Use of Intravenous Immunoglobulins in Pediatric Viral Meningoencephalitis: A Real-World Retrospective Observational Study.

Background: Viral meningoencephalitis is a frequent cause of acute central nervous system infection in children, particularly in neonates and young infants. Although etiological diagnosis has improved through molecular testing, management remains largely supportive, and intravenous immunoglobulins (IVIGs) are occasionally used in clinical practice despite limited supporting evidence. Methods: We performed a single-center retrospective observational study including pediatric patients aged 0-10 years admitted between 2016 and 2025 with molecularly confirmed viral meningoencephalitis. Demographic, clinical, microbiological, therapeutic, and follow-up data were collected. Neurological outcomes and length of hospital stay were compared between patients treated with IVIG and those who were not. Results: Twenty-nine patients were included. Enterovirus was the most frequently identified pathogen (50.0%), followed by human herpesvirus (35.7%) and human parechovirus (14.3%). IVIG was administered to 28% of patients, all with enterovirus infection. IVIG-treated patients were significantly younger at presentation and more frequently presented with apnea (42.9% vs. 0%, p = 0.014). Most patients had a favorable neurological outcome (85.7%). Unfavorable outcomes, including neurodevelopmental delay and/or epilepsy, occurred in a minority of cases (14.3%) and exclusively in enterovirus-infected patients. No significant association was found between IVIG administration and neurological outcome. Conclusions: In this real-world pediatric cohort, IVIG use was associated with more severe clinical features rather than improved neurological outcomes, underscoring the need for careful consideration and further investigation in this setting, particularly in the subgroup of infants with enterovirus encephalitis.