320 - Relationship of Severity of Neonatal Encephalopathy to the Severity of Brain Injury

Publication Number: 320.6176

Sameeia Iqbal, CHOC Children's Hospital of Orange County, Anaheim, CA, United States; Brenda Rieger, CHOC Children's Hospital of Orange County, Orange, CA, United States; Justin Shen, CHOC Children's Hospital of Orange County, Orange, CA, United States; Tricia Morphew, CHOC Children's Hospital of Orange County, Bothell, WA, United States; Terrie Inder, Childrens Hospital of Orange County, Orange, CA, United States

Background: Neonatal encephalopathy (NE) is a disease that causes neuronal and white matter injury. Therapeutic hypothermia (TH) is proven to reduce risk of death and neurodevelopmental impairment in infants with moderate to severe NE. Increasingly, infants with milder severity of NE are receiving TH. The relationship of the extent of NE, including infants with mild disease, to the extent of brain injury documented on magnetic resonance imaging (MRI) has been studied limitedly.

Objective: Investigate the distribution of MRI severity corresponding to the degree of NE (mild, moderate, and severe) in a longitudinal cohort of patients at the Children’s Hospital of Orange County (CHOC) and perform a comparison with data from a repository of infants at Brigham and Women’s Hospital (BWH).

Design/Methods: Data collection occurred from 1/23-10/24, focusing on infants who received TH at CHOC. We gathered information on maternal and delivery histories, blood gas values, and MRI results. Two independent readers graded MRIs using the Weeke scoring system (Weeke et al J Pediatr. 2018). We compared MRI severity scores for infants with NE receiving TH against their impairment classifications based on either the neonatal encephalopathy score (Thiim et al. J Pediatr. 2023) or Sarnat score. This CHOC repository was then compared with previous findings from BWH (Szakmar, 2021).

Results: Cohorts 1 and 2 had similar demographics (Table 1). When comparing severity of HIE/NE, cohort 1 had more cases of moderate and severe encephalopathy, with cohort 2 having more mild cases. Figure 1 reveals the relationship between NE severity in relation to MRI findings based on the MRI Weeke score in cohort 1. Range of total MRI Weeke scores for 126 patients was a median score of 1.0 (IQR: 0.0, 4.0). Mild to moderate NE cases had a similar distribution of MRI Weeke scores, with most cases of scoring less than 3. Importantly, 10 moderate (13%) and 4 mild (17%) scored with significant abnormalities on MRI despite TH. Severe NE was associated with higher MRI Weeke scores when compared to the mild and moderate cases (p-value = 0.004).

Conclusion(s): Our cohort reports similar findings to those published in a comparable cohort of infants with NE. In our cohort, infants with mild or moderate NE appear to have similar MRI Weeke scores, generally in the low - normal range, although 15-20% are significant. Whereas severe NE is strongly associated with higher MRI Weeke scores. These findings support the premise that a) mild and moderate encephalopathy have similar risk of abnormal MRI outcomes; and b) severe encephalopathy may not benefit to the same extent from TH.

Table 1
Table 1.pdfDemographic, prenatal, and clinical description of cohorts 1 and 2

Figure 1
Figure 1.pdfTotal MRI Weeke Score overall and by HIE/NE

Table 1
Table 1.pdfDemographic, prenatal, and clinical description of cohorts 1 and 2

Figure 1
Figure 1.pdfTotal MRI Weeke Score overall and by HIE/NE