Cyclical Vomiting Syndrome in Children: Potential Role of Electroencephalogram in the Diagnostic Evaluation

Abstract

Aim: Cyclical Vomiting Syndrome (CVS) is a functional disorder in childhood which is increasingly being recognized. The pathogenesis of CVS remains unknown but there appears to be a link between CVS and migraine, suggestive of a central aetiology. We aimed to determine the utility of electroencephalograms (EEG) in the diagnostic algorithm of a child suspected to have CVS. Methods: We conducted a retrospective review of children who have been diagnosed with CVS in our unit since 1999 when EEGs were performed as part of the diagnostic evaluation. Results: There were 48 children with recurrent vomiting in whom the clinical diagnosis of CVS was entertained. Median age of onset was 4 years (6 months-12 years). Of the 48 patients, 27received a final diagnosis of CVS/abdominal migraine, following normal investigations which included abdominal x-ray, barium study, abdominal ultrasound and screen for inborn errors of metabolism (IEM); 21 received other diagnosis which included, non-specific abdominal colic (12), hiatal hernia (1), epilepsy (3) and IEM (1). Of the 27 with CVS/abdominal migraine, 21 had EEG features consistent with mild encephalopathy during an acute attack. Twelve of them had a repeat EEG when clinically well, and all but 1 showed normalization. Conclusions: In our series, 78% demonstrated transient electrographic changes of acute encephalopathy during the acute attacks. The use of EEG in the appropriate clinical context may provide additional evidence to support the diagnosis of CVS in patients without other aetiologies for mild acute encephalopathy.