Scar Epilepsy: When Old Brain Injuries Cause Seizures Years Later

Scar epilepsy — technically called lesional or structural epilepsy — occurs when a damaged area of the brain (a "scar" or lesion) becomes an abnormal electrical focus that generates seizures. The original brain injury may have occurred years or even decades before the first seizure. In India, the most common causes of scar epilepsy are distinct from those in Western countries, owing to the high prevalence of certain brain infections.

Common Causes in India

Neurocysticercosis (NCC): By far the most common cause of new-onset epilepsy in adults in India — accounting for up to 50% of cases in some series. The tapeworm Taenia solium forms cysts in the brain; when the cyst dies, it calcifies, leaving a calcified scar that can generate seizures for years. The calcified granuloma is visible on CT scan.

Hippocampal sclerosis: Scarring of the hippocampus (memory area of the temporal lobe) — often the long-term consequence of a prolonged febrile seizure in childhood (febrile status epilepticus). Causes refractory temporal lobe epilepsy in adults. The characteristic seizure: focal unaware seizures with epigastric aura and automatisms. MRI shows a shrunken, bright hippocampus on FLAIR sequences.

Post-stroke epilepsy: 2–4% of ischemic stroke survivors develop epilepsy. The infarcted tissue and surrounding gliotic scar is epileptogenic. Early post-stroke seizures (within 7 days) do not indicate epilepsy; late seizures (after 7 days) are more likely to recur.

Traumatic brain injury: Cortical contusion with glial scarring — particularly after penetrating head injuries. Risk of post-traumatic epilepsy increases with injury severity.

Treatment

Anti-seizure medications (ASMs) are the first line — selected based on seizure type and MRI findings. For hippocampal sclerosis that is drug-resistant, surgical resection of the sclerotic hippocampus achieves seizure freedom in 60–80% of carefully selected patients. This is one of the most effective surgical procedures in all of medicine. MRI brain and EEG evaluation for unexplained seizures: Sri Anand CNC, Chanda Nagar, Hyderabad. Call +91 90633 66983.