Page 265 - ILAE_Lectures_2015

When to start antiepileptic medication – rare seizures

People who have who have long gaps between seizures may be treated differently to those
with frequent seizures, depending on the type of seizure. For instance a patient with GTCS
at, say, five-year intervals should in most circumstances be recommended AED treatment
because of the risk of injury or SUDEP; a patient with only rare complex partial seizures, or
even more frequent simple partial seizures may take a different view. A risk of a GTCS and
attendant SUDEP risk should still be discussed in these cases. In the past, fear that having a
seizure might make another more likely (similar to kindling in the rat) led some to
recommend early treatment. But the multicentre study of early epilepsy and single seizures
(MESS)3 showed that the likelihood of remission is the same if treatment is immediate or
deferred. AEDs do not appear to alter the prognosis of the underlying condition.

When to start antiepileptic medication – recurrence risk

The decision to start medication is a balance between the risk of recurrent seizures and the
requirement for regular medication with all this entails. The risk is greatest close to the first
seizure; individuals seen months after a seizure are already low risk. Factors associated with
higher risks of recurrence include: an underlying structural abnormality, learning difficulties
and spike-wave on EEG4,5. The DVLA now recognise this evidence and allow individuals
who have had a single seizure in whom investigations are normal and the risk of recurrence
is deemed to be low (<20% per annum) to drive using a Class 1 (not HGV) licence after six
rather than 12 months.

Acute symptomatic and provoked seizures

Seizures associated with acute insults to the brain, e.g. infection or trauma, need to be treated
but AED treatment should not be given to prevent the development of epilepsy because this
is ineffective6 and AEDs should be discontinued within or at most six months after the insult.
Seizures exclusively provoked by external factors, e.g. alcohol withdrawal, should be treated
by avoiding the provocation.

Deciding to start

The diagnosis of epilepsy can be straightforward, but may be problematic. Unwitnessed
attacks and subjective symptoms such as fear or panic can cause difficulties. In almost all
cases it is sensible to wait until the diagnosis is beyond reasonable doubt before starting
medication. And it should be noted that some people choose not to take medication, e.g. a
young woman with focal seizures and little if any loss of awareness who does not want to
drive and is about to start a family. Relevant factors such as lifestyle, work, personal safety,
driving and responsibilities for others should be discussed with the individual when deciding
whether to start medication or not. This is not a consultation that should be hurried.

The aim of antiepileptic medication is to prevent seizures with minimal discomfort to the
individual. All AEDs have the potential for side effects and some have significant interactions
with other medication. Choice of AED will depend on these and the efficacy of the drug.
Choice of AED is determined to an extent by the seizure type(s) and epilepsy syndrome (see
Tables 1 and 2). A single AED should be started in a low dose and escalated – slowly – to a
maintenance dose (see Table 3). Rapid escalation is more likely to be associated with acute
idiosyncratic and dose-related side effects such drowsiness or rash that can dishearten the
individual or put them at risk of iatrogenic harm. Many individuals will respond to a low dose
of an appropriate AED. Indeed the response to the first well-tolerated AED helps to predict
the outcome7. About 50% will enter a remission quickly, of the rest 2030% will enter