Epilepsy and electroencephalography
Epilepsy and electroencephalography
The exam tests seizure classification, EEG pattern recognition, status epilepticus management, and antiseizure medication selection. Focal onset, generalized onset, and unknown onset are classified by semiology and EEG. Typical absence seizures show 3-Hz generalized spike-wave discharges and are aggravated by carbamazepine; juvenile myoclonic epilepsy often requires lifelong valproate avoidance in pregnancy. Convulsive status epilepticus is a medical emergency: benzodiazepine first, then an IV second-line agent, then anesthetic-level therapy with intubation for refractory cases. EEG also identifies nonconvulsive status, periodic discharges, and lateralized periodic discharges in acute brain injury.
Worked example
A 24-year-old has 20 minutes of generalized convulsions. Give a benzodiazepine promptly; if seizures continue, give levetiracetam, fosphenytoin, or valproate. If refractory, intubate and use a continuous anesthetic infusion with EEG monitoring. Reasoning: this is convulsive status epilepticus, and delays increase neuronal injury. Check glucose, sodium, and toxins while treating.
Traps
Do not give carbamazepine for absence or myoclonic seizures; do not miss nonconvulsive status in unexplained confusion; do not use valproate in a person who may become pregnant without weighing teratogenicity; remember phenytoin has zero-order kinetics and cardiac risks.