Source: Waisfeld A, Randazzo I, Aronoff S, et al. Etiologies of cyclic vomiting syndrome in children: a systematic review of 1,373 patients. Pediatr Gastroenterol Hepatol Nutr. 2026;29(1):62-70; doi: 10.5223/pghn.2026.29.1.62.Investigators from Lewis Katz School of Medicine, Temple University, and St Christopher’s Hospital for Children, both in Philadelphia, conducted a systematic review to characterize the differential diagnosis of cyclic vomiting syndrome (CVS) in children. For the review, they identified studies that included at least 10 children ≤18 years old with CVS. Only studies for which the definition of CVS met Rome IV (or equivalent) criteria were selected. Specifically, the Rome IV criteria include ≥3 episodes of vomiting with acute onset and duration <1 week within the prior year, with ≥2 episodes in the last 6 months. For the selected studies, the authors identified the diagnoses of the included pediatric patients with CVS. They then collated these diagnoses into broad 'triggers' that each included multiple diagnoses or specific individual diagnoses. Data from all the selected studies were pooled, and the overall proportion and 95% credible interval (CredI) of each trigger and diagnosis that was an etiology for CVS was determined.A total of 17 studies were included in the systematic review. Five of the studies were from the US. There were 1,373 pediatric patients in the selected studies, and a total of 1,415 triggers and diagnoses were described (some children had multiple triggers/diagnoses). The most commonly identified triggers and diagnoses were: psychological stress (26.2% of cases; 95% CredI, 24, 28.5), infection (22%; 95% CredI, 19.9, 24.2), motion sickness (19.3%; 95% CredI, 17.3, 21.4), and migraine (12.9%; 95% CredI, 11.2, 14.7). Among patients with a psychological stress trigger, 62.3% had a diagnosis of 'other psychological stress,' 22.9% had environmental stress, 6.2% had generalized anxiety disorder, and 3% had a major depressive disorder. Sinus infection accounted for 74% of the diagnoses in children with an infection trigger for CVS, followed by upper respiratory tract infection (10%) and travel sickness (7%). Surgical causes of CVS were uncommon, accounting for 3.5% (95% CredI, 2.6, 4.6) of triggers and diagnoses. For patients with a surgical cause trigger for CVS, 46% had a malrotation, and 24% had a post-surgery etiology. Only 0.3% (95% CredI, 0.1, 0.6) of children had a mitochondrial disorder as a cause of their CVS.The authors conclude that multiple triggers and diagnoses were associated with CVS, with psychological stress, infection, and motion sickness being the most common triggers.Dr Yimlamai has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.Episodes of CVS can be disabling to the patient and family, leading to recurrent ED visits and hospitalization. Classically, patients present with severe nausea and repeated episodes of vomiting leading to severe dehydration and at times electrolyte abnormalities.1 Approximately 1.9% to 2.3% of children have CVS, making it a relatively prevalent diagnosis.2 Even mild episodes of recurrent nausea and vomiting (N/V) may prompt families to request an extensive work-up from their pediatrician for the cause of these episodes. Usually there are intervals of quiescence between episodes, which make the CVS episodes even more disruptive to families due to their unpredictability. The dramatic clinical presentation of CVS and prolonged hospitalization of such children to rehydrate and normalize their electrolyte disturbances often prompts an extensive medical evaluation with CVS, typically a diagnosis of exclusion.3 Understanding of common and uncommon causes of recurrent episodes of severe N/V is useful to the pediatrician in considering a work-up for these events. In addition, an awareness of the patient and family of the CVS diagnosis can facilitate their care.The current systematic review to document the frequency of various causes of severe N/V is particularly instructive for primary care pediatricians. The most common causes of CVS include psychologic or environmental stress and infections. It often is advised that pediatricians should consider potential surgical (ie, intestinal malrotation, surgical adhesions), seizures, or mitochondrial disorders as causes of severe N/V.2 The frequency of these causes is relatively low and can be difficult to evaluate if undertaken after the episode has subsided. After CVS patients are stabilized, a careful history and an understanding of the frequency of causes of severe N/V can guide a thoughtful medical evaluation.Common CVS triggers can often be elicited by a careful medical history. Evaluation for rare but serious causes of CVS may require biochemical or radiologic testing.
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