Cyclic vomiting syndrome

Cyclic vomiting syndrome (CVS) is a chronic functional condition of unknown pathogenesis. CVS is characterized as recurring episodes lasting a single day to multiple weeks. Each episode is divided into four phases: inter-episodic, prodrome, vomiting, and recovery. During the inter-episodic phase, which typically lasts one week to one month, there are no discernible symptoms and normal activities can occur. The prodrome phase is known as the pre-emetic phase, characterized by the initial feeling of an approaching episode but still being able to keep down oral medication. The emetic or vomiting phase is characterized by intense persistent nausea and repeated vomiting, typically lasting hours to days. During the recovery phase, vomiting ceases, nausea diminishes or is absent, and appetite returns. "Cyclic vomiting syndrome (CVS) is a rare abnormality of the neuroendocrine system that affects 2% of children." This disorder is thought to be closely related to migraines and family history of migraines.