347. Etiologies in a Cohort of Pediatric Patients Who Underwent CSF Metagenomic Next Generation Sequencing

Abstract

BackgroundThe differential diagnosis in pediatric patients presenting with concern for CNS infections and/or autoimmune disorders is broad. Despite recent advances in diagnostic modalities, many cases may remain undiagnosed. For example, approximately 50% of pediatric patients with encephalitis do not have an identified etiology. Use of metagenomic next-generation sequencing (mNGS) may improve the diagnostic yield. This study evaluated etiologies in a cohort of pediatric patients who underwent CSF mNGS.MethodsRetrospective cohort study of all hospitalized patients < 21-years-old who underwent CSF mNGS at a tertiary pediatric hospital from June, 2017 - February, 2020. Final diagnosis was assigned by two independent study physician reviewers (pediatric infectious disease and neurologist) based on documentation including discharge summaries, consult notes, and subsequent clinic notes where available.ResultsThirty-seven patients (59% female, median age 9 (1–17) years) were identified (21 with encephalitis). Twenty-six (70%) had a definite diagnosis – 10 (27%) infectious, 11 (30%) autoimmune, 5 (14%) other. The most common etiology was anti-MOG antibody associated meningoencephalitis (n=4, 11%). Among infections, Powassan virus encephalitis (n=3, 8%) was most common; other infectious etiologies included EBV, neuroborreliosis, rubella, and Eastern Equine encephalitis. Eight (22%) had a positive result on CSF mNGS; 7 were clinically significant including change in management in 5 of 8 (63%) patients.ConclusionIn this cohort of pediatric patients who underwent CSF mNGS, an etiology was identified in 70%. Eight patients had a positive result on mNGS which resulted in change in management for the majority of patients. These data suggest that CSF mNGS is high-yield and impacts clinical care. However, given the significant cost of mNGS, future directions include cost analyses to determine when and in whom CSF mNGS should be sent.DisclosuresAsim A. Ahmed, MD, Karius (Employee)