Page 361 - ILAE_Lectures_2015

(hazard ratio [HR] 2.0, 1.1-3.6; P = 0.02). The longer a person remains seizure free the less
likely they would relapse, while conversely the longer seizures persisted post-operatively the
less likely seizure remission would be achieved44.

In summary, in appropriately selected patients, surgery is four times more likely to render
patients seizure-free than medical treatment alone.

Prognosis in those with intractable epilepsy

Studies suggest that failure to control seizures with the first or second AED implies that the
probability of subsequent seizure control with further AEDs is slim27. This can lead to clinical
nihilism when dealing with such patients in clinic. A recent series of papers suggests,
however, that such a view is overly pessimistic. In a retrospective analysis of the effect of
265 medication changes in 155 patients with uncontrolled epilepsy of at least five years’
duration, 16% of all patients were rendered seizure free (12 months or more) following a drug
introduction while a further 21% had a significant reduction of seizure frequency. Overall
28% of the cohort was rendered seizure free by medical changes45.

In another study a group of 246 patients with refractory epilepsy was followed for three years.
Excluding those who became seizure free because of surgery, 26 (11%) became seizure free
(six months’ terminal remission) as a result of medication change (addition of a new AED or
dose change). No single AED was associated with a statistically significant probability of
inducing seizure freedom. Patients with mental retardation were statistically less likely to
achieve a remission. Overall approximately 5% per year became seizure free, highlighting
the fact that, irrespective of the number of AEDs previously tried, there is still a possibility
of inducing meaningful seizure remission in this population46.

The probability of seizure relapse following remission was retrospectively studied in a cohort
of 186 patients with intractable epilepsy who were followed for a median of 3.8 years. Overall
20 patients achieved a remission of ≥12 months with a 4% probability of remission per year.
Of these, five subsequently suffered a relapse with the estimated cumulative probability of
relapse 33% at two years and 44% at three years. No clear predictors of remission or
subsequent relapse were identified47.

In summary, approximately 4−5% a year of those with refractory epilepsy will achieve a
remission of 12 months on medication, although more long-term follow-up demonstrates that
approximately one-half will subsequently relapse48.

Conclusions

The overall prognosis for people with newly diagnosed epilepsy is good, with 60−70%
becoming seizure-free, many of whom doing so in the early course of the condition. The
probability of obtaining seizure freedom is particularly high in those with idiopathic
generalised epilepsy and normal neurological examination. For those who continue to have
seizures despite multiple appropriate AED treatments, in appropriate candidates epilepsy
surgery is four times more likely to render seizure freedom than continued medical treatment
alone. Despite this, medical changes will achieve a remission of 12 months in 4−5% a year
of those with seemingly intractable epilepsy.

References

1. SANDER JW. Some aspects of prognosis in the epilepsies: a review. Epilepsia 1993;34:1007-16.
2. KWAN P, SANDER JW. The natural history of epilepsy: an epidemiological view. J Neurol Neurosurg

Psychiatry 2004;75:1376-81.