Emergency Seizure Management

Types of seizure considered an emergency

- cluster epileptic seizures

• more than 2 seizures in 24hr with complete recovery inbetween

• may be regular type for the patient

- status epilepticus

• sustained seizure activity >5 mins,

• or cluster seizures w/o complete recovery inbetween

what does seizure activity in close succession create

- vasogenic and cytotoxic oedema - promotes more epileptic activity

- mortality rate 25.3-38.5% - irreversible brain damage - oxygen deprivation, systemic complications

How could you medicate an emergency seizure patient in hospital ? different ways

- oral bolus/ loading

- rectal bolus

- intranasal bolus

- IV bolus

- IV loading

- CRI

How could you medicate an emergency seizure patient at home? different ways

- oral bolus/ loading

- rectal bolus

- intranasal bolus

short acting medications in emergencies for seizures

- benzodiazepines

- ketamine

- medetomidine

- propofol

long acting medications in emergencies for seizures

- levetiracetam

- phenobarbitone

mechanism of action of benzodiazepines

Binds to GABA-A receptor:

increases Cl- influx into post-synaptic neuron

causes hyperpolarization -> decreases neuronal excitability

bzd examples

Midazolam, diazepam, Lorazepam

pharmacokinetics of benzodiazepines

Routes of administration: IV, IM, Intranasal, rectal (slow)

Time to effect: 1-5 minutes depending on route (IV <3 mins, rectal has poor efficacy).

Duration: 20-30 minutes

Metabolism: Hepatic

In hospital and at home administration available

dosing of benzodiazepines

for your info

mechanism of action of ketamine

Ketamine is a non-competitive NMDA receptor antagonist

Blocks the NMDA receptor

Decreased influx of Na+ and Ca2+ via ion channel into post synaptic neurone

- No depolarization

- No neuronal excitation

pharmacokinetics of ketamine

Routes of administration: IV

Time to effect:

dosing of ketamine

for your info

pharmacokinetics of (dex)medetomidine

Routes of administration: IV, IM

Time to effect: 1-2 minutes (IV)

Duration: 1-2 hours (peak effect 5-15 minutes)

Metabolism: Hepatic

In hospital administration only

sedation for patient, not anti-epileptic (for post ictal signs)

dosing of (dex)medetomidine

for your info

mechanism of action of propofol

Binds to GABA-A receptor: different site to benzos

increases Cl- influx into post-synaptic neuron - increasing duration of channel opening

causes hyperpolarization ->decreases neuronal excitability

pharmacokinetics of propofol

Routes of administration: IV

Time to effect:

dosing of propofol

for your info

to effect

mechanism of action of Levetiracetam

Binds to synaptic vesicle protein 2A in the pre-synaptic neuron:

This modulates release of excitatory neurotransmitters (glutamate) into the synaptic cleft

decreased glutamate release -> decreases neuronal excitability

pharmacokinetics of Levetiracetam

Routes of administration: IV (hospital), oral, rectal, (IM)

Time to effect: <5 minutes (IV), 1-2 hours (oral)

Duration: 4-6 hours

Metabolism: renal excretion without major metabolism

Can be given in hospital or at home

dosing of Levetiracetam

for your info

mechanism of action of phenobarbitone

Phenobarbitone is a GABAa receptor agonist. They prolong the duration of GABAa chloride channel opening.

Binds to GABAa receptors on Cl- channels

Influx of Cl- into post-synaptic membrane

Hyperpolarisation

Harder for the threshold of that neuron to be reached

Action potentials are not propagated

pharmacokinetics of phenobarbitone

Routes of administration: IV, oral

Time to effect: 5-20 minutes (IV), 4-8 hours (oral)

Duration: 12 hours

Metabolism: hepatic metabolism

In hospital administration only (IV)

can load→ lot in short succession so dont need to wait for 3wks for it to build up

dosing phenobarbitone

for your info

emergency = IV

Loading 20mg/Kg/day - 2-3mg/kg bolus

initial management of emergency seizure

1. IV Access

2. Administer benzodiazepine bolus

3. Haematology, biochemistry and electrolytes

4. Administer a longer acting AED

5. IVFT

6. Consider whether this patient needs a CRI starting

7. Consider if this patient needs to be loaded with a longer acting AED

mneumonic to remember management of emergency seizure

I Bet Bigfoot Makes Fantastic Ice Lollies

IV, Benzos, Bloods, Medications, Fluids, Infusions, Loading

why is IV access needed in seizure patients ?

- first - admin bolus of benzodiazepines IM, helps you place IV

- vital for cluster and status - require IV meds and fluids

- take blood IV

continue care

which Benzodiazepine is your choice for Bolus ?

what do you do once you have given it?

midazolam = more potent for emergency

- start a stopwatch

- gives you 20 minutes to execute rest of plan

- successful response - seizure cessation

Blood decisions for seizuring patients

- naive seizure patient - systemic screen for reactive causes of seizures

- access the safety of AED (liver for pheno)

- If patient is long term AED - take serum sample before IV admin occurs

what on bloods would alter your decisions on medications ?

liver parameters - phenobarbitone

take serum before bolus - so not altered

How do you decide which long acting medication to give: levetiracetum

Levetiracetam: First choice - safety

- Initially 60mg/kg bolus followed by 20mg/kg TID

- Can go up to QID

- Shown to be safe up to 70mg/kg QID dosing

How do you decide which long acting medication to give: phenobarbitone

Phenobarbitone:

- Initially 3mg/kg bolus

- If naïve 3mg/kg IV TID for first 24hrs then BID dosing.

- Loading do not exceed 20mg/kg/day, 2-3mg/kg boluses spread out by at least 20-minutes between.→ give enough time to set in

veteran patient: on pheno long term

- wait for serum level before adjusting,

- cautious use can be implemented.

- Start with the normal mg/kg IV dosing following the initial bolus at same time of day.

- avoid phenobarbitone toxicosis

Is fluid therapy indicated in seizuring patients? why

yes

- Help systemic perfusion

- Restores losses may have had during seizure

- Seizures cause huge metabolic demand

- Hypovolemia -> hypotension and decreased cerebral perfusion

- Decreased cerebral perfusion can lead to brain ischemia and neuronal injury

What options do you have for CRI?

- BZD

- ketamine

- (dex)medetomidine

- propofol

why use cri

• contantly giving seiure meds

• dont ened repetitive bouse

• buying time for longer time drugs to kick in —————-

How do you load phenobarbitone and when?

- how well have they responded to previous treatments ?

- are they still having repetitive seizures ?

what are the risks of loading with pheno

- Neurological abnormalities

- comatosed

maximum 20mg/kg/day - hospitalise while side effects wear off

What is weaning in regards to seizure medication?

Ideally 12-24hrs on CRIs seizure free before start weaning medications

Then decrease CRIs incrementally from the last one added to the first one added

Decrease by 25-50% of the dose every 4-6hrs

Complications of seizures

Cushing's reflex (bradycardia, hypertension, worsening neurological status)

Aspirational pneumonia - gag impacted by seizure and medication

Lacerations to tongue

Intubation

Ventilation

Post-ictal signs vs permanent neurological dysfunction→ see back

Phlebitis

Hyperthermia

Death

At home management of emergency seizures

- midazolam - Intranasal (better response, tip on device vaporises)

- rectal diazepam (dose is fixed in applicator, have to give multiple, but is the only liscenced one)

-Levetiracetam

how use levetiracetam at home

- If naïve start pulse therapy so 60mg/kg bolus and then 20-30mg/kg TID until seizure free for 48hrs.

- If veteran 60mg/kg bolus and can increase to 60mg/kg QID for 48hrs until seizure free.

• Happened before

• What look like

• Access to meds?

• Giving whats been prescribed

• How recovered, complete?

Probs post ictal -> resee in 7 d

Diagnostics: biochem and haem, eletrolytes, neuro exam

im midazolam

Get iv acess, bloods from catheter

Wait for bloods,

Look out for seizure activity: focal, twitich of face, generalised tonic clonic

 

• Fast acting as bolus: more midazolam,

• Follow up pehno -> act in 20 mins

On midazolam cri

Ket bolus to work quick-> monitoring: breathing, gag affected, sedated now

Thhink abt loading pheno at this point bc having seizure events despite all the meds

Wean of cri -> another 24hr in hospital at least

Send home with phenobarbitone

Test bloods in 3 weeks

And send rectal or nasal midazolam-> administer immediately when seiure starts -> bc can take 5 mins to work