Seizure-Related Deterioration in Treated Glioma: A Narrative Review of Nonconvulsive Status Epilepticus, Peri-Ictal Pseudoprogression, Treatment-Related Change, and True Progression

Background/Objectives: In glioma patients, acute neurologic deterioration may reflect nonconvulsive status epilepticus (NCSE), peri-ictal pseudoprogression, treatment-related change, or true progression. As these entities share imaging features, misdiagnosis can delay therapy. This review synthesizes evidence relevant to a proposed electroclinical-imaging framework for distinguishing seizure-related deterioration from treatment-related change and true progression. Methods: This narrative review synthesized English-language literature on tumor-related epilepsy, NCSE, peri-ictal imaging abnormalities, pseudoprogression, radiation necrosis, Response Assessment in Neuro-Oncology (RANO) criteria, and advanced imaging in adult diffuse glioma. Results: Seizure recurrence after glioma treatment may indicate tumor activity, but it may also reflect radiation injury, postoperative gliosis, edema, metabolic disturbance, medication effects, or transient peri-ictal change. NCSE is particularly important because it may present with aphasia, confusion, impaired consciousness, behavioral change, or deficits without convulsions, making electroencephalography central for unexplained deterioration. Seizure activity can also produce transient magnetic resonance imaging (MRI) or positron emission tomography (PET) abnormalities, including enhancement, fluid-attenuated inversion recovery (FLAIR) hyperintensity, diffusion restriction, and perfusion changes that mimic recurrence. Conclusions: This review proposes a structured electroclinical-imaging framework incorporating early EEG, seizure history, treatment timing, corticosteroid and antiseizure response, multimodal imaging, and longitudinal reassessment for prospective evaluation in treated glioma patients with new neurologic decline.