Seizure Causes: Etiologies Across the Lifespan

Seizure Etiology Framework (ILAE)

• Structural: Stroke, TBI, tumor, malformation (cortical dysplasia), hippocampal sclerosis, neurodegenerative.
• Genetic: Monogenic (SCN1A, KCNQ2), chromosomal, polygenic; developmental/epileptic encephalopathies.
• Infectious: Meningitis, encephalitis (HSV, autoimmune), neurocysticercosis, HIV, CMV, congenital.
• Metabolic: Hypoglycemia, hyponatremia, hypocalcemia, hypomagnesemia, hepatic/renal failure, mitochondrial disorders, inborn errors.
• Immune: Autoimmune encephalitis (anti-NMDA, LGI1, GABA_B), Rasmussen.
• Toxic/Withdrawal: Alcohol, benzodiazepines, stimulants, isoniazid, theophylline, antidepressants.
• Vascular: Stroke, AVM, cavernoma, vasculitis.
• Unknown (Idiopathic/Cryptogenic): No identifiable cause after workup (~30–40%).

Age-Specific Patterns

• Neonates: HIE, stroke, infection, metabolic, malformation.
• Infants/children: Febrile seizures, genetic epilepsies, cortical dysplasia.
• Adults: Stroke, tumor, TBI, alcohol, autoimmune, idiopathic.
• Elderly: Stroke, neurodegenerative, metabolic, tumor, polypharmacy.

Workup

History, neuro exam, EEG, MRI brain (epilepsy protocol), labs (glucose, electrolytes, renal/hepatic, toxicology, infectious/autoimmune panel as indicated), genetic testing.