Kernicterus

Introduction

Since the time of the Mesopotamia clay tablets and subsequently, in the Old Testament, jaundice has been mentioned. But it was not until the time of Hippocrates that jaundice was related to a pathological condition of the liver.

Presentation

Historically, the term kernicterus refers to an anatomic diagnosis made at autopsy based on a characteristic pattern of staining found in babies who had marked hyperbilirubinemia before they died. Regions of the brain most commonly affected include the basal ganglia, hippocampus, geniculate bodies, and cranial nerve nuclei, such as the oculomotor, vestibular, and cochlear.

Investigations

Because of a resurgence of kernicterus during the 1990s, in the United States, studies suggested that hospital discharge of term infants at 24-48 hours of life was a factor. In a pilot study registry monitoring babies with kernicterus, more than 95% of the cases were discharged from the hospital in less than 72 hours. This has prompted a closer follow-up with repeat bilirubin determinations, as needed clinically within 24-48 hours after hospital discharge. Over the last two decades in the United States, national healthcare organizations led by the Academy of Pediatrics, Centers for Disease Control and Prevention (CDC), and the Joint Commission on Accreditation of Healthcare Organizations have alerted practitioners and hospitals about the reemergence of this devastating disorder and provided management guidelines. These practical guidelines can be tailored for effective use in the treatment of hyperbilirubinemia and kernicterus throughout the world. Hispanic and Asian populations appear to have a greater propensity to develop hyperbilirubinemia. However, this does not always translate into the development of kernicterus. Some researchers believe the inclusion of the inherited forms of newborn hemolytic disease into the newborn metabolic screen may assist in identifying a newborn at risk for hyperbilirubinemia and kernicterus, such as glucose- 6- phosphate dehydrogenase deficiency. It is not clear whether knowledge of this condition would change immediate outcomes in the newborn period.

Treatment

Presently there is sufficient and direct laboratory and clinical literature that the use of phototherapy and/or exchange transfusion used in infants with excessive

hyperbilirubinemia can prevent extreme hyperbilirubinemia and kernicterus. And in infants with acute bilirubin encephalopathy, exchange transfusion (with and without phototherapy) can prevent or minimize the chronic sequelae of bilirubin-induced dysfunction. It also should be clear that there are fundamental behaviors needed to avoid the risk of hyperbilirubinemia. The purpose should not be to blame but to establish a safety culture. Performance of root-cause studies leading to the implementation of changes or reinforcing safe and effective behavior should be undertaken in the future. Defined behaviors should be driven by considerations that are not financial. Instead, they should be focused on commitment and should be universal, despite the cost pressures, liability constraints, and resistance to change. We must also respond adequately to the concerns of parents regarding the evolution of neonatal jaundice, poor feeding, breastfeeding difficulties, or changes in behavior or activities of the newborn, and failure to treat appropriately severe hyperbilirubinemia without taking into consideration the child’s age in hours after birth. In many health care institutions, nurses have been given the prerogative of doing transcutaneous bilirubin testing, as well as ordering serum bilirubin, with a physician bearing the responsibility for a systems failure.

Prevention of hyperbilirubinemia is the best way to minimize the incidence of kernicterus. However, because some babies develop kernicterus with relatively modest bilirubin levels, no known absolute level of bilirubin below which the infant is completely safe is recognized. Also, other factors contribute to the ability of bilirubin to cross the blood-brain barrier. So today, notwithstanding the efforts of some hospital systems and the American Academy of Pediatrics to standardize this aspect of newborn care, approaches to the surveillance and management of hyperbilirubinemia remain individualized, both throughout the United States and the world.

Safe management of neonatal jaundice can be attained by adhering to the proposed management of neonatal jaundice provided in the American Academy of Pediatrics

Guidelines as the main tool used to avoid the risk of damage. Total serum bilirubin or transcutaneous bilirubin is to be performed on every neonate either at the recognition of clinical jaundice or before discharge regardless of whether jaundice was observed. For non-jaundiced neonates, the nursery staff is encouraged to

obtain the screening total serum bilirubin at the same time they obtained the state-mandated newborn screen for inborn errors of metabolism. Bilirubin values are plotted on an hour-specific nomogram and the corresponding percentile used to guide evaluation, therapy, and follow-up. Any newborn with bilirubin values in the High Risk or Intermediate High-Risk Zones requires a repeat total serum bilirubin value within 8-12 hours.

It also should be clear that there are fundamental behaviors needed to avoid the risk of hyperbilirubinemia. The purpose should not be to blame but to establish a safety culture. Performance of root-cause studies leading to the implementation of changes or reinforcing safe and effective behavior should be undertaken in the future. Defined behaviors should be driven by considerations that are not financial. Instead, they should be focused on commitment and should be universal, despite the cost pressures, liability constraints, and resistance to change. We must also respond adequately to the concerns of parents regarding the evolution of neonatal jaundice, poor feeding, breastfeeding difficulties, or changes in behavior or activities of the newborn, and failure to treat appropriately severe hyperbilirubinemia without taking into consideration the child’s age in hours after birth.

Complications

Consequences of inadequate surveillance and health-care assessments continue to present challenges to clinicians and families as well as state and local health departments, years after the occurrence of an extreme hyperbilirubinemia event. As a result of the bilirubin-induced toxicity, patients show a chronic disabling condition, characterized by choreoathetosis cerebral palsy, central neural hearing loss, palsy of the vertical gaze, and tooth enamel hypoplasia. Inappropriate and delayed use of healthcare resources to identify and manage infants at risk has led some families to resort to the medico-legal system to seek relief for their health-care burden. The medico-legal response of kernicterus provides the family limited and often inadequate compensation for their overall life-long health-care burden.

Patient Education

Parents should be informed of the importance of keeping follow up appointments, as well as they should be familiarized with the symptoms of poor feeding in breastfed babies and how to seek help.