Cyclic Vomiting Syndrome and Functional Vomiting in Adults

Purpose: Cyclic vomiting syndrome (CVS) is characterized by stereotypical and severe episodes of vomiting separated by symptom-free intervals. Based on expert opinion, patients with stereotypical vomiting are considered to differ from those with functional vomiting (FV), and hence Rome III criteria for FV and CVS differ. However, empirical data supporting this differentiation are lacking. Our aim was to evaluate whether clinical or gastric emptying data discriminate patients labeled as having CVS from FV. Methods: The medical records of patients diagnosed with any vomiting (including CVS, FV) over a 13-year period (1993-2006) at our institution were carefully reviewed. Patients with significant conditions that could lead to vomiting were subsequently excluded from the analysis (e.g., previous abdominal surgery, diabetes, on medications that may affect gastric motility, etc.). Gastric emptying was performed by scintigraphy (99mTc-egg meal). Ascertainment of cannabis used was performed by abstraction of a standardized questionnaire included in the medical record. CVS was defined as recurrent, self-limited, stereotypical episodes of vomiting with no identifiable organic disease. FV was defined as recurrent, unexplained vomiting at least once per week that was not cyclical. The associations of clinical factors with patient status (CVS vs. FV) were analyzed using logistic regression models, adjusting for age and gender. Results: A total of 82 patients with CVS and 62 FV patients were identified. The mean (±SD) age of CVS was 30 (±11) years and 40% were female; the mean age of FV was 36 (±13) years and 61% were female (OR for CVS in females relative to males=0.4 [95%CI =0.2, 0.9], p<0.05). There were no significant associations between patient status (CVS vs. FV) and age, BMI, smoking, alcohol use, corresponding symptoms (nausea, abdominal pain, diarrhea, or headache), or gastric emptying (among patients who underwent GE, table 1). Cannabis use was unknown in 19 (13 CVS, 6 FV) and among users (n=33), 27(82%) were CVS giving an overall odds ratio of 4.0 (95% CI 1.5 to 11.2) for CVS in those using cannabis relative to those not, adjusted for age and gender. However gender was confounded with cannabis use, and the OR for CVS was significantly increased only in males using cannabis (OR=5.5, p<0.05, relative to male non-users), but not in females using cannabis (OR=2.5, p=0.25, relative to female non users). Conclusion: CVS (vs. FV) was not associated with clinical factors, but was associated with gender and cannabis use, though these factors are not independent.Table: Distribution of gastric emptying in patients with CVS vs. FV