Clinical significance and outcome of subclinical status epilepticus in adults

Abstract

We reviewed the medical records and the EEGs of all adults treated for status epilepticus (SE) in our center in 4 years. EEG detected subclinical SE in almost half (49%) of the 45 consecutive patients identified. Comparing patients with and those without subclinical SE, we noted that patients with subclinical SE were older ( p = 0.02) and more likely to have focal brain lesions ( p = 0.04). In the absence of focal brain lesions, subclinical SE was still more common in old adults ( p < 0.01). Regardless of age, subclinical SE was more difficult to control than clinically overt SE ( p = 0.001). Although 24% of all patients died in ⩽60 days, late mortality was not associated with subclinical SE ( p > 0.05). However, an association between late mortality and presence of focal brain lesions was suggested by a low p-value (0.053). Subclinical SE appeared on the EEG as frequent discrete seizure episodes in all but 3 patients. None of the patients had a progressive sequence of EEG patterns, as was reported in the literature. Initiation of treatment before EEG recording in most of our patients (82%) might have interrupted the sequential appearance of the EEG patterns.