Clinical Pearls & Morning Reports
Published August 2, 2023
Over the past two decades, the incidence of cerebral palsy, particularly severe cerebral palsy, has declined. However, there has been no decline in the high incidence of cognitive impairment and social and emotional challenges among children and young adults born preterm. Read the NEJM Review Article here.
Q: Name the three major forms of recognized brain injury in preterm infants that are associated with subsequent neurodevelopmental impairment.
A: The immature brain is vulnerable to unique forms of injury. Three major forms of recognized brain injury in preterm infants are associated with subsequent neurodevelopmental impairment: white-matter injury, germinal matrix–intraventricular hemorrhage, and cerebellar hemorrhage. Among the injuries affecting the developing preterm brain, white-matter injury is the most prevalent, owing to the exquisite vulnerability of early differentiating preoligodendrocytes.
Q: Are the major forms of recognized brain injury the only source of adverse neurodevelopmental outcomes in preterm infants?
A: Although the major forms of brain injury have adverse neurodevelopmental outcomes, recent recognition of altered brain development in preterm infants has provided a new understanding of key factors during the period spent in the neonatal intensive care unit (NICU) that may modulate this critical phase of rapid brain development, with adverse neurodevelopmental consequences. Thus, not only brain injury but also impaired brain development, due to and potentially independent of injury, contribute to adverse neurodevelopmental consequences in preterm infants.
A: Germinal matrix–intraventricular hemorrhage is the most common form of neonatal intracranial hemorrhage. Despite advances in perinatal care, the incidence has not changed in the past two decades. The importance of such lesions relates not only to their high incidence but also to the gravity of the more severe forms of intraventricular hemorrhage and their attendant complications. Consequences may include destruction of the immature germinal cerebral region, resulting in loss of progenitor cells; compression of terminal veins, which can result in high-grade parenchymal venous hemorrhagic infarction; acceleration of white-matter injury through oxidative stress; and hydrocephalus, which can follow intraventricular hemorrhage and lead to axonal and other injuries.
A: The possibility that dysmaturation of white- and gray-matter structures, whether directly or indirectly related to brain injury, can be counteracted has been suggested by a variety of clinical, epidemiologic, and experimental studies. Factors that may play a role in counteracting dysmaturation include not only the prevention of hypoxia, ischemia, and inflammatory insults but also nutritional support and a variety of experiential factors. Experimental studies suggest that neuronal maturation can be altered by environmental sensory factors, such as auditory and visual input. Historically, the NICU has been a brightly lit environment with excessive noise throughout 24 hours per day of continuous activity. Recent trends in NICU design have led to infants being cared for in single rooms, enhancing privacy for the family and reducing rates of infection. However, both the overstimulation of the historical NICU design and the quiet single-room design may have detrimental effects on brain maturation.