Late-Onset Temporal Lobe Epilepsy Following Subarachnoid Haemorrhage: An Interplay Between Pre-existing Cortical Development Abnormality and Tissue Damage

Epilepsy occurring after intracranial hemorrhage is commonly attributed to acquired cortical injury, including ischemia, hemorrhagic transformation, and hemosiderin deposition. Parenchymal hemosiderosis is a recognized epileptogenic factor, while temporal lobe epilepsy may also arise from hippocampal sclerosis, malformations of cortical development, or low-grade tumors. In clinical practice, seizures are often presumed to result solely from the preceding brain insult based on neuroimaging findings. However, coexisting and previously undiagnosed epileptogenic lesions may influence seizure onset and treatment response. This sample case report presents a patient with medically refractory epilepsy following aneurysmal subarachnoid hemorrhage, in whom surgical management revealed an underlying focal cortical dysplasia type 1a, highlighting a multifactorial mechanism of epileptogenesis.