A 12-year-old boy in April 2026 developed aseptic meningitis seven days after receiving high-dose intravenous immunoglobulin for Kawasaki disease. The case highlights an uncommon, delayed-onset neurological complication requiring careful cerebrospinal fluid analysis to distinguish it from bacterial meningitis and avoid unnecessary antibiotic therapy.
Case Presentation and Initial Kawasaki Disease Treatment
The patient, who had no significant past medical history and was the only child of second-degree consanguineous parents, was admitted to a pediatric department in April 2026 presenting with persistent high-grade fever lasting six days. His clinical presentation fulfilled the diagnostic criteria for Kawasaki disease, featuring bilateral non-purulent conjunctivitis, a diffuse maculopapular rash, and oropharyngeal changes. Kawasaki disease remains the leading cause of acquired heart disease in children in developed countries, according to medical literature.
Initial echocardiography revealed no coronary artery abnormalities. The patient received a single infusion of intravenous immunoglobulin at a dose of 2 g/kg administered over 10 hours. This was combined with aspirin at an anti-inflammatory dose of 50 mg/kg/day for five days, followed by antiplatelet-dose aspirin. Oral prednisone at 1 mg/kg/day was also administered as adjunctive corticosteroid therapy for five days in order to improve control of the systemic inflammatory response and lower the risk of disease-related consequences.
Inflammatory markers showed steady improvement during the initial six-day hospital stay. C-reactive protein decreased from 119 mg/L at admission to 85 mg/L on day 3 and 4, and dropped to 4.32 mg/L by discharge on day 6.
Delayed-Onset Neurological Readmission
Twenty-four hours after discharge—marking seven days since the intravenous immunoglobulin infusion—the patient was readmitted. He presented with severe diffuse headache, three episodes of vomiting, marked fatigue, and a fever of 38.3°C, alongside mild neck stiffness. This timeline surpasses the commonly reported 24 to 72 hours after infusion typically associated with neurological adverse events.
Cerebrospinal fluid analysis revealed neutrophilic pleocytosis with 248 cells/mm³, consisting of 80% neutrophils. Microbiological evaluations, including negative Gram stain and bacterial cultures, successfully excluded infectious causes.
Broader Context and Diagnostic Challenges
Intravenous immunoglobulin-induced aseptic meningitis is a rare but well-recognized neurological complication that may closely mimic bacterial meningitis, making diagnosis challenging. Clinicians emphasize that prompt recognition is essential to avoid unnecessary antimicrobial therapy and prolonged hospitalization. While the condition shares clinical signs such as severe headache, fever, vomiting, and neck stiffness with infectious meningitis, following the exclusion of infectious causes, the patient recovered completely with supportive care alone. Awareness of this uncommon but benign adverse event, together with careful interpretation of cerebrospinal fluid 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.
Nearly six decades after Dr. Tomisaku Kawasaki first described the condition, Kawasaki disease remains the leading cause of acquired heart disease in children worldwide, yet its etiology continues to elude definitive explanation. Substantial progress has been made in recent years across multiple fronts: advances in coronary imaging, including computed tomography coronary angiography, have improved detection of distal and complex coronary artery abnormalities beyond the reach of conventional echocardiography; genetic and epigenetic studies have identified susceptibility loci and methylation signatures that offer clues to disease pathogenesis; single-cell transcriptomic and proteomic approaches are beginning to unravel the immune dysregulation underlying acute disease and its complications; and long-term follow-up studies are clarifying the natural history of coronary and vascular outcomes, including in children who defervesce spontaneously. At the same time, the emergence of multisystem inflammatory syndrome in children (MIS-C) during the COVID-19 pandemic has renewed global interest in KD-like inflammatory phenotypes and their shared and distinct immunopathological mechanisms.
