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Neonatal Immunity

KEY POINTS 1. The fetal-neonatal immune system becomes activated at birth to play a role in host defense and eliminate environmental pathogens but also to tolerate self-antigens, nutrients, and commensals. 2. The innate immune system is comprised of neutrophils, the monocyte-macrophage lineage, natural killer cells, and the noncytotoxic innate lymphoid cells. 3. Neutrophils are the most numerus subgroup of leukocytes, but unlike in the adult, these…

Treating Neonatal Abstinence Syndrome in the Newborn

KEY POINTS 1. In the United States an infant is born every 15 minutes who will develop symptoms of neonatal abstinence syndrome (NAS); each year, about 32,000 infants are estimated to develop NAS. 2. The exposure of the developing fetus to stimulants, alcohol, cannabinoids, and antidepressant medication can all have a negative impact. To refer specifically to the impact of opioids, the term neonatal opioid withdrawal syndrome…

Management of Myelomeningocele and Related Disorders of the Newborn

KEY POINTS 1. Spina bifida is the most common nonlethal birth defect of the central nervous system and occurs when the vertebral column fails to close, resulting in neurologic impacts from both the abnormal formation and ongoing damage to the exposed nervous tissue. 2. The underlying cause of spina bifida is multifactorial, involving genetic, metabolic, and environmental influences. 3. The Chiari II malformation is classically associated…

Management of Neurotrauma

KEY POINTS 1. Childbirth is a traumatic event; the head of the neonate is subject to multiple forces that, in turn, may result in clinically relevant neurologic injuries. 2. Extracranial scalp traumatic injuries are the most common type of neonatal head trauma. 3. Scalp lesions may hinder the diagnosis of more serious intracranial lesions, such as depressed skull fractures. 4. Intracranial hematomas can be found in…

Intraventricular Hemorrhage and Posthemorrhage Hydrocephalus

KEY POINTS 1. Very-low-birthweight infants are at risk of spontaneous germinal matrix–intraventricular hemorrhages (GM-IVHs). 2. GM-IVHs usually originate within the subependymal germinal matrix lining the ventricles and progress outwards into the ventricles. IVH occurs most frequently during the first 72 hours after birth. 3. A subset of infants with IVH develop periventricular hemorrhagic infarction, posthemorrhagic ventricular dilatation, and posthemorrhagic hydrocephalus (PHH). 4. Posthemorrhagic ventricular dilatation is…

Stroke in Neonates

KEY POINTS 1. Perinatal arterial ischemic stroke most often results from the convergence of multiple stroke risk factors specific to the perinatal period and has a low risk of recurrence. 2. Neonatal arterial ischemic stroke refers to the most common presentation of perinatal stroke when focal seizures or diffuse neurologic signs lead to diagnosis soon after birth. A subset of patients remain undiagnosed in the neonatal…

Neonatal Seizures

KEY POINTS 1. Seizures are very common in the neonatal period and constitute a neurologic emergency. 2. Specific aspects of the physiology of the developing brain make it highly susceptible to hyperexcitability and seizure occurrence. 3. Brain injury often causes or contributes to seizures. Among premature infants, seizures are most often triggered by intraventricular hemorrhage; in term babies, hypoxic-ischemic encephalopathy and stroke are the leading causes…

Management of Encephalopathy of Prematurity

KEY POINTS 1. Encephalopathy of prematurity reflects white and gray matter injury combined with neuronal-axonal abnormalities impacting preterm infants. 2. Key risk factors include hypotension and the need for inotropes, hypoxia, and inflammation. 3. Evaluation of high-risk infants in the neonatal intensive care unit (NICU) includes use of neuroimaging and neurobehavioral assessments such as the General Movements Assessment. 4. Management starts prior to birth and continues…

Management of Hypoxic-Ischemic Encephalopathy Using Measures Other Than Therapeutic Hypothermia

KEY POINTS 1. Neonatal encephalopathy is an alteration in consciousness or neurologic exam in newborn infants. Hypoxic-ischemic encephalopathy accounts for nearly 50% of all cases. 2. Clinical presentation depends on the duration, timing, and severity of the insult and may evolve over the subsequent hours to days. Clinical staging of encephalopathy is usually based on the Sarnat criteria. 3. Disruption of blood flow causes ischemic injury;…

Management of Hypoxic-Ischemic Encephalopathy Using Therapeutic Hypothermia

KEY POINTS 1. A healthy fetus has considerable aerobic and anaerobic reserves to successfully adapt to transient or mild hypoxia. Prolonged or repeated severe asphyxia results in failure of adaptation and progressive hypotension and hypoperfusion. The severity of brain injury is consistently related to the severity and duration of hypotension. 2. There is no intrinsic, physiologic relationship between the amount of systemic anaerobic metabolism (as reflected…

Neonatal Thrombocytopenia

KEY POINTS 1. Platelets are anuclear cellular fragments that are released from megakaryocytes and are involved in primary hemostasis. 2. The normal platelet counts in newborn infants have been traditionally defined as 150 to 450 × 10 9 These counts decline during the early neonatal period but then begin to rise toward the end of the first week. 3. Platelet production involves the production of thrombopoietic factors…

Evidence-Based Neonatal Transfusion Guidelines

KEY POINTS 1. Anemia occurs when the red blood cell (RBC) mass is not adequate to meet tissue oxygen needs. 2. Target hemoglobin and hematocrit have been used as clinical indicators for RBC transfusion in preterm infants with acute and chronic anemia. 3. The minimal target hematocrit or hemoglobin that optimally balances the risks and benefits of transfusion remains unknown because a marker for transfusion need…

Neonatal Anemia

KEY POINTS 1. Anemia is an abnormal, and an unhealthy, reduction in the blood hemoglobin concentration or the hematocrit. There are limitations in our current definitions of anemia, which are based on “reference intervals” constructed from clinically obtained laboratory tests, not from tests performed on healthy volunteers. 2. Erythropoietin is the main physiologic regulator of red blood cell (RBC) production. 3. Neonatal RBCs frequently show morphologic…

A Practical Guide to Evaluating and Treating Severe Neonatal Indirect Hyperbilirubinemia

KEY POINTS 1. We still need a universally accepted definition of severe hyperbilirubinemia; no particular thresholds of unconjugated or total bilirubin levels have been definitively associated with acute or chronic bilirubin encephalopathy. 2. Several measurements can be useful for the assessment of hemolysis, such as those of end-tidal carbon monoxide, blood levels of analytes such as carboxyhemoglobin and haptoglobin, reticulocyte percent and number, cell-free hemoglobin, and…

Hemodynamic Assessment and Management of a Critically Ill Infant

KEY POINTS 1. Shock is a clinical condition marked by poor tissue perfusion resulting in inadequate oxygen delivery and tissue hypoxia. 2. Neonates with shock have hypotension or poor tissue perfusion, and there are important surrogate markers such as prolonged capillary refill time, low urine output, and lactic acidosis. 3. Early neonatal hypotension seems to increase the risk of brain injury and intraventricular hemorrhage. 4. Current…

Pulmonary Hypertension in Chronic Lung Disease

KEY POINTS 1. Pulmonary hypertension (PH) in young infants is defined as a resting mean pulmonary artery pressure (mPAP) ≥20 mm Hg. 2. The mPAP at birth resembles the systemic blood pressure and then drops to infrasystemic levels over the first few days. However, many infants develop pathologic structural/functional changes in the pulmonary circulation due to lung injury and develop PH. 3. Prematurity-related bronchopulmonary dysplasia (BPD)…

Neonatal Arrhythmia and Conduction Abnormalities

KEY POINTS 1. The normal cardiac electrical signal travels from the atria to the ventricles through a conduction system comprised of the sinus node, atrioventricular (AV) node, His bundle, and Purkinje system. 2. The AV node normally regulates the electrical action potentials from the atria to the ventricles. In some instances, the electrical signal bypasses the decremental AV node via an accessory pathway. AV block is…

Medical and Surgical Management of Critical Congenital Heart Disease

KEY POINTS 1. The natural history of congenital heart diseases (CHDs) varies tremendously. Some critical CHDs become symptomatic and require therapeutic intervention in the neonatal period. 2. Patients with CHDs that result in inadequate pulmonary blood flow typically demonstrate cyanosis within minutes of life that does not improve with the administration of oxygen. Many of these patients need treatment with a prostaglandin infusion (PGE1) while awaiting…

Cardiac Defects—Anatomy and Physiology

KEY POINTS 1. Congenital heart diseases (CHDs) are an important cause of morbidity and mortality in young infants. These malformations account for approximately 300,000 deaths yearly. 2. Cardiac septal defects are the most common type of anomalies. Ventricular septal defects (VSDs) are seen most frequently, in 5 to 50 per 1000 live births. Atrial septal defects (ASDs) also common and account for 8% to 10% of…