Epilepsy Starting in Adults: Why New-Onset Seizures After 25 Must Be Investigated

Epilepsy in children often has no identifiable structural cause — idiopathic genetic epilepsies are common. But epilepsy beginning in adulthood — particularly after age 25 — should always prompt a thorough search for an underlying cause. The older the patient at onset, the more likely a structural or metabolic cause will be found. A new seizure in an adult is not "just epilepsy" until investigation has excluded a treatable underlying condition.

Causes to Exclude in Adult-Onset Epilepsy

Brain tumour: Both primary brain tumours (glioma, meningioma) and brain metastases (from lung, breast, colon, kidney cancer) can present with seizures. A seizure is sometimes the first symptom. MRI with gadolinium is essential.

Stroke and cerebrovascular disease: Previous stroke or small vessel disease can create epileptogenic cortical scars. New seizures in a person with hypertension, diabetes, or known vascular disease strongly suggest this aetiology.

Neurocysticercosis: As described — calcified parasitic cysts in the brain. Very common in India. Often the only symptom is recurrent focal seizures. CT brain reveals calcified lesions.

Autoimmune encephalitis: Anti-NMDA receptor and other autoimmune encephalitides can present with new-onset seizures, particularly in young adults — sometimes with psychiatric features initially.

Metabolic causes: Hypoglycaemia, hyponatraemia, uraemia, hepatic encephalopathy — all cause provoked seizures. These are not epilepsy — treat the metabolic abnormality.

Alcohol-related seizures: Alcohol withdrawal seizures occur 6–48 hours after the last drink. Chronic alcohol use also increases seizure susceptibility through multiple mechanisms.

Investigation Protocol

All adults with first seizure: MRI brain with gadolinium (preferred over CT); EEG; blood tests including glucose, electrolytes, liver and kidney function, calcium; ECG (to exclude cardiac cause of LOC); autoimmune antibody panel if clinical features suggest autoimmune aetiology. Sri Anand CNC, Chanda Nagar, Hyderabad. Call +91 90633 66983.