Evaluation and initial treatment of encephalopathy in newborns following acute perinatal event.
Review common mechanisms of injury; identify encephalopathy on physical examination; recommendations for initiation of hypothermia therapy; early management of the infant undergoing hypothermia.
Hypoxic ischemic encephalopathy (HIE) will occur in 1–6/1000 births, or approximately 9000–12,000 newborns in the United States each year. Given the high rate of mortality and morbidity attributed to the condition, it is imperative for pediatricians to have a high index of suspicion and feel comfortable examining a newborn soon after birth, especially in the setting of an acute perinatal event, concerning history or abnormal cord blood gases. The Sarnat physical examination is a reliable scoring system to differentiate mild, moderate, and severe encephalopathy. For patients with moderate or severe encephalopathy, whole-body cooling is now the standard of care in neonatal intensive care units to decrease brain metabolism and help prevent secondary neuronal injury. Neonatal cooling has been found to decrease the composite primary outcome of death or major neurodevelopmental disability at 18 months from 63% to 48%, and was statistically significant for newborns with both moderate and severe HIE. These patients often require sedation and continuous EEG monitoring, and may require further cardiovascular and respiratory support depending on the extent of their illness. All cooled patients should have MRI imaging following cooling to help physicians and family anticipate long-term prognosis. Further research continues on the potential neuroprotective effects of erythropoietin, melatonin, and xenon as well as the free radical scavenging abilities of N-acetylcysteine and allopurinol to determine if any of these agents may further decrease long-term disease burden in this population.
When evaluated and treated promptly, randomized trials show that neonatal cooling of infants with moderate or severe encephalopathy leads to improved morbidity and mortality in approximately 1/7 cooled infants. Although treatment will require care in a neonatal intensive care unit, initial evaluation and initiation of cooling can be considered in any facility with a physician comfortable in Sarnat examination scoring, and with minimal equipment investment.
Practice Option #1: Evaluation of Whether a Patient is Demonstrating Moderate or Severe Encephalopathy
A neonatal encephalopathy assessment tool allows a physician to systematically determine the severity of a patient’s encephalopathy, and should be printed or easily accessible in the electronic medical record for hourly scoring. The infant should be scored on level of consciousness (normal, hyperalert, lethargic, or coma), spontaneous activity (normal, decreased, or absent), muscle tone (normal, hypotonic, or flaccid), posture (normal, mild distal flexion, strong distal flexion, or decerebrate), primitive reflexes (suck and moro: normal, weak, or exaggerated, respectively, intermittently absent, or incomplete, absent), and autonomic function (pupils dilated, constricted or fixed and dilated, heart rate normal, ...