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Developmental Abnormalities of the Genitourinary System

Key Points A voiding cystourethrogram should be performed in infants with high-grade hydronephrosis or bilateral hydronephrosis. Vesicoureteral reflux is more common in male infants and has a high rate of spontaneous resolution. Bladder exstrophy repairs are currently delayed to 3 months of age and performed with a dedicated team. Nadir creatinine predicts future renal function in posterior urethral valves. Current American Urological Association guidelines do not…

Developmental Abnormalities of the Kidneys

Key Points Kidney malformations account for 20% to 30% of all prenatally diagnosed developmental anomalies and are responsible for 31% of all childhood end-stage kidney disease. Patients with unilateral kidney agenesis are at risk for hypertension in childhood and chronic kidney disease in adulthood. Multicystic dysplastic kidney typically presents as a collection of large kidney cysts on ultrasound, and patients generally do well. Autosomal recessive polycystic…

Renal Development

Key Points Renal organogenesis is a complex interaction between gene stimulation of planned growth and complementary apoptosis, allowing appropriate development of the functioning renal organ system, vascular bed, and intertwined genital system. The renin-angiotensin system (RAS) is critical to normal renal development through delicate interaction between the maternal–placental RAS and the developing fetal RAS, which has central hormone-specific and sex-specific configurations that help the developing vascular…

Congenital Malignant Disorders

Key Points The spectrum of malignancies in neonates differs from that in children. Malignancies in neonates are often associated with a genetic predisposition. Neuroblastoma and leukemia are the most common malignancies in neonates. Cancer treatment in neonates poses unique challenges, including the likelihood of significant late effects. Congenital solid tumors are often diagnosed in utero by ultrasonography. Neonatal malignancies differ in incidence, clinical behavior, and heritable…

Neonatal Hyperbilirubinemia and Kernicterus

Key Points Early clinical jaundice or rapidly developing hyperbilirubinemia is often a sign of hemolysis, the differential diagnosis of which commonly includes immune-mediated disorders, red cell enzyme deficiencies, and red cell membrane defects. Knowledge of the maternal blood type and antibody screen is critical in identifying non-ABO alloantibodies in the maternal serum that may pose a risk for severe hemolytic disease of the newborn. Knowledge of…

Neonatal Leukocyte Physiology and Disorders

Key Points The neonate and the young infant depend primarily on the innate immune system for host defense. With limited prior exposure to infectious and environmental antigens, the adaptive immune arm is still in a phase of structural and functional development. Neutropenia is frequently encountered during the neonatal period. Neonatal neutrophils show a wide range of functional deficiencies in movement, phagocytosis, and microbial killing. With the…

Neonatal Transfusion

Key Points Recent multicenter randomized trials support more conservative transfusion approaches with the use of lower hemoglobin and platelet count thresholds. Two multicenter clinical trials did not show improvement in survival without neurodevelopmental impairment or other important outcomes with the use of higher hemoglobin thresholds for red blood cell transfusion in preterm infants. Given the lack of benefit, these data generally support the use of a…

Neonatal Erythrocyte Disorders

Key Points Erythropoiesis occurs in stages or waves during embryonic development, initiating in the yolk sac, migrating to the liver, and finally to the bone marrow. The sites of erythropoietin production also transition during development from the neuronal cells to the fetal hepatocytes, and ultimately to the renal fibroblasts. Fetal red blood cells (RBCs) have higher mean corpuscular volumes and mean corpuscular hemoglobins, different hemoglobin composition,…

Neonatal Platelet Disorders

Key Points The most common cause of mild to moderate, early-onset thrombocytopenia in well-appearing neonates is placental insufficiency, frequently manifesting as small-for-gestational status at birth. This thrombocytopenia resolves spontaneously, usually within 10 days, and carries good prognosis. Thrombocytopenia in sick infants is usually associated with sepsis or necrotizing enterocolitis (NEC) and requires prompt intervention. Neonates with platelet counts <50 × 10 9 /L in the first…

Neonatal Bleeding and Thrombotic Disorders

Key Points Acquired or inherited coagulation disorders should be considered in any neonate that suffers significant hemorrhage. Treatment for specific coagulation disorders should be provided in consultation with pediatric hematology and based on the most current guidelines. Thromboembolism (TE) is a significant problem affecting both term and preterm neonates. Most neonates that experience a significant TE event have acquired risk factors and/or a prothrombotic disorder. Proper…

Developmental Hematology

Key Points Pluripotential stem cells sustain hematopoietic function throughout a person's lifetime; the fate of developing cells is influenced by the microenvironment. The site of erythropoiesis changes over development, progressing from the yolk sac to the aortogonadomesonephron, to the liver, and then to the bone marrow. Erythropoietin (Epo) is the principal factor regulating secondary erythropoiesis. Hemoglobin tetramers change over development. Oxygen affinity decreases as hemoglobin switches…

Disorders of the Liver

Key Points Early onset (<24 hours of age) or new jaundice is never normal and should be investigated. Initial evaluation of a jaundiced infant should always include conjugated and unconjugated bilirubin levels. Infants presenting with jaundice secondary to conjugated hyperbilirubinemia should undergo expedient evaluation for potentially life-threatening and treatable causes of cholestasis and then for other causes. Neonatal Liver Disease The liver is the largest abdominal…

Necrotizing Enterocolitis and Short Bowel Syndrome

Key Points What we have termed “necrotizing enterocolitis” (NEC) is not a discrete entity but, rather, a manifestation of different forms of intestinal injury that can lead to intestinal necrosis. To make progress in terms of prevention, a better delineation of these forms of injury is critical. The pathophysiology of the classical form of NEC involves an interaction of factors that include an immature bowel and…

Neonatal Gastroesophageal Reflux

Key Points Gastroesophageal reflux (GER) is almost universal in neonates. It is a physiologic process secondary to frequent spontaneous transient lower esophageal sphincter relaxation, relatively large volume liquid diet, and age-specific body positioning. Preterm infants have relative immaturity of neural control of the gastrointestinal tract, leading to delayed gastric emptying and slow gut motility. The diagnosis of GER in the neonatal intensive care unit (NICU) is…

Abdominal Wall Defects

Key Points Gastroschisis is a congenital abdominal wall defect located just to the right of the umbilicus. The bowel that herniates out of the abdomen is not covered by a membrane. Fetuses and newborns with a gastroschisis have a low risk of associated anomalies, except for a 10% to 25% risk of intestinal atresia. The clinical outcomes of patients with gastroschisis are mainly determined by their…

Structural Anomalies of the Gastrointestinal Tract

Key Points Small inclusion cysts in the oral cavity are common in newborns and almost always resolve without treatment. Suspect the diagnosis of esophageal atresia when there is feeding difficulty with an inability to pass a tube from the nose (or mouth) into the stomach. In the most common type of esophageal atresia, there is a fistula from the trachea to the distal esophagus (tracheoesophageal fistula…

Parenteral Nutrition for the High-Risk Neonate

Key Points Early use of parenteral nutrition in the very low birth weight (VLBW) neonate minimizes nutrient store losses and improves growth outcomes. Initial support goals include glucose infusion of 4 to 8 mg/kg/min, amino acids at 2 to 3 g/kg/day, and lipids at 2 g Goal calorie intake for full parenteral nutrition for VLBW infants (1000 to 1500 g) is 90 to 100 kcal/kg/day (3…

Enteral Nutrition

Key Points Early protein intake is associated with improved growth and neurodevelopmental outcomes in premature infants; achieving adequate intake requires a combined parenteral and enteral approach. Mother’s own milk (MOM) is the preferred diet for preterm infants; further research is needed to develop evidence-based clinical guidelines to optimize the use of donor human milk when MOM is unavailable. For very low birth weight infants, unfortified human…

Neonatal Seizures

Key Points Neonatal seizures are common. Clinical assessment alone is insufficient for diagnosis, and EEG evaluation is necessary. Seizures are often symptomatic of an underlying cause requiring investigation. Confirmed seizures should be treated with antiseizure medications. Neonatal Seizures Seizures in the neonate occur in 2 to 4 per 1000 live births and are a cause of neonatal morbidity and mortality. Frequently, this onset is a neurologic…

Neonatal Neuromuscular Disorders

Key Points Evaluation of neonatal hypotonia includes neuromuscular conditions, and the diagnostic work-up should be approached in a stepwise manner. A normal creatine phosphokinase does not completely rule out muscle disease. Electromyography is useful in the diagnostic evaluation of hypotonia and weakness. Spinal muscular atrophy (SMA) can present in the neonatal period and has time-sensitive treatments. Genetic testing for the commonly found gene deletion in SMA…