OBJECTIVES: To investigate clinical characteristics and outcomes of 
nonconvulsive status epilepticus (NCSE) after convulsive status epilepticus 
(CSE) and determine risk factors for unfavorable outcomes.
METHODS: We reviewed consecutive patients with NCSE after CSE over eight years 
in the neurological intensive care unit. Clinical presentations and the Salzburg 
EEG criteria for NCSE were used to identify patients with NCSE after CSE. 
Demographics, clinical features, and anti-epileptic treatment responses were 
collected and analyzed. Modified Rankin Scale (mRS) was used to evaluate 
three-month outcomes. A multivariate logistic regression model was used to 
determine independent prognostic factors.
RESULTS: Among 145 consecutive patients with convulsive SE, 48 (33.1%) patents 
eventually evolved into NCSE. Two patients with cerebral anoxia were exclude. At 
three-month follow-up, 23 patients (50.0%) had mRS ≥ 3, and 16 (34.8%) died. 
Thirty-two patients (69.6%) were given continuous intravenous anesthetic drugs 
(CIVADs). Fourteen patients (30.4%) had CIVAD at the rate >50% proposed maximal 
dose (PMD). There was a single predictor factor found significant after 
multivariate logistic regression analysis: the recurrence of EEG seizures within 
two hours of initiation of CIVAD at a dose of greater than half the proposed 
maximal dose (OR, 9.63; 95%CI, 1.08-86.18; p = 0.043). The use of CIVAD, even 
with a high dose (>50% PMD), was not independently associated with unfavorable 
outcomes.
CONCLUSIONS: The recurrence of EEG seizures within two hours of initiation of 
CIVAD at a dose of greater than half the proposed maximal dose predicts 
unfavorable outcomes in NCSE after CSE. The refractoriness of the seizures might 
be a significantly greater risk for poor outcome in NCSE after CSE than 
treatment with CIVADs.