Cyclic vomiting syndrome, or cyclical vomiting syndrome, (CVS) is a chronic functional condition of unknown cause characterized by recurring attacks of intense nausea, vomiting, and sometimes abdominal pain, headaches, or migraines and prostration with no apparent cause. CVS typically develops during childhood but it may persist into adult life. Vomiting occurs at frequent intervals for hours or days. The episodes tend to be similar to each other in symptoms and duration and are self-limited with return of normal health between episodes.
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