seizures

see also:

• drug-induced seizures
• paediatric seizures and paediatric patient information sheets
• Vic DHS - patient information sheet - seizures (pdf)
• febrile convulsions in children
• Is it really epilepsy?
• seizures due to severe acute hyponatraemia
• anticonvulsants
• neurology
• eclampsia
• AFTB Lectures - Mx of status epilepticus (2008)

• oxygen
• protect airway
• exclude hypoglycaemia early!
• iv access - consider bloods for U&E, Ca, PO4, glucose, and anticonvulsant levels if already on them
• cardiac monitor and oxygen saturation monitor when possible - usually after initial dose of 1st line anticonvulsant
• think about possible causes whilst resuscitation in progress (see below), in particular:
  • if hypoglycaemic, give iv glucose
  • if pregnant then consider eclampsia and magnesium Rx
  • drug-induced seizures may warrant different Rx or earlier intubation
  • not enough oxygen to brain will cause seizures - could it be secondary to hypoxia or hypotension?
  • Is it really epilepsy? - could it be pseudo-seizures - consider serum prolactin
  • if known to have severe hyponatraemia < 120mEq/L - give 3% saline boluses

• midazolam 0.15-0.3 mg/kg IM (or intranasally or 0.5mg/kg (max. 10mg) buccal) or diazepam 0.4 mg/kg rectally (max 10mg)

• iv benzodiazepines:
  • midazolam 0.1-0.3 mg/kg, or,
  • diazepam 0.15 mg/kg, or,
  • clonazepam 0.5 -1 mg, or,
  • lorazepam 0.1 mg/kg
• if no response within 5 minutes, repeat dose of benzodiazepine
• move to a monitored resuscitation cubicle

• if still convulsing after further 5-10min then start either:
  • iv phenytoin as long as NOT a drug-induced seizures or a heat stroke-induced seizure:
    • phenytoin 18 mg/kg (max. 1.2g) IV via syringe pump over 45-60min with 0.22 micron filter
      • max. infusion rate = 50 mg/min
      • can also be given via IMED diluted in 0.9% saline
      • NOT compatible with benzodiazepines or dextrose in same iv line
      • avoid in juvenile myoclonic epilepsy (JME)
  • iv phenobarbitone 20 mg/kg at 100 mg/min.
  • iv levetiracetam (Keppra) 25mg/kg (usually 1g in adults) over 15 min
    • although not well studies, appears to be as effective as phenytoin but without the iv line incompatibility issues but may not be as effective as sodium valproate (Epilim) as a 2nd line for status
  • iv sodium valproate (Epilim) 20-40mg/kg load dose given at 5mg/kg/min in adults
    • may be preferred as a non-sedating option for focal or myoclonic status, and is preferred over phenytoin for primary generalized epilepsies
    • may need higher dose if patient has been on enzyme inducing anticonvulsants
    • BUT risk of hepatic dysfunction and coagulopathy are important considerations in patients with active bleeding or those with liver disease or aminoacidopathies
• consider aetiology and possible specific therapies (see below)

• consider pyridoxine (100mg IV) in young infants with seizures refractory to standard anticonvulsants.
• consider more phenytoin to 30mg/kg total dose if not C/I
• consider more midazolam
  • in children, if 2 appropriate doses fail to terminate the seizure, further doses are unlikely to be effective and increase the risk of respiratory depression.
  • midazolam infusion 1 - 5 mcg/kg/min might be an alternative to RSI intubation with supervision by senior staff.
• rapid sequence induction (RSI) for emergency intubation intubation with induction dose then infusion of either:
  • thiopentone
  • propofol 3-5 mg/kg, then infusion at 30-100 μg/kg/min;

• known epileptic - ? compliance, ? toxicity
• hypoglycaemia
• hypoxia
• head trauma
• meningitis / encephalitis / HIV / AIDS
• drug-induced seizures especially tricyclic antidepressant overdose
• drug withdrawal - ethanol (alcohol and alcohol withdrawal), benzodiazepines, anticonvulsants, opiates and opioids, cocaine
  • hopefully no-one gave a benzodiazepine antagonist to a polypharmacy OD which may precipitate a withdrawal seizure or remove the anticonvulsant benefits of benzodiapines from the cocktail.
• metabolic - hyponatraemia, hypocalcaemia, hyperthyroidism, uraemia, eclampsia
• intracerebral event - stroke (CVA), complication of tumour, vasculitis
• causes of paediatric seizures by age

• refer to 1st seizure clinic
• refer to EEG
• refer for MRI scan
• in Victoria:
  • Commercial drivers are required to be seizure free for 10 years
  • Private drivers may not be allowed to drive for various periods depending upon circumstances of the seizure but it is usually 12 months of seizure-free period
  • see https://transport.vic.gov.au/registration-and-licensing/licences/medical-conditions-and-reviews/medical-conditions/seizures-and-driving
  • see https://austroads.gov.au/publications/assessing-fitness-to-drive/ap-g56/neurological-conditions/seizures-and-epilepsy

• in patients with epilepsy, it seems that when the two hippocampi start communicating with each other then this raises the risk of a seizure within the next hours or day and this pattern can be detected with snapshot 90sec EEG analysis ¹⁾

• AFTB lectures - status epilepticus
• RCH clinical guidelines - Mx of afebrile seizures