Abstract
Topiramate is a novel anticonvulsant with diverse mechanisms of action, including enhanced GABA activity, voltage-dependent sodium channel stabilization and antagonism of kainate activity [1]. A previous study reported adjunctive topiramate may be therapeutically beneficial for paediatric bipolar disorder [2], but its therapeutic role in chronic mania is yet to be reported.
A 13-year-old boy, with a history of normal development, presented with organic mania (post-encephalitic) of 5-years duration that responded poorly to a 4-month trial of valproate 1000 mg/day and olanzapine 20 mg/ day. In the past, he had failed to respond to various antipsychotic medications or to lithium monotherapy. On admission, he exhibited manic symptoms and scored 26 on the Young Mania Rating Scale (YMRS) [3]. He was commenced on lithium 1500 mg/day (serum level: 1.04 meq/L) in addition to valproate 1000 mg/day (serum level: 105 ∝ g/mL) and olanzapine 25 mg/day. Due to poor clinical response, after 4 weeks, lithium was discontinued and carbamazepine was added. Carbamazepine was gradually increased to 800 mg/day but it too was ineffective and was discontinued after 4 weeks. During this period, his valproate was increased to 1200 mg/day and he was evaluated for clozapine trial. Electroencephalogram showed frequent focal (bifronto-central regions) sharp and slow (delta) waves and infrequent generalized slow waves. His MRI showed an area of porencephaly in the right occipital lobe.
Topiramate was commenced at 25 mg twice daily and increased to 50 mg twice daily in a week. Within a week of topiramate 100 mg/day, his manic symptoms significantly improved, along with reduction in YMRS score to 13. His total YMRS score decreased to 4 during the second week and he evidenced no significant side-effects.
Vieta et al. [4] reported that topiramate's therapeutic effects in bipolar disorder usually occur in 2–6 weeks. The clinical response of our patient began at the end of the first week and became pronounced during the second week of treatment. This report suggests topiramate may be considered a therapeutic option for chronic mania in young patients, particularly for those with EEG abnormalities.