An autopsy study of a patient with refractory status epilepticus: MRI findings and histopathological correlation

Abstract

Abstract Background Status epilepticus (SE) has been defined as a seizure that persists for more than 5 min. If SE persists despite benzodiazepine and appropriately dosed antiseizure medications, it could be regarded as refractory SE (RSE). New-onset refractory status epilepticus (NORSE) is a separate syndrome that occurs in individuals without active epilepsy or other preexisting relevant neurological disorders. A small number of neuropathology reports of patients who died of SE, RSE and NORSE are available, revealing hypoxic and ischemic neuronal damage and cortical laminar necrosis (CLN). CLN is a well-known sequela of SE, which has been often suspected radiologically, although its anatomical background is largely unknown. Case presentation An 84-year-old man with a history of malignant lymphoma in complete remission presented with high fever and impaired consciousness. He developed tonic-clonic convulsions, which lapsed into SE. CSF revealed a normal cell count and elevated protein. MRI of the brain showed high signal intensities on diffusion-weighted and FLAIR images in the mid-temporal lobe bilaterally and left insular cortex. EEG showed epileptic discharges on the left side with an extreme delta brush pattern. He was diagnosed with possible autoimmune encephalitis. Despite treatments, he remained comatose and died of pneumonia, 24 days after the onset of seizures. A complete autopsy failed to reveal the presence of malignancy. Neuropathologically, the brain showed atrophic changes involving the insular cortex, orbitofrontal cortex and medial temporal lobe, predominantly on the left side. Histologically, the lesions corresponding to the abnormal MRI images revealed CLN involving the mid- cortical layers. Remarkably, this was associated with perivascular and intraparenchymal infiltration of plasma cells and T lymphocytes, which was also seen in the overlying subarachnoid membrane and in the adjacent intact appearing parenchyma. Conclusion The present case demonstrates that RSE with cortical involvement on MRI could be anatomically associated with CLN, which is accompanied by massive infiltration of plasma cells and T lymphocytes. The novel association of CLN and lympho-plasmacytic infiltration requires further investigation.