Most seizures end after a few moments or a few minutes. If seizures are prolonged, or occur in a series, there is an increased risk of status epilepticus. The term literally means a continuous state of seizure.
Status epilepticus is usually defined as 30 minutes of uninterrupted seizure activity. However, the Epilepsy Foundation advises parents and the public to call for emergency assistance when a convulsion continues for more than 5 minutes without signs of stopping. The experts who comprise the Foundation’s Working Group on Status Epilepticus have recommended that emergency room physicians treat as status epilepticus if seizure activity has continued for more than 10 minutes.
Convulsive status epilepticus is a medical emergency. An estimated 42,000 deaths and thousands more instances of brain damage per year follow episodes of status. The majority of these episodes occur in people who do not have epilepsy but have other acute medical illnesses, such as brain tumors or infections, craniocerebral trauma, or cerebrovascular disease. Ingestion of cocaine or other illegal drugs, and toxic or metabolic disorders, can also trigger a status episode.
Death or brain damage from status seizures (as opposed to death from the underlying cause) is most likely to result from:
- Direct damage to the brain caused by the injury that causes the seizures
- Stress on the system from repeated generalized tonic clonic seizures
- Injury from repeated electrical discharge in the brain.
About 25 percent of status epilepticus cases occur in people who have been diagnosed with epilepsy. At some point in their lives, 15 percent of people with epilepsy will experience an episode of status epilepticus. The most common precipitating factor in these cases in adults is withdrawal from medication or noncompliance with the regimen. There may,however, be no obvious cause for the episode. Ten percent of people who later progress to epilepsy experience their first seizure as a status episode.
Status epilepticus is most common in the very young and the very old, with the lowest incidence at ages 15-40. In the very young, febrile seizures are a leading cause of status epilepticus. In middle-aged adults, single, unprovoked episodes of status are common; later in life, stroke is a common cause.
In all cases, prompt treatment is the key to preventing serious outcomes. The goal of treatment is to stop the seizure activity as quickly as possible and treat any underlying precipitant. Mortality in children and adults is minimized when status lasts less than one hour. After an hour it increases slightly in children but jumps dramatically to close to 38% in adults.
Any type of epileptic seizure can progress to status epilepticus, but convulsive status has the greatest potential for long-term damage. Nonconvulsive status includes continuous absence seizures and partial status epilepticus, including status involving simple partial seizures (called epilepsia partialis continua). Nonconvulsive status can present in various ways, including loss of speech, automatisms, and alteration of consciousness.
While not generally viewed as being as damaging as convulsive status, nonconvulsive status involves repeated excessive electrical discharges in the brain and should also receive prompt treatment.
Hospital treatment of convulsive status epilepticus generally includes use of such drugs as diazepam, lorazepam, phenytoin and phenobarbital, administered in a planned sequence.
Rectal diazepam gel (Diastat) may be prescribed for at-home or non-hospital use to stop bouts of prolonged seizures or clusters of acute repetitive seizures in people with a history of this type of seizure.