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Congenital anomalies have a wide array of presentations, from almost unnoticeable variations to remarkable dysmorphology. They may be detected at first breath of life or several weeks to months later. The causes of congenital anomalies are also as varied as their presentations. Genetic mutations, toxin-induced syndromes, and mechanical in utero effects drive the majority of anomalies; yet in others, the causes remain unknown.
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The clinical management of all congenital anomalies involves a multidisciplinary approach to the patient. Due to the altered physiology of congenital anomalies, many different specialties including neonatology, critical care, surgery, and genetics work in concert to provide optimal outcomes for each individual patient. This chapter will examine several of the most common congenital anomalies and address their pathology, diagnosis, and management.
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ABDOMINAL WALL DEFECTS
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Gastroschisis and omphalocele are the most common abdominal wall defects in neonates. In the United States, the incidence of gastroschisis has seen a 10- to 20-fold increase over the past 20 years.1 Currently, the incidence of gastroschisis is 1 in 4000 live births while omphaloceles have an incidence of 1 in 4000 live births.1
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During normal fetal development, the gut protrudes from the umbilical ring and then retracts back into the abdominal cavity by the 11th week of gestation.1 When the series of events needed to complete this process fail to occur, abdominal wall defects result. Gastroschisis is not commonly associated with other congenital anomalies, with the exception of localized abnormalities such as intestinal atresia (10% to 28%) and cryptorchidism (up to 15%).1,2
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An omphalocele results from failed growth and fusion of the lateral folds early in gestation. This creates a central defect of the umbilical ring and allows the bowel to remain herniated. Over 50% of patients with omphalocele have associated anomalies, which are usually midline.1 These include cardiac defects (30% to 50% of infants), colonic atresia, imperforate anus, sacral and vertebral anomalies, and genitourinary malformations such as bladder exstrophy or cloacae.1 Syndromes associated with omphalocele include the Pentalogy of Cantrell (sternal cleft; pericardial, cardiac, and diaphragmatic defects), Beckwith-Wiedemann syndrome (macroglossia, macrosomia, and hypoglycemia), and trisomy 13, 15, 18, and 21; chromosomal abnormalities occur in up to one-third of cases.1,2,3
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CLINICAL PRESENTATION
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Patients with gastroschisis are often premature. They commonly present with a defect to the right of the umbilicus and herniation of the abdominal contents through the umbilical ring (Figure 126-1). The bowel is not contained within a sac therefore it is often thickened, with a fibrous peel, due to prolonged intrauterine exposure to amniotic fluid.2 Complications of gastroschisis include intestinal macroglossia, volvulus, stenosis, or atresia.2
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