A 10-hour-old boy in the newborn nursery has bilious emesis. He was born at 38 weeks gestation by vaginal delivery to a primigravid 39-year-old woman who received no prenatal care. The patient has voided once but has not yet passed meconium. Physical examination shows a hypotonic neonate with a flat face, prominent tongue, low-set ears, and slanted palpebral fissures. The hands are short with incurved fifth fingers, and a large space is present between bilateral first and second toes. The abdomen is soft and without distension, guarding, or rigidity. Auscultation reveals a loud holosystolic murmur most prominent at the left lower sternal border with a precordial thrill. A nasogastric tube is placed, and abdominal x-ray is shown below. In addition to echocardiogram, which of the following is the best next step in this patient?

Question

A 10-hour-old boy in the newborn nursery has bilious emesis.  He was born at 38 weeks gestation by vaginal delivery to a primigravid 39-year-old woman who received no prenatal care.  The patient has voided once but has not yet passed meconium.  Physical examination shows a hypotonic neonate with a flat face, prominent tongue, low-set ears, and slanted palpebral fissures.  The hands are short with incurved fifth fingers, and a large space is present between bilateral first and second toes.  The abdomen is soft and without distension, guarding, or rigidity.  Auscultation reveals a loud holosystolic murmur most prominent at the left lower sternal border with a precordial thrill.  A nasogastric tube is placed, and abdominal x-ray is shown below.  In addition to echocardiogram, which of the following is the best next step in this patient?

Quizplus · Accepted Answer

11ec25c8_d682_4088_bc81_31ff2eb81593_MD0003_00 This neonate has dysmorphic features characteristic of Down syndrome (trisomy 21). The most common gastrointestinal anomaly associated with Down syndrome is duodenal atresia. dysmorphic features Duodenal atresia classically presents with bilious vomiting in the first 2 days of life. Abdominal distension is absent because gas cannot pass the duodenum. Prenatal ultrasound shows polyhydramnios due to inability to swallow and remove amniotic fluid. X-ray shows air trapped in the stomach and proximal duodenum ("double bubble" sign) with no distal intestinal gas. Management includes discontinuing enteral feeds, nasogastric tube decompression, and surgical repair. A preoperative echocardiogram is required because 50% of patients with Down syndrome have congenital heart disease, especially ventricular and/or atrial septal defects. This patient's holosystolic murmur is characteristic of ventricular septal defect. (Choices A and D) Down syndrome is associated with Hirschsprung disease (HD), the evaluation of which includes barium enema and rectal biopsy. HD can cause bilious emesis, delayed passage of meconium (age >48 hours), and abdominal distension. However, because the obstruction is distal, x-ray would show dilated loops of small and large bowel. Although this 10-hour-old infant is not expected to have passed meconium yet, his x-ray with a double bubble sign is classic for duodenal atresia. dilated loops of small and large bowel (Choice B) A karyotype confirms trisomy 21 but is not urgent in this child with characteristic dysmorphic features and signs of duodenal atresia. (Choice C) Pyloric ultrasound diagnoses pyloric stenosis, which presents with postprandial, nonbilious emesis at age 3-6 weeks, making this diagnosis unlikely. (Choice F) Sweat testing for cystic fibrosis is necessary for any neonate with meconium ileus. Meconium ileus causes delayed passage of meconium, marked abdominal distension, and sometimes bilious emesis. X-ray shows dilated loops of small bowel due to terminal ileum obstruction (not seen in this case). Meconium ileus is not associated with Down syndrome. dilated loops of small bowel (Choice G) Upper gastrointestinal (UGI) series is sometimes included in the workup of duodenal atresia but is not necessary if the x-ray is diagnostic, as in this case. Although UGI is the gold standard for diagnosing malrotation, which can also cause bilious emesis, malrotation presents with abdominal distension and distal intestinal gas on x-ray. Educational objective: Duodenal atresia is strongly associated with Down syndrome and presents with bilious vomiting in the first 2 days of life and a "double bubble" sign on abdominal x-ray. Treatment is surgical repair. References: Associated congenital anomalies among cases with Down syndrome. (http://www.ncbi.nlm.nih.gov/pubmed/26578241) Congenital duodenal obstruction in neonates: a decade's experience from one center. (http://www.ncbi.nlm.nih.gov/pubmed/25124975)

A 10-Hour-Old Boy in the Newborn Nursery Has Bilious Emesis