Epileptic Emergencies: Early Treatment Can Make a Difference

Early acute treatment of epileptic emergencies may help prevent brain damage. "Don't wait to get the patient to the emergency department [ED]. The longer one waits to treat, the higher the chance for morbidity and mortality," said John M. Pellock, MD, chair of the Division of Child Neurology, Virginia Commonwealth University in Richmond, at the June 2006 meeting of the American Epilepsy Society (AES).

Pellock advocated that physicians judiciously prescribe diazepam (rectal formulation) for patients at risk for prolonged seizures. He also added that emergency medical services (EMS) personnel generally are equipped to deliver intravenous diazepam to seizure patients en route to the ED but that an at-risk patient need not be left waiting for an EMS vehicle to be helped.

What constitutes a prolonged seizure? In his presentation at the AES meeting, Michael C. Smith, MD, director of the Rush Epilepsy Center and associate professor in the Department of Neurological Sciences at Rush University Medical Center, stressed that seizures lasting 5 minutes or more should be regarded as "impending status epilepticus" (SE). Patients experiencing such seizures should be immediately treated with diazepam. "This is where we can make a difference," said Smith, because "the patient is more responsive to intervention" than when classic SE (seizure persisting for at least 30 minutes) takes hold. "The longer the duration of seizure, the later the EEG stage, and the more subtle the motor manifestations, the harder SE is to stop," he said.

Smith cited a study by DeLorenzo and colleagues¹ in which 43% of seizures lasting 10 to 29 minutes stopped spontaneously without treatment. "This means that nearly 60% do not resolve without treatment, resulting in significant mortality," Smith pointed out. "Once a seizure persists for 5 minutes, you're getting into status. It should be considered a true emergency." Failure to promptly treat results in significant hippocampal damage, manifesting most prominently as memory impairment, he explained.

Smith showed data from a study of children illustrating that seizure can be aborted in the overwhelming majority (96%) of patients if rectal diazepam is administered within the first 15 minutes of seizure onset.² If diazepam is administered outside of the 15-minute window, response falls to 57%.

On average, patients treated within 30 minutes of seizure onset have an 80% response to diazepam, he added, citing data from Lowenstein and Alldredge.³ However, response to diazepam falls as time-to-intervention increases. Those treated up to 120 minutes after seizure onset have a 44% response rate, which falls to 37% for those treated in excess of 120 minutes.

Some clinicians have concerns about administering diazepam or lorazepam too hastily, fearing that such agents will induce hypotension, cardiac dysrhythmia, or respiratory complications. Smith cited a study by Alldredge and colleagues⁴ showing that the rate of respiratory and cardiovascular complications in untreated patients (22.5%) was, in fact, double that of patients treated with lorazepam (10.6%) or diazepam (10.3%) in an out-of-hospital, emergency-response setting.

Once SE has taken hold, administration of intravenous lorazepam or diazepam in the hospital may still be useful; however, as SE persists, other agents must be considered, such as phenytoin, phenobarbital, and finally midazolam. Smith said that hospitals can improve outcomes for patients by establishing time-sensitive treatment protocols for impending SE and SE. He also noted that once the clinical signs of SE have ceased, an EEG reading is necessary to evaluate treatment response because the EEG may still show ictal activity.