Nonconvulsive status epilepticus in a neurological intensive care unit: profile in a developing country

Nonconvulsive status epilepticus (NCSE) is an under-recognized cause of altered mental status. There are hardly any reported data on NCSE in developing countries.

Prospectively 210 consecutive patients with altered mental status admitted to neurological intensive care unit (NICU) of a tertiary care center in south India were studied for the frequency of NCSE. All patients were evaluated initially with 60-min emergent EEG (EmEEG) and subsequently by continuous EEG (cEEG) monitoring.

Of the 210 with altered mental status admitted to NICU, the diagnosis of NCSE was established in 22 (10.5%) patients, in 12 (55%) patients with 60-min EmEEG and in 10 (45%) after cEEG monitoring for 12 to 48 hours. Of the 22 patients with NCSE, 32% had subtle motor phenomena, these were not an initial presenting features, but were apparent during cEEG recording. Acute medical or neurologic etiology was the risk factor in 68% of patients. Central nervous system (CNS) infections and cortical sino-venous thrombosis (CSVT), respectively, accounted for 23% and 14% of the etiologies. Intravenous midazolam terminated NCSE in 19 patients and valproate in 2. Of the 15 patients with acute symptomatic NCSE, 4 (18%) had poor prognosis (3 deaths and one persistent vegetative state). The etiological risk factors in the 9 (41%) patients with excellent outcome included epilepsy (3), remote symptomatic (2), cryptogenic (1), and metabolic and drugs (3).

The frequency of NCSE in the current study was comparable with those in prior reports from developed countries. CNS infections accounted for about a fifth of the etiology. Outcome was excellent in patients with nonacute symptomatic NCSE. Initial 60-min EmEEG may be performed in establishing the diagnosis of NCSE, but almost half of patients with NCSE will be missed with this approach.