Acute Autoimmune Limbic Encephalitis Associated with GABABR Antibody in a Patient with Advanced Squamous Cell Carcinoma of the Cervix Treated with Pembrolizumab: A Case Report
Shiv Jha1, Lauren Gluck2, Hamza Khan-Tareen2
1Neurology, Montefiore Medical Center/ Albert Einstein College of Medicine, 2Montefiore Medical Center
Background:
A 63-year-old woman with recurrent history of cervical cancer with hepatic metastasis treated with multiple cycles of chemotherapy was started on immunotherapy with pembrolizumab, developed new-onset seizures, memory loss, and encephalopathy, developed refractory status epilepticus, found to have a positive GABABR antibody in serum and features suggestive of autoimmune limbic encephalitis, was treated with IV methylprednisolone with minimal improvement followed by 5 days of IVIG therapy. The patient responded well, her consciousness improved, and was able to be extubated eventually.
Results:
The patient's MRI brain with contrast revealed non-enhancing signal hyperintensity and swelling in the right hippocampus, indicative of limbic encephalitis. The serum autoimmune encephalopathy panel confirmed the presence of GABABR antibodies, while the routine CSF analysis and paraneoplastic panel were unremarkable. Continuous EEG showed electrographic seizures originating from the left temporal region initially, followed by burst suppression, and later lateralized quasi-periodic discharges from right fronto-central region with moderate background encephalopathy.
Conclusions:
Our case demonstrated the rare occurrence of autoimmune limbic encephalitis in case of cervical squamous cancer with GABABR, neuronal surface receptor, antibody-mediated CNS inflammation presenting with seizures, encephalopathy status post immunotherapy with pembrolizumab, an immune checkpoint inhibitor.
Anti-GABABR antibody mediated limbic encephalitis is uncommon but potentially treatable condition and should be in differential diagnosis of patients presenting with new-onset seizures, refractory seizures, memory loss, and altered mental status in context of cancer or should be evaluated thoroughly for underlying cancer if presented with limbic encephalitis; early diagnosis and prompt treatment are vital for better outcomes.