Status Epilepticus Management

Generalised convulsive (tonic-clonic) status epilepticus is defined as a generalised convulsion lasting 30 minutes or longer, or repeated tonic-clonic convulsions occurring over a 30 minutes period without recovery of consciousness between each convulsion.¹

Estimated incidence is between 10-60 cases per 100,000 person/years². The incidence is higher in poorer populations. It recurs in over 13% of patients³.

Risk factors

• History of epilepsy
• Age under 5 years or elderly
• Genetic predisposition
• Mental handicap
• Structural brain pathology

• Drug withdrawal
• Intercurrent illness
• Metabolic disturbance (e.g. hypoglycaemia)
• Stroke
• Alcohol intoxication or withdrawal

The diagnosis of tonic-clonic status is usually clear, although it needs to be distinguished from pseudo-status epilepticus; non epileptic attacks with a psychological basis. Non-convulsive status (e.g. absence status or continuous partial seizures with preservation of consciousness) may be more difficult. In non-comatose patients it may present as confusion, personality change or psychosis. Diagnosis depends on results of electroencephalography (EEG). Aetiology and conscious level predict outcome⁴.

• General protective measures:
  • Make the patient comfortable
  • Ensure the head is protected
  • Remove false teeth, taking care when fingers in the mouth
  • Release constricting neck wear
  • Move if in a dangerous situation (e.g. at the top of stairs)
  • Call an ambulance to arrange urgent transfer to hospital.
• Secure airway (insert a Guedel or nasopharyngeal airway) and resuscitate.
• Give oxygen if possible.
• Assess cardiorespiratory function and monitor blood pressure.
• Establish intravenous access.
• Consider the possibility of non-epileptic status.
• Emergency drug therapy. This depends on the stage;premonitory, established or refractory:
  • In the premonitory phase Diazepam 10-20 mg given rectally.
  • In the established phase intravenous diazemuls, repeated once 15 minutes later if status continues. Rectal diazepam will stop recurrent seizures in 70% of patients.⁵ Intravenous diazepam will end status in 60-80% of patients⁶ or midazolam 10 mg given buccally, may be easier to administer.
  • If seizures continue: Lorazepam (i.v.) should be used as first-line treatment in the established phase at a dose of 0.1 mg/kg (usually a 4 mg bolus, repeated once after 10-20 minutes; rate not critical). This has been shown to have a better efficacy than diazepam or phenytoin for stopping seizures and reducing the risk of status continuing.⁷
  • Long-term maintenance; anti-epilepsy drug therapy must be given in parallel with emergency treatment. The choice of drug depends on previous therapy, the type of epilepsy, and the clinical setting. Any pre-existing therapy should be continued at full dose, and any recent reductions reversed.

For sustained control or if seizures continue:

• Established status; Phenytoin infusion at a dose of 15-18 mg/kg and rate of 50 mg/minute, and/or Phenobarbitone 10-15 mg/kg at a rate of 100 mg/minute.
• Refractory status requires general anaesthesia. The refractory stage (general anaesthesia) is reached 60/90 minutes after the initial therapy. In some situations, general anaesthesia should be initiated earlier and, occasionally, should be delayed.

• Pulse oximetry
• Blood for blood gases
• Glucose level
• Renal and liver function
• Electrolytes
• Calcium and magnesium
• Full blood count
• Blood clotting
• Anti-epilepsy drug levels.
• 5ml of serum and 50ml of urine samples should be saved for future analysis, including toxicology, especially if the cause of the status epilepticus is uncertain.

• Administer glucose (50 ml of 50% solution) and/or intravenous thiamine (250 mg) as high potency.
• Pabrinex if any suggestion of alcohol abuse or impaired nutrition.
• Treat acidosis if severe.

• Establish aetiology. This is a common neurological problem in the elderly, with an underlying aetiology of stroke. Status epilepticus is associated with a high mortality.
• Identify and treat medical complications:
  • Chest x-ray to evaluate possibility of aspiration.
  • Other investigations depend on the clinical circumstances and may include brain imaging, lumbar puncture.
  • Status is associated with community acquired bacterial meningitis and fits in the acute phase of the illness are predictors of poor outcome.⁸

:

• Regular neurological observations and measurements of pulse, blood pressure, temperature.
• ECG, biochemistry, blood gases, clotting, blood count, drug levels.
• Patients require the full range of ITU facilities and care should be shared between anaesthetist and neurologist.
• EEG monitoring is necessary for refractory status. Consider the possibility of non-epileptic status.
• In refractory status epilepticus, the primary endpoint is suppression of epileptic activity on the EEG, with a secondary endpoint of burst-suppression pattern (i.e. short intervals of up to 1 second between bursts of background rhythm).

There is an incidence of 20-50/100,000 children per year. Fits are most commonly associated with febrile illnesses.The management of a child who presents with a tonic-clonic convulsion lasting more than 5 minutes should be the same as the child who is in established status.

• General measures are the same as outlined above for adults. A quick treatment response will produce the most effective outcome. There is increased morbidity and mortality associated with status lasting more than 60 minutes.⁹
• If immediate IV access : IV lorazepam 0.1mg/kg given over 30-60 seconds.
• If no IV access: diazepam 0.5mg/kg given rectally. Buccal midazolam may be easier.
• If seizure is continuing at 10min:
  • IV lorazepam 0.1mg/kg given over 30-60 seconds.
  • Paraldehyde 0.4 ml/kg given rectally (given with same volume of olive oil).
  • Phenytoin 18 mg/kg IV over 20 minutes or, if already on phenytoin, give phenobarbitone 20 mg/kg IV over 10 minutes. (use intraosseous route if still no IV access). Also Paraldehyde 0.4 ml/kg given rectally if not already given.
  • Call the on-call anaesthetist or intensive care medic.
• If seizure still continues:
  • Rapid sequence induction of anaesthesia using thiopentone 0.4mg/kg IV.
  • Transfer to intensive care unit.

This is less common than tonic-clonic status epilepticus. Treatment for non-convulsive status epilepticus is less urgent than for convulsive status epilepticus. Treatment should be considered as follows:

• Maintenance or reinstatement of usual oral anti-epileptic therapy.
• Use of intravenous benzodiazepines under EEG control, particularly if the diagnosis is not established.
• Referral for specialist advice and/or EEG monitoring.

• If the patient presents for the first time with status epilepticus, the chance of a structural brain lesion is greater than 50%.
• Mortality and the risk of permanent brain damage are increased with duration of the attack (especially if over 1 hour). Mortality rates are up to 5-10% in adults and 3% in children.

Good seizure control in pre-existing epilepsy.