Gregory Lawrence Holmes, M. D.
Clinical Neurophysiology Laboratory, Children's Hospital, Boston, Massachusetts, USA
Status epilepticus (SE) is a serious, life-threatening condition that requires prompt treatment. SE is one of the most frequent and serious neurologic emergencies encountered by pediatricians. SE is defined as more than 30 minutes of continuous epileptic seizure activity or two or more sequential seizures without full recovery of consciousness between seizures. In practical terms, a patient arriving at the emergency room seizing should be considered to be in SE. All of the seizure types can, under the correct circumstances, progress into status epilepticus. While SE can be classified as convulsive or non-convulsive, the convulsive type is the most common and serious. Refractory status epilepticus refers to cases that fail to respond to appropriate first-line drug treatment and persist for longer than 60 minutes.
Animal studies have demonstrated the importance of stopping SE quickly as there is evidence that the prognosis worsens with the continued duration of seizures. During prolonged tonic-clonic seizure activity, major metabolic disturbances occur, including hypoxia, hypotension, hypoglycemia, hyperkalemia, hyperpyrexia, and raised intracranial pressure. However, even when these systemic abnormalities are controlled the brain is at high risk for damage from excitotoxicity alone. There is considerable evidence that one of the causes of SE-induced brain injury is the toxic amount of glutamate that occurs during the seizure. Glutamate leads to excessive depolarization of neurons which results in intracellular increases of sodium and calcium. These intracellular ion changes lead to a cascade of changes ultimately resulting in cell death.
Proper management of status epilepticus therefore requires close attention to basic principles of life support. Systemic metabolic abnormalities must be recognized and treated. Once the patient is stabilized a search for etiologies should begin. While there is no "standard" form of treatment, it is imperative that the clinician use the correct dosage and have an understanding of the pharmacokinetics and side effects of each of the AEDs used.. Currently, four drugs are widely used initially in the treatment of status epilepticus: diazepam, lorazepam, phenytoin, and phenobarbital. All four drugs are highly efficacious.