Treatment Strategy for the Patient with Hippocampal Sclerosis Who Failed to the First Antiepileptic Drug

Despite many epilepsy patients respond to antiepileptic drugs (AED) successfully, more than 30% of patients continue to have seizures on multiple AEDs. The refractory epilepsy increases the risk of cognitive deterioration, psychosocial dysfunction, and sudden unexpected death of epilepsy patients (SUDEP). It is important to identify refractory epilepsy early and make the goal of epilepsy treatment as the prevention of decline in social, vocational, and cognitive performances and minimizing the risk of accident or SUDEP. The syndrome of medial temporal lobe epilepsy with hippocampal sclerosis (MTLE with HS) is often resistant to AEDs, and surgically remediable. Initially well-controlled seizures often become intractable to AEDs. There are progressive behavioral changes including increasing memory deficit. Surgical outcome is also worse with longer duration of epilepsy or increasing age at surgery, which suggests that MTLE is a progressive disorder. Some emphasized the ultimate intractability of MTLE in which intractability of MTLE could be evident only after some years following initial diagnosis. However, when patients considered to have intractable epilepsy were followed up for a long period of time, many of them experienced seizure-free state. Some studies clearly demonstrated the wax and wane courses of treatment response in epilepsy. Late remission could be achieved up to in a half of patients. Thus intractable state is not a static condition but a fluctuating one and initial refractoriness does not necessarily mean the final intractability. Even though the chance of seizure remission with AEDs is not high for MTLE, some of them do well respond to drugs. It is even possible to withdraw AEDs for a few patients. Though epilepsy surgery is very effective method to treat MTLE, considering the fluctuation courses of intractability and the possibility of delayed remission, at least two adequate AEDs could be applied to the patients before surgery. However, medical intractability becomes evident by definition, it is not reasonable to delay epilepsy surgery.