Renal malformations account for 20%–30% of all prenatally diagnosed developmental anomalies and are responsible for 31% of all childhood end-stage renal disease. Patients with unilateral renal agenesis are at risk for hypertension in childhood and chronic kidney disease in adulthood. Multicystic dysplastic kidney typically presents as a collection of large renal cysts on ultrasound, and patients generally do well. Autosomal recessive polycystic kidney disease presents as bilaterally enlarged hyperechoic kidneys, often without cysts, and patients may have significant pulmonary and renal complications. The outcome for patients with renal dysplasia depends significantly on the amount of functioning renal tissue and the associated congenital anomalies. Infant dialysis has improved rapidly over recent years, and 2-year survival outcomes as high as 80% are now reported by multinational dialysis databases.
Congenital heart disease (CHD) is a common birth defect with improved 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 transposition of the great arteries. Fetal MRI studies suggest this delayed development begins in the third trimester. Aberrant fetal physiology resulting in decreased oxygen and substrate supply to the brain may result in these imaging and ND abnormalities in addition to other perioperative risk factors. Children with complex CHD have a prevalence of pervasive but subtle cognitive problems termed the neurodevelopmental signature of complex congenital heart disease.
An understanding of thyroid embryogenesis and the physiology of the thyroid gland in the perinatal period is important for proper interpretation of abnormal laboratory results and initiation of appropriate treatment. Appropriate thyroid hormone function is essential for normal neurodevelopment in infancy and childhood. Hypothyroidism in the first year of life can result in significant deleterious effects on growth and neurologic injury. Delay in treatment of congenital hypothyroidism (CH) is the most common preventable cause of mental retardation. Neonatal screening can provide early diagnosis and can prevent delays in treatment. Newborn screening methods differ and may possibly miss rare forms of congenital hypothyroidism. Eighty-five percent of cases of permanent CH are associated with abnormal development of the thyroid gland. In preterm newborns, thyroid hormone levels may fall because of immaturity of the thyroid gland, but these changes may be exacerbated by complications of prematurity. Thyroid metabolism can be affected by exogenous sources of iodine, dopamine infusions, blood transfusion, and glucocorticoid treatment. The clinical manifestations of Graves disease in the newborn include irritability, flushing, diarrhea, vomiting, tachycardia, hypertension, poor weight gain, thyroid enlargement, and exophthalmos. There is concern for neurologic damage in infants with hemangiomas when hypothyroidism is occult and untreated.
Pregnancies complicated by maternal medical or surgical disorders increase the risk of a suboptimal perinatal outcome. Adverse consequences may result from delays in diagnosis and treatment, as well as effects of the disease process and/or treatment. Fortunately, most diagnostic and therapeutic modalities can be used in pregnancy, but there are important nuances for some such as radiation and medication exposures. How pregnancy affects a medical disorder and conversely a condition effects pregnancy are important issues to address, particularly in those with pre-existing diseases. This chapter addresses some common medical conditions and general principles in evaluation and management.
The preterm brain is susceptible to a broad spectrum of injury that ranges from diffuse nonnecrotic lesions to hemorrhage, to severe necrotic tissue destruction. This chapter addresses three common and frequently overlapping forms of preterm cerebral injury: intraventricular hemorrhage (IVH), white matter injury (WMI), and gray matter injury. The impact of preterm cerebral injury is considerable. Among children born very preterm, even with modern neonatal intensive care, 5% to 10% have major motor deficits, including cerebral palsy related to significant WMI, and more than half have significant cognitive, behavioral, or sensory deficits. Despite a gradual decline in the incidence of most grades of IVH, the increased survival of very low birth weight infants has resulted in an increase in the absolute number of infants with IVH. Cystic WMI is less common in current cohorts but when present is commonly associated with cerebral palsy, cortical visual impairment, and a spectrum of cognitive and learning disabilities. Preterm infants more commonly display diffuse WMI that results in myelination disturbances related to the death of oligodendrocyte progenitors. Diffuse WMI, often reflected in punctate WMI on diagnostic MRI, is linked to a broad spectrum of persistent neurobehavioral disabilities that include impairments in motor and cognitive skills. Chronic diffuse WMI is also accompanied by reduced cerebral gray matter growth that appears to be related to widespread disturbances in neuronal maturation. The spectrum of neurodevelopmental impairments that follow WMI in the preterm neonate are consistent with the dysmaturation in white matter and cerebral gray matter. These recently recognized forms of cerebral gray and white matter dysmaturation present new challenges for diagnosis and suggest new therapeutic strategies.
Many pathologic states in the neonate are associated with disruptions in normal body fluid, electrolyte, and acid–base balance, which at times may in themselves be life threatening. The maintenance of normal fluid, electrolyte, and acid–base balance is a cornerstone of appropriate management of the sick neonate
Owing to their cutaneous, immunologic, and renal immaturity, newborns (especially premature neonates) are at increased risk of infection. As a group of potentially life-threatening but often treatable diseases, infections must always be considered in a newborn with skin lesions. Prompt diagnosis and initiation of therapy are crucial to prevent devastating long-term sequelae, particularly in instances of disseminated disease. Staphylococcus aureus, Streptococcus species, Candida albicans, and herpes simplex virus are the most common causes of skin infections in the neonate.
