to have a similar demographic profile and disease characteristics.4-6 However, while the current pediatric and adult Rome IV CVS criteria emphasize the episodic nature of vomiting with stereotypical episodes and a return to baseline health between episodes, there are notable differences. The adult criteria are stricter in terms of the number of episodes required (at least three episodes in the past year and two episodes in the past 6 months occurring at least 1 week apart) and the duration of vomiting episodes (<1 week), while the pediatric criteria are more flexible, allowing for longer duration (separated by weeks to months between episodes) and fewer episodes overall.7 Further, the adult criteria require no vomiting between episodes, but milder symptoms can be present, while the pediatric criteria focus on return to baseline health but do not specify the absence of vomiting. Bujarska et al.3 contribute to bridging the gap between pediatric and adult CVS, which while similar, have subtle differences that can complicate diagnosis and treatment as patients transition to adult gastroenterologists. The authors propose a diagnostic criterion for pediatric CVS, which more closely aligns with the adult Rome IV criteria facilitating a more seamless transition of care and longitudinal research. Unified criteria can dramatically improve continuity in diagnosis, management, and outcomes by minimizing the confusion that can arise when a patient meets pediatric criteria but may not entirely align with current adult standards. Additionally, as the authors point out, less than half of the CVS cohort met the 2008 NASPGHAN (49%) and 2016 Rome IV (46%) criteria for CVS. While this raises concerns about the potential underdiagnosis of CVS in children based on our current guidelines, it remains unclear how much of the low conformance to the criteria is due to the poor sensitivity of the utilized symptom survey, misunderstanding within the survey questions, and other confounding factors. Further investigation is necessary to determine whether the issue lies with the symptom survey itself or whether a complete overhaul of our current criteria for pediatric CVS is needed. Overall, this study not only contributes to advancing the understanding of the features found in children with CVS but also highlights the need for refined diagnostic criteria that better align with the adult criteria, allowing for a smoother transition from pediatric to adult care for adolescents and young adults with CVS. Future work is needed to establish a more unified and comprehensive diagnostic criteria between NASPGHAN and the pediatric and adult Rome V for CVS across the age spectrum. The authors declare no conflicts of interest.