Cyclic vomiting syndrome: Future clinical and research priorities for: Special supplement/proceedings of 3rd international symposium.

Background: An increasing number of studies have explored the clinical features, epidemiology, pathophysiology, and management of cyclic vomiting syndrome (CVS). CVS is common in adults and children and negatively impacts patients, families, and the healthcare system. A related condition, cannabinoid hyperemesis syndrome (CHS), has been a focus of interest in the lay press and published literature.

Purpose: Clinical presentations of CVS have been defined by small series and expert opinion, but recent prospective studies are refining our understanding of the spectrum of emetic episodes and the breadth of comorbid conditions. Large cross-sectional population analyses are clarifying CVS prevalence and factors related to age, ethnicity, and geographic region. CVS pathophysiology is multifactorial with contributions from migraines, dysautonomia, endogenous cannabinoids, mitochondrial dysfunction, genetic abnormalities, and rapid gastric emptying. CVS treatment relies on antiemetics and antimigraine therapies to abort acute episodes coupled with prophylactic regimens employing neuromodulators and antiepileptics. CHS represents a challenge partly because of difficulties in achieving sustained cannabis abstinence. Benefits of other therapies in CHS remain poorly defined. Several areas warrant further scrutiny including better identification of CVS triggers and characterization of different CVS subsets including those with frequent severe episodes, refined description of epidemiology to allow targeting of populations predisposed to CVS development, rigorous definition of pathogenic factors to provide a foundation for exploratory studies of novel therapies, and conduct of controlled trials by multicenter collaborations to confirm benefits of existing and new therapies in development. Progress in these areas will be facilitated by generous governmental and industry support.