A 36-year-old woman comes to the clinic for an ultrasound after an elevated alpha-fetoprotein level was found during a second trimester quadruple screen. The patient has had routine prenatal care since 8 weeks gestation. She has been taking a daily prenatal multivitamin since the first trimester and takes no other medications. She has had 2 prior spontaneous abortions but has no chronic medical conditions. The patient does not use tobacco, alcohol, or illicit drugs. Transabdominal ultrasound reveals a fetus with thickened intestinal loops that are floating free in the amniotic sac. There is also decreased fluid in the amniotic sac, suggestive of oligohydramnios. This patient's ultrasound finding is most likely due to which of the following conditions?

Question

A 36-year-old woman comes to the clinic for an ultrasound after an elevated alpha-fetoprotein level was found during a second trimester quadruple screen.  The patient has had routine prenatal care since 8 weeks gestation.  She has been taking a daily prenatal multivitamin since the first trimester and takes no other medications.  She has had 2 prior spontaneous abortions but has no chronic medical conditions.  The patient does not use tobacco, alcohol, or illicit drugs.  Transabdominal ultrasound reveals a fetus with thickened intestinal loops that are floating free in the amniotic sac.  There is also decreased fluid in the amniotic sac, suggestive of oligohydramnios.  This patient's ultrasound finding is most likely due to which of the following conditions?

Quizplus · Accepted Answer

11ec25c8_d67d_ac9e_bc81_316994abf0ef_MD0003_00 This fetus has gastroschisis, a congenital abdominal wall defect lateral to the umbilicus with herniation of uncovered bowel (ie, free-floating in the amniotic sac). Elevated maternal serum alpha-fetoprotein (AFP) levels occur in patients with gastroschisis because AFP passes through the exposed bowel wall into the amniotic fluid. The combination of free-floating intestines on prenatal ultrasound and an elevated maternal serum AFP is highly sensitive for diagnosis. Gastroschisis is generally an isolated defect. Although patients typically do not have other anomalies, continued exposure of the intestines to amniotic fluid causes chronic inflammation and edema, resulting in intestinal thickening. This inflammation increases the risk of necrotizing enterocolitis and bowel obstruction, which can lead to short bowel syndrome. Nutrients are also lost across the exposed bowel, which can result in fetal growth restriction and oligohydramnios (reduced amniotic fluid). The exposed bowel is covered with sterile saline dressings and plastic wrap immediately after delivery to minimize insensible heat and fluid losses (due to intestinal fluid sequestration). A nasogastric tube is placed to decompress the stomach, antibiotics are administered, and the defect is repaired surgically. (Choice A) Beckwith-Wiedemann syndrome is associated with omphalocele, a midline abdominal wall defect in which herniated abdominal contents are covered by a sac of peritoneum. Additional clinical features include macrosomia and macroglossia. (Choice B) Infants with cystic fibrosis are at increased risk for meconium ileus, an intestinal obstruction due to inspissated meconium. Prenatal ultrasound may show thickened, dilated intestinal loops; however, the abdominal wall is intact and the intestines are not free-floating. (Choice D) Prune belly syndrome is due to a defect in abdominal musculature. Intestinal loops may be seen through the thin abdominal wall (causing the prune appearance) and are covered by skin (not free-floating). (Choice E) Trisomy 21 is associated with umbilical hernia (abdominal wall defect covered by skin) and duodenal atresia (characterized by a "double bubble" and polyhydramnios on ultrasonography). umbilical hernia Educational objective: Gastroschisis is an abdominal wall defect lateral to the umbilical cord insertion site with herniation of uncovered bowel. Gastroschisis is an isolated defect with no associated conditions. Management includes neonatal surgical correction. References: Pediatric abdominal wall defects. (http://www.ncbi.nlm.nih.gov/pubmed/24035087) Gastroschisis: an update. (http://www.ncbi.nlm.nih.gov/pubmed/20686898) Gastroschisis: a review of management and outcomes. (http://www.ncbi.nlm.nih.gov/pubmed/27640608)

A 36-Year-Old Woman Comes to the Clinic for an Ultrasound