Rationale: Anti-gamma-aminobutyric-acid B receptor (anti-GABAB R) encephalitis is clinically characterized by seizures, cognitive disorders, and behavioral changes. Most patients are diagnosed with small-cell lung carcinoma.
Patient concerns: The patient suffered from a repeated grand mal seizure lasting for 10 minutes, intermittent speech vagueness, manic at night, and mental disorder.
Diagnosis: The patient was diagnosed with autoimmune encephalitis. The gamma-aminobutyric-acid B(GABAB) receptor antibody test result was positive. After a bronchoscopic biopsy, the patient was diagnosed with small-cell lung carcinoma.
Interventions: The patient was administered with intravenous immunoglobulin and Methylprednisolone. Etoposide was used after the small-cell lung carcinoma was diagnosed.
Outcomes: After immunotherapy, following the 4 months of Etoposide and antiseizure treatment, the neurology examination revealed a remarkable improvement. MRS score reduced from 5 to 1. Electroencephalogram (EEG) recovered to normal from an extreme delta brush (EDB) electroencephalographic-pattern.
Conclusion: Immunotherapy and Etoposide can improve the outcome of severe anti-γ-aminobutyric acid B receptor encephalitis with small-cell lung carcinoma. After immunotherapy and antineoplastic therapy, Electroencephalogram (EEG) can be recovered to normal from an extreme delta brush.