Cyclic Vomiting Syndrome - Diagnostic Criteria and Investigations

Diagnostic Criteria and Investigations

The cause of CVS has not been determined; there are no diagnostic tests for CVS. Several other medical conditions can mimic the same symptoms, and it is important to rule these out. If all other possible causes have been excluded a diagnosis of CVS may be appropriate.

There are established criteria to aid diagnosis of CVS; essential criteria are:

1. A history of three or more periods of intense, acute nausea, and unremitting vomiting and sometimes pain lasting hours to days and even into months are reported.
2. Intervening symptom-free intervals, lasting weeks to months
3. Exclusion of metabolic, gastrointestinal or central nervous system structural or biochemical disease e.g. individuals with specific physical causes (e.g. intestinal malrotation)

Once formal investigations to rule out gastrointestinal or other etiologies have been conducted, these need not be repeated in future episodes.

The prevalence of the condition is not clear. Two published studies on childhood CVS suggest nearly 2% of school age children may have CVS. However, diagnosis is problematic and as knowledge of CVS has increased in recent years more and more cases are emerging. This suggests a tendency to underdiagnosis, and thus the true figure may be higher.