Post-IVIG Aseptic Meningitis in a Pediatric Patient With Kawasaki Disease: A Case Report.

Intravenous immunoglobulin (IVIG)-induced aseptic meningitis is a rare but well-recognized neurological complication that may closely mimic bacterial meningitis, making diagnosis challenging. Prompt recognition is essential to avoid unnecessary antimicrobial therapy and prolonged hospitalization. We report the case of a previously healthy 12-year-old boy who developed aseptic meningitis seven days after receiving high-dose IVIG for Kawasaki disease (KD). He presented with severe headache, vomiting, fever, and mild neck stiffness. Cerebrospinal fluid (CSF) analysis demonstrated neutrophilic pleocytosis (248 cells/mm³, 80% neutrophils) with negative Gram stain and bacterial cultures. Following the exclusion of infectious causes, the patient recovered completely with supportive care alone. This case highlights that IVIG-induced aseptic meningitis may occur later than the commonly reported 24-72 hours after infusion. Awareness of this uncommon but benign adverse event, together with careful interpretation of CSF findings and exclusion of infectious meningitis, is essential to ensure appropriate management, avoid unnecessary investigations and antibiotic therapy, and reassure clinicians and families regarding its excellent prognosis.