Immune Checkpoint Inhibitor-induced Encephalitis: Pembrolizumab Triggering Seizures, Aphasia, and Personality Change
Stella Adetokunbo1, Juan Solano2, Gabrielle Pancio3, Saman Zafar4
1Einstein Health Network, 2Thomas Jefferson university hospital Einstein campus, 3Sidney Kimmel Medical College, 4Einstein Medical Center Philadelphia
Background:
The use of immune checkpoint inhibitors in cancer management is increasing, and new immune related complications are being recognized as our experience with this new treatment option grows. Rare neurological immune-related adverse effects are no longer rare and should be recognized early.
Design/Methods:
A 41-year-old female recently diagnosed with triple negative breast cancer on paclitaxel, carboplatin, and pembrolizumab presented with acute onset of confusion and expressive aphasia. A week earlier she was discharged on Keppra 500 mg BID for generalized tonic clonic seizure.
Her examination and vital signs were within normal limits except for stuttering speech and difficulty finding words. Her repetition and comprehension were intact. Labs were within normal limits with no leukocytosis and normal electrolytes.
She was admitted with broad differentials of autoimmune encephalitis vs pembrolizumab toxicity vs paraneoplastic syndrome. Her pembrolizumab and other immunologic agents were discontinued. MRI revealed no intracranial abnormality or pathologic enhancement. Lumbar puncture showed normal CSF cell count, culture with negative infectious and paraneoplastic panels.
Initial EEG reports left temporal polymorphic delta slowing with abundant left temporal sharp waves and she was started on 5 days intravenous Methylprednisolone at 1000 mg/day. She regained spontaneous speech with good eye contact. Repeat EEG showed no sharp waves, and she was discharged home on 80 mg/day Prednisone.
Results:
One week after discharge, she demonstrated hypomanic symptoms, and her prednisone was tapered to 40 mg/day. She made a slow but definite improvement in her mental status and mood.
Conclusions:
Neurological complications in patients with immune therapies have been thought to be rare but with increasing usage of these therapies, neurologists should be prepared to diagnose and treat these accompanying neurological complications. Future treatment guidelines to specify the duration of steroid treatment would be useful, as it can be difficult to determine complete recovery of psychiatric symptoms.
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