This free iTunes segment is just one tiny snippet of the fully-loaded 3-hour monthly Peds RAP show. Earn CME on your commute while getting the latest practice-changing peds information: journal article breakdowns, evidence-based topic reviews, critical guideline updates, conversations with experts, and so much more. Sign up for the full show at hippoed.com/PEDSRAPPOD. Sol Behar, MD, and Jason Woods, MD discuss the evaluation and management of bilious emesis in a neonate.  Bilious emesis in an infant should be treated as an emergency because this is often a symptom of obstruction due to intestinal atresia or midgut volvulus. Causes of intestinal obstruction that present during the neonatal period include: Malrotation with or without volvulus Intestinal atresia Hirschsprung disease Intussusception (rare in the neonatal period) Necrotizing enterocolitis  Malrotation with volvulus. In this condition, the cecum is abnormally positioned in the right upper quadrant and this abnormal positioning predisposes the intestine to twist on its mesentery resulting in volvulus. This causes acute small bowel obstruction and ischemia.  An upper GI, the gold standard for diagnosing or evaluating malrotation, classically shows a duodenum with a "corkscrew" appearance. Intestinal atresia. This is a term used to describe a complete blockage or obstruction anywhere in the intestine. Approximately 30% of infants with duodenal atresia have a chromosomal anomaly, most typically Down syndrome. The "double bubble" sign is caused by dilation of the stomach and proximal duodenum and strongly suggests duodenal atresia Hirschsprung disease. This is a disorder of the motor innervation of the distal intestine that leads to a functional obstruction. In Hirschsprung, the nerves that allow the relaxation of the smooth muscle within the intestine wall are missing, so the area that is affected is constricted.   A contrast enema can support the diagnosis of Hirschsprung disease. It will often show the presence of a “transition zone” which represents the change from the normal caliber rectum to the dilated colon proximal to the aganglionic region.   For younger kids who have not had time to develop the “transition zone”, the rectosigmoid index, the ratio between the diameter of the rectum and the sigmoid colon, is typically >1 in normal children   Necrotizing enterocolitis. This is a condition characterized by bowel necrosis with associated severe inflammation, bacterial invasion, and dissection of gas into the bowel wall. Pneumatosis intestinalis, a hallmark of NEC, appears as bubbles of gas in the bowel wall. Meconium ileus is caused by the obstruction of the small intestines with inspissated meconium. Approximately 10% of patients with CF present with meconium ileus.