Nonconvulsive status epilepticus in acute brain injury.

Whether or not nonconvulsive status epilepticus produces permanent brain damage is a source of controversy. Contributing to the controversy is the lack of clarity for classifying the clinical and electrographic phenomena that constitute nonconvulsive status epilepticus. Nonconvulsive status epilepticus commonly occurs in the context of an acute brain injury. For example, it commonly persists in generalized convulsive status epilepticus after convulsive activity has stopped, and it is not uncommonly associated with acute cerebral ischemia. Its clinical characteristics are ambiguous, subtle, and nonspecific making the diagnosis difficult. In the absence of EEG testing, it is likely to be missed or delayed. When acute brain injury and nonconvulsive status epilepticus occur concurrently, the severity of acute brain injury has traditionally been accepted as determining patient outcome. However, increasing evidence suggests that the two conditions are synergistically detrimental and increase brain injury. Guidelines remain to be established for the intensity and duration of anticonvulsant therapy in these patients. Evidence suggests that, in the absence of extreme and irreversible acute brain injury, early intensive intervention is necessary to improve the otherwise poor outcome of these patients.