ER treatment of Epilepsy

Treatment of Epilepsy in ER Submitted to AskTheNeurologist.Com in 2007 Author Anon.

The first seizure
Is it really first event?
If established that it is, in fact first, unprovoked event decision to treat depends on
- risk factors for recurrence
- risks of drug treatment
- patient preference

Seizure recurrence
Over 50% of patients who will have recurrence following first seizure will do so within 6 months
Recurrence rate varies from 36 – 77%
If careful history taken to ensure seizure is definitely “ first ever” then recurrence rate drops to 35%
Recurrence rate following second seizure is 80-90%

Risk factors for seizure recurrence
History of prior neurological injury or lesion
History of epilepsy in a sibling
Transient neurological deficit ( Todd’s )
EEG with generalised epileptiform discharges

Treatment of status epilepticus
Acute emergency management
- Prevents injury
Rational drug administration
- Limits morbidity due to systemic changes or seizure-induced neuronal damage

Definitions
ILE: “ seizure that persists for a sufficient length of time or is repeated frequently enough that recovery between attacks does not occur”
Most literature specifies time period of 20-30 minutes as estimate of time necessary to cause injury to CNS

Operational definition
“ Continuous seizures lasting at least 5 minutes or 2 or more discrete seizures between which there is incomplete recovery of consciousness”

Predictors of outcome
Age
Cause - Metabolic
- Infection
- CVA
- Trauma
Known epileptic patients have best prognosis

Outcomes
Overall mortality is 20%
Patients whose first ever seizure is status epilepticus have substantial risk of future episodes and the developmennt of chronic epilepsy
Predominant factor affecting outcome is cause
Myoclonic status epilepticus after hypoxia carries especially grave prognosis
Duration of status epilepticus is correlated with neurological morbidity and lack of responsiveness to drug treatment

Assessment and supportive measures
ABC - protect airway
100 % O2
BP control
Monitoring - ECG
- BP
- ABG’s
- Biochemistry
- Body temperature

Glucose
Hypoglycemia should be excluded
Usually treat empirically with 50ml of 50% glucose
Should always precede glucose administration with 100mg thiamine IV

Blood pressure
Hypertension usually occurs early in course
Subsequently BP labile and often drops
Fluids and vasopressors may be required
Aim for high/normal range

Body temperature
May often be result of seizures themselves rather than co-existing infection
Should be treated with passive cooling

Systemic treatment
Avoid over-hydration ( cerebral oedema )
Blood tests ( including Ca, Mg)
Monitor oxygenation
Monitor rectal temperature

1 st line drug treatments
Benzodiazepines
- Diazepam vs Lorazepam
Phenytoin vs Fosphenytoin
Phenobarbital

Benzodiazepines Can be used alone Necessitates use of a second long-acting drug Longer duration of action Rapid redistribution into body fat Less rapid penetration into brain More rapid penetration into brain Less lipid soluble More lipid soluble Lorazepam Diazepam

Lorazepam
“ Despite their equivalence as initial therapies, lorazepam has a longer duration of antiseizure effect ( 12-24 hours ) than diazepam ( 15-30 minutes)…..lorazepam preferable to diazepam for the treatment of status epilepticus”

Fosphenytoin
Water-soluble prodrug form of phenytoin
Does not contain propylene glycol
( which is main limiting factor for rate of treatment as contributes to cardiovascular side effects)
Less irritant
Can be given at a maximum rate of 150 phenytoin equivalents / minute
Phenytoin itself may only be administered at a maximum rate of 50mg/min

Maximal brain concentrations of phenytoin
Attainable in 20-25 minutes when phenytoin infused at maximal rate
Attainable within 10 minutes when Fosphenytoin infused at maximal rates

Phenobarbital
“ Highly effective”
Recommend 20mg/kg at rate of 50 – 75 mg/min
Risk of apnea….especially if patient has received BZD’s

IV Valproic acid
Effective in some forms of status epilepticus
At time of publication insufficient experience available

Refractory status epilepticus
Failure to control seizures with BZD’s, phenytoin and phenobarbital
Requires administration of iv anaesthetic agent - Barbiturates
- Midazolam
- Propofol
EEG performed at 12hrs and thereafter every 24 hours

Recommend saline and dopamine infusion Myocardial depression Vasodilatation Decreased venous return Decreased cardiac perfusion Associated with profound systemic side effects Assessment clinical and on basis of EEG Potent Doses adjusted on basis of EEG responses Tachyphylaxis necessitates dose variation Pentobarbital Propofol Midazolam

Recommendations regarding Barbiturates
Severe hypotension requiring pressor therapy limits safety of barbiturates
Preferable to reserve anaesthesia with barbiturates for patients in whom midazolam or propofol fails

Submitted to AskTheNeurologist.Com in 2007 Author Anon.

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ER treatment of Epilepsy

by Richard Brown on May 03, 2007

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ER treatment of Epilepsy — Presentation Transcript