Transcript Epilepsy update

Epilepsy update
Martin Sadler
Issues
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Who to treat and when to start?
Who needs investigations?
What to start with?
Treatment aims
New drugs
What to do when it all goes pear shaped?
Epilepsy surgery and gadgets
When to stop?
Who to treat
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One seizure or two? (24-64% 2 year risk of recurrence)
Benefits of treatment vs natural history
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(two year risk halved from 40 to 20%, but no effect on longer term remission rate)
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Overall prognosis (70% 5 year remission, 80% no seizures at 10 years,
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at 15 years 50% not on treatment)
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What to tell those who do not want treatment
Mind over matter
Who to investigate
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Any epilepsy commencing after 25 years of
age… imaging
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Epilepsy under 25 years which cannot be
classified as partial or generalised… EEG and
imaging
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Below 25, EEG and image if not IGE
What to start with
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Most adult seizures are focal onset
 Carbamazepine
 Valproate,
lamotrigine, oxcarbazepine,
?topiramate (less efficacy, more tolerability?)
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Generalised seizures
 Valproate
 Lamotrigine,
topiramate (?better tolerated, less ADR)
Women
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40% of patients are women of childbearing age
Women with epilepsy account for 0.5% of all
pregnancies
2% women with epilepsy have fits during labour
Uncontrolled epilepsy is a greater risk than drug
therapy to mother and baby
Teratogenicity risk
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Monotherapy 4-6%
Dual therapy 7-8%
Polytherapy 15-20%
NTD CBZ 0.5-1%
VPA 2%+ (? At above 1g/day)
Foetal anticonvulsant syndrome with orofacial
clefts, distal digital anomalies and learning
disability +/- cardiac defects attributed to several
AEDs.
What to do
Secure diagnosis
 Lowest effective doses
 Few drugs
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Add folate 5mg/d (NB distal neuropore closed 27d, palate
fused 47d)
New drugs… retreads
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Tegretol retard
 2/3
efficacy of “regular” CBZ dose for dose
 Drug levels may be of no value
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Epilim chrono
 Dose
for dose equivalence
 Once daily dosing
New drugs… old
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Lamotrigine
 Na
channels like CBZ & PHT
 Other mysterious mechanisms
 Slow
build up to avoid rash (up to 10%)
 Halve dose of LTG if adding VPA
 Use starter packs for adding into others
 NTD rate = CBZ
Further old new drugs
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Topiramate
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5 mechanisms of action
Long half life, can be used once daily
Efficacious
Recent monotherapy licence
Begin v low (15mg sprinkle) and build slowly
Wt loss 10-20% patients (? Add to VPA). Renal stones
Teratogenic? Animal studies: distal limb abnormalities
Increases oestrogen metabolism
New drugs in UK
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Oxcarbazepine
 “tegretol
lite”
 No self induced metabolism so rapid
introduction possible
 Maintenance 1.5X CBZ
 600-2400mg/day usual
 High
dose pill needed
New drug
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Levetiracetam
 Unique
mysterious mode of action
 Broad spectrum including in myoclonia,
absence and photosensitivity
 Effective
dose 1-3g/day
 ? Wt loss
 ?teratogenicity
Others
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Tiagibine
 Marred
by vigabatrin worries
 Raises GABA at GABAergic synapses
 Add in for focal onset seizures (50% seizure reduction in 40%
patients in studies)
 30mg
day divided doses usually
 No important interactions but half life shortened by
CBZ and PHT so tds needed (use 20mg tds)
Defunct drugs
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Vigabatrin
 Suicidal
inhibitor of GABA transaminase thus raising
GABA
 Effective AED
 Concentric field reduction in 40-60%
 If continued monitor fields
 No interactions
 No teratogenicity so far
 5%
every 6 months
depression (esp if rapid changes)
Surgery
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Effective if:
 Discrete
lesion
 Clinical seizure type and EEG consistent with
the lesion
 Not an “important” bit of brain
 Careful selection needed
 80%
seizure freedom
Vagal nerve stimulator
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Left vagal nerve wrapped by stimulator electrode
May be good for drop attacks
May reduce seizures in otherwise intractable
patients (similar to adding new AED)
Expensive
Buccal midazolam
As effective as rectal diazepam
 Easier to administer
 Off licence at present
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Epilepsy specialist nurse sends out
information on use