Bilious vomiting does not rule out infantile hypertrophic pyloric stenosis.

OBJECTIVE: To describe the incidence of bilious vomiting in infants with infantile hypertrophic pyloric stenosis that presented to a pediatric emergency department.

METHODS: A retrospective medical record review included all infants who presented to our level 1 pediatric emergency department from January 1, 2005, through December 31, 2009, who were diagnosed intraoperatively with infantile hypertrophic pyloric stenosis. Emesis was determined to be bilious if the vomit was described as "green," "containing bile," or "bilious."

RESULTS: The authors identified 354 infants with infantile hypertrophic pyloric stenosis. The median age was 4 weeks 6 days (range = 11 days to 13 weeks). Bilious emesis was encountered in 1.4% (5/354; 95% confidence interval = 0.5% to 3.2%). The pyloric thickness measurements on ultrasound were significantly smaller in those with bilious emesis compared with those without bilious emesis (z score = 2.64; P = .014).

CONCLUSION: Bilious emesis was the presenting symptom in a small proportion of infants with infantile hypertrophic pyloric stenosis.