The Clinical Response of California Serogroup Virus Neuroinvasive Disease in a Pediatric Patient to Intravenous Immunoglobulin (IVIG) Therapy

Objective NA. Background California serogroup (CSG) viruses are commonly associated with neurologic disease. There are few cases of CSG viruses where IVIG has been proven to help. We report a young child with neuroinvasive CSG virus encephalitis treated with IVIG and associated outcome. Design/Methods A retrospective chart review. Results A 6 year old boy, previously healthy presented with fluctuating mental status with vomiting, fatigue, and fever starting six days prior to presentation. He began to have repetitive movements of rubbing his nose, and twisting movements of the upper extremities with mild eye deviation to the left with no EEG correlate. He required PICU admission for desaturations and altered mental status requiring intubation with sedation. He was found to have positive serum IgG and IgM antibody titers 1:128 of CSG viruses. IgG and IgM antibody titers of CSG viruses was negative (<1:1) in CSF. Of note he was positive for human metapneumovirus IgM antibodies. His serum and CSF NMDA was negative suggesting California encephalitis is not likely associated with NMDA encephalitis. His MRI brain resulted with extensive diffusion restriction throughout the frontal, parietal, and temporal cortex as well as non-diffusion restricting signal abnormality involving the basal ganglia and brainstem, suggesting a para-infectious encephalitis. He received IVIG given his worsening mental status starting on day 14 of admission. Neurological symptoms gradually improved after IVIG treatment. Despite therapies he displayed difficulties with focus and attention. 6 months after initial presentation his routine EEG showed frequent, sleep activated, 1-3 seconds bursts of irregular generalized spikes-and-slow wave complexes. Patient was continued on levetiracetam with no seizures. Conclusions This report highlights a severe case of encephalitis with CSG viruses. Although it is not clear whether time or IVIG helped in this patient case, it seemed to have shortened his acute altered mental status although he still has long-term learning difficulties.