Histopathological evidence that hippocampal atrophy following status epilepticus is a result of neuronal necrosis

Abstract

Medial temporal lobe epilepsy is commonly associated with hippocampal atrophy on MRI and hippocampal sclerosis on histopathological examination of surgically-resected specimens. Likewise, it is well-established that prolonged seizures and status epilepticus can lead to hippocampal edema as noted on MRI. In this paper, the authors present an unusual patient with prolonged refractory status epilepticus, due to limbic encephalitis associated with anti-GAD antibody, who underwent palliative epilepsy surgery. Bilateral hippocampal edema was noted on preoperative MRI. Histologic evaluation confirmed presence of acute necrosis and neuronal loss in the left hippocampal formation. Follow-up MRI several months after surgery demonstrated severe atrophy of the contralateral right hippocampus. This is the first clear histopathological evidence that hippocampal atrophy following status epilepticus is the result of acute neuronal necrosis and cell loss.

Keywords: Anti-GAD antibody; Atrophy; Autoimmune encephalitis; Hippocampal necrosis; Hippocampal sclerosis; Limbic encephalitis; Refractory status epilepticus; Seizures.