Once confused with other gastrointestinal disorders, cyclic vomiting syndrome can be diagnosed using specific criteria instead of extensive confirmatory testing.
Cyclic vomiting syndrome (CVS) is characterized by recurrent, severe, stereotypical spells of vomiting between which the patient returns to normal or baseline (eg, if disabled) health.
Since its first description more than a century ago, it remains a disorder of unknown etiology and pathophysiology and is currently classified as functional vomiting disorder.1 However, over the past 2 decades, significant progress in recognizing, understanding, and treating CVS has renewed hope for affected pediatric and adult patients.
The Cyclic Vomiting Syndrome Association, formed in 1993, continues to help affected families through parent support, public education, and support of research.1 Recent research efforts have identified the pathophysiologic roles of autonomic dysfunction, stress, and mitochondrial genetics. Greater recognition has been obtained through published guidelines and the development of treatment centers.
Diagnosing cyclic vomiting syndrome
There are 3 essential diagnostic questions to make a tentative diagnosis of CVS: Has the child had 5 episodes of vomiting or at least 3 episodes over a 6-month period? Does the child return to normal (or to baseline) health in between episodes? And, are the episodes similar in time of onset, duration, and associated symptoms?
If one simply asks whether the child has had other similar prior bouts of "stomach flu," and the parents respond with an unusually high number (5-6 episodes), one should consider the diagnosis of CVS. Other typical symptoms during acute attacks include pallor, lethargy, anorexia, nausea, retching, and abdominal pain. Approximately 80% of patients have a family member with migraine.1 The pace of vomiting at its peak is uniquely severe at once every 10 minutes, on average. If the child meets the NASPGHAN consensus diagnostic criteria for CVS and the results of an upper gastrointestinal (UGI) x-ray to exclude malrotation and basic metabolic screening labs (electrolytes, glucose, blood urea nitrogen, creatinine) are normal, one can initiate empiric therapy (Figure).1,2