National Digestive Diseases
Information Clearinghouse (NDDIC)
What is cyclic vomiting syndrome (CVS)?
CVS is characterized by episodes or cycles of severe nausea and vomiting that last for hours, or even days, that alternate with intervals with no symptoms. Although originally thought to be a pediatric disease, CVS occurs in all age groups. Medical researchers believe CVS and migraine headaches are related (see CVS and Migraine).
Each episode of CVS is similar to previous ones, meaning the episodes tend to start at the same time of day, last the same length of time, and occur with the same symptoms and level of intensity. Although CVS can begin at any age, in children it starts most often between the ages of 3 and 7.
Episodes can be so severe that a person has to stay in bed for days, unable to go to school or work. The exact number of people with CVS is unknown, but medical researchers believe more people may have the disorder than commonly thought. Because other more common diseases and disorders also cause cycles of vomiting, many people with CVS are initially misdiagnosed until other disorders can be ruled out. CVS can be disruptive and frightening not just to people who have it but to family members as well.
The Four Phases of CVS
CVS has four phases:
- Symptom-free interval phase. This phase is the period between episodes when no symptoms are present.
- Prodrome phase. This phase signals that an episode of nausea and vomiting is about to begin. Often marked by nausea—with or without abdominal pain—this phase can last from just a few minutes to several hours. Sometimes, taking medicine early in the phase can stop an episode in progress. However, sometimes there is no warning; a person may simply wake up in the morning and begin vomiting.
- Vomiting phase. This phase consists of nausea and vomiting; an inability to eat, drink, or take medicines without vomiting; paleness; drowsiness; and exhaustion.
- Recovery phase. This phase begins when the nausea and vomiting stop. Healthy color, appetite, and energy return.