小児てんかんにおける抗けいれん剤の新しい断薬方法についての臨床的および脳波学的検討

抄録

The subjects of this study were 140 epileptic patients (80 men and 60 women) who had been observed for over two years, and had satisfied the following requirements for discontinuation of their anticonvulsants medication: (1) no clinical seizures for 3 or more years due to therapeutic administrations of anticonvulsants; and, (2) EEG recordings, at 6-month intervals, that showed no recurrence of epileptiorm discharges when either awake or asleep.
These patients were administered anticonvulsants which were reduced to a dose amounting to one-fourth their previous therapeutic level every two months until complete discontinuation of medication at 6 months. They were examined with regard to this course and their clinical background factors. Additionally, EEGs of 106 of these subjects were examined for 3 consecutive days during a suspension of medication, so as to evaluate the EEG findings and to determine whether EEG findings would enable us to form a prognosis of their condition.
The results obtained were as follows.
1) The incidence of clinical seizures and abnormal EEGs after discontinuation of anticonvulsants was 5%. Excluding the involvement of seizure-inducing factors, the rate of relapse was 1.4%.
2) All cases of relapse after discontinuing anticonvulsants occurred within a year.
3) Adolescence was not necessarily a risk factor in discontinuing anticonvulsants.
4) After discontinuation of anticonvulsants, factors indicating a good prognosis included: (1) the successful control of clinical seizures in less than a year after the start of anticonvulsant therapy; (2) the elimination of epileptiform discharges in less than 3 years after the start of anticonvulsant therapy; (3) an interval of less than 2 years between the suppression of clinical seizures and the elimination of epileptic discharges after the start of anticonvulsant therapy.
5) There was no relapse of clinical seizures in any subject during the 3-day period when medication was suspended. The EEG findings recorded during this period served, to a degree, as an index for the relapse of clinical seizures, and for the incidence of abnormal EEG findings after reinstitution of anticonvulsants.
Thus, when no specific seizure-inducing factors were involved, a relapse of clinical seizures and abnormal EEG findings were extremely rare in those patients who had satisfied our initial requirements and from whom medication was withdrawn in this 6-months program of gradual dose reduction.