Absence status associated with focal activity and polydipsia-induced hyponatremia

We report a case of de novo absence status associated with focal discharge and polydipsia-induced hyponatremia. Nonconvulsive status epilepticus (NCSE) is classified as absence status or complex partial status. Absence status is characterized by bilateral synchronized spike and wave complex bursts and a variety of conscious disturbances. Possible precipitating factors for NCSE include benzodiazepine withdrawal, excessive use of psychotropic drugs, and electrolyte imbalances. Hyponatremia is a rare precipitating factor. In this case, the patient was 59 years old and had suffered from primary insomnia but had no history of epilepsy. NCSE improved by means of saline infusion. However after recovery from NCSE EEG revealed some spikes in the left frontal area. Absence seizures can also show generalized spike and slow waves, and cases of focal lesion-associated absence seizures have been reported. Although absence seizures and absence status are two distinct conditions, they should not be considered together. We assumed that hyponatremia induced by polydipsia precipitated epileptogenicity in the left frontal area, and then focal activity secondarily generalized and resulted in absence status.