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What is CVS?





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The diagnosis of CVS has been difficult because vomiting may be caused by a large number of other disorders that are more common. CVS is usually a diagnosis by exclusion of all other causes. At present there are no diagnostic methods (e.g. no blood or urine tests) that can be used to diagnose the disorder. A diagnosis, or, more correctly, a classification of CVS may take several years to achieve. Many sufferers will undergo numerous tests and sometimes misdiagnoses before their condition is recognised.

Formal criteria for diagnosis are shown below, but these probably omit some very common signs. In some people the intense nausea is the predominant symptom. As will be seen there is no single agreed set of criteria, which serves to highlight the problems in obtaining a diagnosis.

In CVS, the pattern of vomiting is such that at the peak this can be 5-6 times per hour. This is different from vomiting induced by most other causes. Onset of vomiting is most often between 2 am and 8 am. Again, this is unusual in other forms of vomiting.

In 1994, the CVSA UK and USA (with support from Glaxo Wellcome) sponsored a symposium on CVS held in London, UK. During the meeting, a series of criteria were agreed for the formal diagnosis of CVS. In many ways this was a huge step forward in the recognition of CVS and its wider acceptance as a serious health issue. Essential criteria are a requirement for diagnosis. Supportive criteria may strengthen the diagnosis, but not all of the criteria may be apparent in any one individual. Associated signs are features that are more difficult to quantitate but may be associated with CVS. The proceedings of this symposium were published (see References).

Essential Criteria

Supportive Criteria


Stereotypical: each episode similar within individuals as to time of onset, intensity, duration, frequency, and associated symptoms and signs.
Associated Symptoms