Epilepsy

Continue antiepileptics - Give antiepileptic drugs on schedule, including the morning of surgery, and resume them promptly afterward; a missed dose is a leading trigger. Plan an IV route if the patient can't take orals.

Drug choice - Favor agents that don't lower the seizure threshold; propofol and benzodiazepines are anticonvulsant. Methohexital, etomidate, and high-dose sevoflurane can provoke epileptiform activity — use them thoughtfully in poorly controlled patients.

Enzyme induction - Chronic antiepileptics induce hepatic enzymes and can cause resistance to non-depolarizing relaxants and opioids, so requirements may be higher; follow the twitch monitor.

Avoid triggers - Prevent hypoglycemia, hyponatremia, hypoxia, and marked hyperventilation, each of which can precipitate a seizure.

Manage an intraoperative seizure - Treat with a benzodiazepine or propofol, protect the airway and oxygenation, and look for a reversible cause.

Postoperative care - Watch for a postictal state and return to baseline mentation, and keep the antiepileptics uninterrupted.

Epilepsy is a chronic tendency to recurrent, unprovoked seizures — abnormal, hypersynchronous cortical neuronal discharges — ranging from focal to generalized tonic-clonic.

Most patients are maintained on antiepileptic drugs, and the dominant perioperative issue is not letting the perioperative period provoke a seizure: missed medication doses, sleep deprivation, metabolic derangement, and certain anesthetic agents all lower the threshold. Chronic antiepileptics also matter pharmacologically, since hepatic enzyme induction speeds the metabolism of many anesthetic drugs, and some agents are themselves pro- or anticonvulsant.