Epilepsia partialis continua may be a rare electroclinical feature of anti-Hu encephalitis: a pediatric case report

Background: Paraneoplastic neurologic syndromes with anti-Hu antibodies refer to a spectrum of neurologic disorders. Rare cases of extra-limbic encephalitis presenting with seizures have also been reported. However, these seizures rarely manifest as epilepsia partialis continua (EPC). We report an anti-Hu encephalitis pediatric case with EPC. Case description: A 3-year-and-4-month-old male presented with EPC after neuroblastoma resection for 6 months. Neuronal antibody testing revealed highly positive anti-Hu antibody in both serum and cerebrospinal fluid. Anti-Hu encephalitis with EPC was diagnosed. Initial immunotherapy including intravenous immunoglobulin and methylprednisolone had a transient effect, and the symptom recurred 1 month later. The EPC still existed even with the treatment of prednisone, mycophenolate mofetil, oxcarbazepine, valproic acid, and clonazepam. Conclusion: EPC may be a rare but underrecognized electroclinical feature of anti-Hu encephalitis. It is important to consider anti-Hu encephalitis in patients presenting with new-onset EPC. The heterogeneity in clinical symptoms, EEG and imaging manifestations may indicate the existence of complex and diverse mechanisms. The prognosis of this disease is speculated to be poor. Antiseizure medications and surgery often fail to control the progression of the disease. Immunotherapy may benefit some patients.