Status Epilepticus

Overview

What is status epilepticus?

  • There are different forms of Status Epilepticus, defined by the seizure type, e.g. convulsive, absence, tonic, myoclonic.
  • Convulsive Status Epilepticus (CSE) is defined as a tonic-clonic seizure that lasts for 30 minutes or longer, or recurrent seizures without regainging consciousness in between and lasting greater than 30 minutes.1
  • Seizures that persist beyond five minutes frequently evolve to status epilepticus. Acute seizure management is therefore implemented at 5 minutes. This is the operational definition of status.
  • CSE has a mortality rate in children of approximately four per cent. Neurological sequelae of CSE (epilepsy, motor deficits, learning difficulties, and behaviour problems) are age dependent, occurring in six per cent of those over the age of three years but in 29 percent of those under one year.

Causes

  • It is important to look for a cause, as CSE can be a complication of acute illness such as encephalitis, meningitis, metabolic problems (e.g. hypoglycaemia), or can occur as a manifestation of epilepsy.
  • The highest incidence is in the first year of life. Prolonged Febrile Seizure is the most common cause of Status Epilepticus.1
  • 1. Singh R. K., Stephens S., Berl M. M., Chang T., Brown K., Vezina L. G., Gaillard W. D. Prospective study of new-onset seizures presenting as status epilepticus in childhood. Neurology. 2010;74:636–642

Management

Clinical Practice Guidelines for Management of Status Epilepticus

NSW Clinical Practice Guidelines, Infants and children: Acute Management of Seizures1 (algorithm pg 4).

  • The first step in the management of the patient who is having a seizure is to assess and support airway, breathing and circulation.
  • The timing in the protocol is from onset of seizure, and not from the arrival to the Emergency Department .
  • Given that most acute seizures in children stop spontaneously, usually during transit to hospital, it should be assumed that if a child is still convulsing on arrival in the Emergency Department, the seizure will continue unless treated. In this situation the child should be treated as if they were in ‘established’ status epilepticus.
  • After no response to two doses of midazolam, appropriate second line antiepileptics should be administered. Refer to the  timeline to the left of the diagram in the algorithm (page 4 of above link) and note in particular, that a long acting anticonvulsant (e.g. Phenytoin) should be introduced early (i.e. at 15 minutes).
  • Prolonged seizures and/or repeated doses of anti-epileptic medications may lead to compromise of breathing requiring ongoing support including intubation. In assessing medication load, factor in dosages of benzodiazepines given by carers and ambulance personnel. 

If a patient is already on levetiracetam, the intravenous preparation may be given at the same dosage as that given orally and consideration given to an additional load of levetiracetam.

In 2019 three papers were published related to second line treatment of convulsive status. In the studies EcLIPSE2and ConSEPT3, both randomised controlled trials, phenytoin and levetiracetam were compared. The primary outcome measures were not different for either drug. Adverse effects were not significantly different.

The ESETT4 study was a randomised trial of three anticonvulsants: levetiracetam, valproate and fosphenytoin in children and adults.  Each drug led to seizure cessation and improved alertness by 60 minutes in approximately half the patients. The three drugs were associated with similar incidences of adverse effects.

 

Refractory Status Epilepticus:

  • Defined as a failure of response to two AEDs, including first line therapy.
  • Other drugs used in this situation include: midazolam, propofol, barbituates.
  • 1. NSW Clinical Practice Guidelines, Infants and children: Acute Management of Seizures
  • 2. Lancet vol 393 (10186) 2125-2134, 2019
  • 3. Lancet vol 393 (10186), 2135-2145, 2019
  • 4. New England Journal of Medicine: 381;22,2103-2113;2019

Resources