The problem of the drug-resistant epilepsies

For the majority of patients with epilepsy, the prognosis for seizure control is very good; however, refractory epilepsy develops in about 20-30% of patients and represents a significant challenge for both clinical management and for research. Physicians treating epilepsy are often asked to predict prognosis and make decisions about commencing and withdrawing treatment. Practice can be guided by epidemiological studies of prognosis. It seems that prognosis depends largely on the aetiology of the seizures and the clinical background of the patient rather than on the seizures themselves or the treatment prescribed. Aetiologies are, however, not the sole determinant of outcome and response to treatment and unknown factors must exit. It is likely that some of these unknown factors are genetically determined but this needs confirmation. The search for these unknown factors that may determine intractability in epilepsy is a very exciting prospect, which may prove to be multifactorial. In some patients, epilepsy may indeed become resistant to treatment whilst in others the propensity for intractability to the drugs currently available may be part and parcel of the condition. Further research is urgently needed to elucidate the full range of mechanisms that lead to drug resistant epilepsy.