545: OPTIC NERVE SHEATH DIAMETER AS A PREDICTOR OF BRAIN SWELLING IN PEDIATRIC CEREBRAL MALARIA

Abstract

Introduction: Cerebral malaria (CM) is an important cause of death in children in low-and-middle income countries (LMICs) with a case fatality rate of >15%. Brain swelling on magnetic resonance imaging (MRI) is associated with morbidity and mortality in CM; however, this modality is expensive and unavailable in many LMICs. Optic nerve sheath diameter (ONSD) measurement is an inexpensive, non-invasive method of detecting increased ICP in other neurocritical illnesses. We hypothesized that increased ONSD would correlate with brain swelling on MRI and would be higher in survivors with neurological sequelae and non-survivors. Methods: We performed a retrospective chart review of 207 children aged 0-12 years in Blantyre, Malawi from 2013-22 with CM as defined by the World Health Organization. Brain swelling on admission MRI was characterized by brain volume scores (BVS) assigned by two blinded pediatric neuroradiologists; severe swelling was defined as 7-8, mild-to-moderate as 4-6, normal as 3. Admission ONSD measurement was taken via portable ultrasound (GE Logiq e); normal was defined as < 4.5 mm. Favorable outcome in survivors was defined as a grossly normal neurological exam on discharge. Data were compared using Kruskall-Wallis and Pearson’s correlation tests utilizing Stata (College Station, TX). Results: Median age of the cohort was 50 months (IQR 40); 49% (n=102) were female. 73% (n=152) had a favorable outcome, 12% (n=25) an unfavorable outcome, and 14% (n=30) died. Twenty-nine (14%) had a normal BVS, 134 (65%) had mild-to-moderate swelling, and 44 (21%) had severe swelling. ONSD was elevated in 86% (n=178) of patients overall; when compared by BVS group, it was elevated in 79% (n=23) of normal, 87% (n=117) of mild-to-moderate, and 86% (n=38) of severe. There was a weakly positive correlation between BVS and ONSD (r=0.14, p=0.05). Median ONSD was not significantly different when compared by discharge outcome (p=0.11) or when compared by BVS (p=0.18). Conclusions: ONSD was not a reliable tool to identify increased brain swelling as detected on MRI in children with CM. This may be due to heterogenous mechanisms leading to abnormal MRI findings. Future studies to identify an alternative method of early identification of children with CM that are high risk for morbidity and mortality are urgently needed.