Early diagnosis of nonconvulsive status epilepticus due to lithium intoxication using 6-channel electroencephalography.

Abstract

Nonconvulsive status epilepticus is a severe complication of lithium intoxication that requires prompt diagnosis and treatment. While conventional electroencephalography (EEG) remains the gold standard for diagnosis for nonconvulsive status epilepticus, its implementation in emergency settings can be challenging and time-consuming. We present a case in which simplified EEG with six electrodes enabled rapid detection and monitoring of nonconvulsive status epilepticus in lithium intoxication in the emergency setting. A 65-year-old woman with stable bipolar disorder presented to our emergency department with impaired consciousness. She had been maintained on lithium carbonate (1600mg daily) and carbamazepine (400mg daily) for over 10 years. Following two weeks of nausea and recent onset of agitation and slurred speech, she developed generalized convulsions. Laboratory examinations revealed elevated serum lithium (3.88 mEq/L) and acute renal dysfunction (creatinine 347.5μmol/L). After resolving initial convulsions, a simplified sixelectrode EEG (Neurofax EEG-1250, Nihon Kohden Corporation, Tokyo, Japan), applied by an emergency physician, demonstrated generalized spike and wave patterns consistent with nonconvulsive status epilepticus. Despite initial seizure control with midazolam during intubation, continuous EEG monitoring revealed recurrent nonconvulsive status epilepticus. After hemodialysis and continued deep sedation, she was discharged on day 40 without neurological sequelae. This case demonstrates the utility of simplified EEG in emergency settings for early detection and monitoring of nonconvulsive status epilepticus in lithium intoxication. The ability of emergency physicians to apply and interpret simplified EEG enabled timely intervention and prevention of neurological complications. While further research is needed to validate interpretation protocols by non-EEG specialists, simplified EEG shows promise as an accessible tool for rapid assessment of neurotoxicity in lithium intoxication, potentially improving patient outcomes through earlier intervention.