Early diagnosis of neonatal-onset cyclic vomiting syndrome.

Cyclic vomiting syndrome (CVS) is characterized by recurrent episodes of severe vomiting with a completely asymptomatic interictal interval. Relatively few patients develop CVS in the neonatal period, and an early diagnosis is difficult. We experienced an infant who was diagnosed with neonatal-onset CVS in early infancy. An 8-day-old girl was admitted to our neonatal intensive care unit because of frequent vomiting beginning 12 h after birth and weight loss reaching 84.2% of her birth weight. Despite extensive examinations, no abnormalities to explain the vomiting were found. She continued to vomit, and a cyclical pattern with a vomiting phase lasting for three days followed by a non-vomiting phase lasting for about one to two weeks became obvious. Based on her clinical course, the family history of migraine and the effectiveness of Phenobarbital, she was diagnosed with CVS at three months old. Although CVS is a diagnosis of exclusion, a family history of migraine can aid its early diagnosis. If the illness is suspected in the neonatal period, diagnostic treatment with Phenobarbital may be considered. The case suggests the need to include CVS in the differential diagnosis of neonates with unexplained repetitive vomiting.