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Congenital Malformations of the Central Nervous System

Key Points Brain malformations are a significant source of morbidity and death in neonates. Advances in imaging and genetics now allow more specific diagnoses. Early and specific diagnosis allows more precise prognostication, including improved monitoring for complications and treatment decisions. Early diagnosis and management of patients with brain malformations require multidisciplinary team management. Prosencephalic Cleavage and Related Events Normal Prosencephalic Development The prosencephalon refers to the…

Central Nervous System Development

Key Points The brain of the preterm and term newborn infant is actively developing, with several key steps occurring during the third trimester, such as the end of neuronal migration, programmed cell death, the generation of axons and dendrites, and the first wave of synaptogenesis. These processes are controlled by genetic programs but are also very sensitive to environmental factors. Epigenetic mechanisms appear to play a…

Long-Term Neurologic Outcomes in Children With Congenital Heart Disease

Key Points Congenital heart disease (CHD) is a common birth defect with continually improving survival of neonates with complex lesions requiring heart surgery. Neurodevelopmental (ND) abnormalities are common in school-age children and adolescents after neonatal heart surgery. Magnetic resonance imaging (MRI) studies have demonstrated evidence of brain injury and delayed brain development, even before having a corrective operation, in patients with hypoplastic left heart syndrome and…

Perinatal Arrhythmias

Key Points The term supraventricular tachycardia (SVT) encompasses several different arrhythmias that may have different diagnostic and therapeutic requirements. Tachycardia mechanisms may be caused by conduction reentry, enhanced automaticity, or triggered automaticity. Isolated atrial and ventricular ectopy is common in the fetus and neonate and usually does not require any therapy. Congenital forms of complete heart block may result in slow heart rates but may not…

Patent Ductus Arteriosus in the Preterm Infant

Key Points Clinical signs of a symptomatic patent ductus arteriosus (PDA) usually appear later than echocardiographic signs and are related to the degree of left-to-right ductal shunting. Factors known to play a prominent role in regulation of ductal patency involve those that promote constriction (oxygen, endothelin, calcium channels, catecholamines, and Rho kinase) and those that oppose it (intraluminal pressure, prostaglandins, nitric oxide, carbon monoxide, potassium channels,…

Persistent Pulmonary Hypertension

Key Points Persistent pulmonary hypertension of the newborn (PPHN) can occur with parenchymal lung disease, with pulmonary hypoplasia, or without associated lung disease ( idiopathic ) and has an incidence of 0.2% in term infants and up to 2% in preterm infants. Maternal factors such as diabetes, high body mass index, smoking, use of selective serotonin receptor inhibitors or nonsteroidal anti-inflammatory drugs, and cesarean delivery increase…

Cardiovascular Compromise in the Newborn Infant

Key Points It is difficult to diagnose neonatal shock in its uncompensated phase during the immediate transitional period, while it is even harder to diagnose neonatal shock in its compensated phase using standard clinical monitoring and clinical approach. It is unclear what gestational- and postnatal-age-dependent blood pressure and systemic and organ blood flow values represent hypotension and poor tissue perfusion (respectively), warranting timely intervention in the…

Developmental Biology of the Heart

Key Points The heart forms from cardiac mesoderm as a symmetric linear tube with connections to the primitive arterial and venous systems. The heart tube is formed by 3 weeks’ gestation in the human. The heart tube loops, establishing laterality, and undergoes septation into four chambers with connections to the systemic and pulmonary arteries and veins. The heart is fully formed by 9 weeks’ gestation. External…

Anatomic Disorders of the Chest and Airways

Key Points Prompt diagnosis and early intervention are key in salvaging infants with life-threatening surgical disorders of the airway and chest. Improved prenatal ultrasound has shifted the diagnosis and management of disorders of the chest and airways into the fetal period. Increased utilization of video-assisted thoracoscopic surgery for congenital thoracic lesions has made surgical intervention on the infant chest less invasive and more tolerable. Anomalies of…

Chronic Neonatal Respiratory Disorders

Key Points Bronchopulmonary dysplasia (BPD), as determined near term corrected age in former preterm newborns < 32 weeks’ gestational age is a marker for chronic respiratory morbidity. Newborns that are most immature and those born from an adverse intrauterine environment, affected by maternal vascular disorders and decreased intrauterine growth, are most susceptible to early neonatal respiratory illness. Early neonatal respiratory illness, marked by increased exposure to…

Acute Neonatal Respiratory Disorders

Key Points Marked hypoxemia in the newborn can be caused by parenchymal lung disease, pulmonary vascular disease, or congenital heart defects. Events occurring at delivery, as well as the response to supplemental oxygen and to continuous positive airway pressure, can provide important clues to the pathophysiology of hypoxemic respiratory failure in the newborn. The echocardiogram has become a vital tool in the clinical management of newborns…

Control of Breathing

Key Points Apnea of prematurity is universal in preterm infants and a manifestation of greater inhibitory (rather than excitatory) influences on the central respiratory network. In premature infants, excitation of peripheral arterial chemoreceptors by hypoxia predisposes to periodic breathing and the hypoxic ventilatory response is not sustained. The protective upper airway reflex (laryngeal chemoreflex) prevents aspiration, but in premature infants, profound bradycardia, apnea, and oxygen desaturation…

Neonatal Respiratory Therapy

Key Points Most neonatal lung diseases are characterized by increased alveolar surface tension causing atelectasis. To offset this, pressure is applied to the upper airway through either noninvasive or invasive techniques. Regardless of the support technique applied, mean airway pressure (mPaw) is a good measure of the amount of support that is applied to offset these surface forces and improve ventilation/perfusion matching and oxygenation. There are…

Neonatal Pulmonary Physiology

Key Points Understanding the movement and maintenance of a volume of gas in and out of the lungs forms the basis of pulmonary physiology. Maintenance of functional residual capacity (FRC) is vital to adequate lung mechanics and gas exchange. There are multiple methods and techniques for measuring respiratory mechanics in healthy newborns and sick infants. However, to be clinically relevant, the results of these measurements must…

Lung Development

Key Points Lung organogenesis is organized into five stages, beginning at embryonic day 25 in humans. The mechanisms of lung organogenesis, including branching morphogenesis, stretch/mechanotransduction, alveolarization, microvascular maturation, and cellular differentiation, depend on transcriptional regulation of cell–cell and cell–extracellular matrix signaling networks. Alveolarization and lung growth are primarily postnatal processes that extend to early adulthood to establish a surface area that matches growing metabolic needs. Disruption…

Healthcare-Associated Infections

Key Points Healthcare-associated infections (HAIs) are important preventable causes of morbidity and death in neonates. Central line–associated bloodstream infections cause the bulk of HAIs in the neonatal intensive care unit; other HAIs include ventilator-associated pneumonias, urinary tract infections, surgical site infections, and nosocomial viral infections. Several modifiable risk factors have been identified for these conditions. Preventive strategies must focus on basic hand hygiene and infection control…

Fungal Infections in the Neonatal Intensive Care Unit

Key Points Fungal infections account for approximately 12% of neonatal late-onset sepsis, with a mortality rate of approximately 32%, and the most important risk factor remains the gestational age at birth. When a lumbar puncture is performed, 10% to 50% of candidemic infants have associated meningitis and a significant percentage of extremely low birth weight (ELBW, BW<1000 g) infants with Candida meningitis have negative blood cultures.…

Congenital Toxoplasmosis, Syphilis, Malaria, and Tuberculosis

Key Points Maternal transmission of Toxoplasma gondii in the first trimester causes the greatest damage to the fetus, while infections later in pregnancy are more readily transmissible to the fetus. No neonate should be discharged from a birth hospital without documentation of maternal syphilis testing. If maternal syphilis testing is positive, adequacy and timing of maternal treatment, comparison of infant and maternal serology, and infant’s examination…

Viral Infections of the Fetus and Newborn

Key Points Viral infections of the fetus and newborn are common problems in neonatology practice. Fetal (congenital) viral infections should be considered in the differential diagnosis of newborns with intrauterine growth retardation, physical examination and laboratory abnormalities, and illness in the newborn period. Perinatal viral infections involve transmission during the birth process and can result in severe neonatal disease both due to high inoculum and relative…

Neonatal Bacterial Sepsis and Meningitis

Key Points Group B streptococcus and Escherichia coli account for most of the cases of neonatal early-onset bacterial sepsis. Prevention of infection by maternal treatment is the main factor accounting for the decreased incidence of early-onset group B streptococcus sepsis but does not affect rates of late-onset group B streptococcus sepsis. Microbiologic blood cultures of adequate volume (at least 1.0 mL) represent the mainstay for the…