Effect of adrenocorticotropic hormone therapy for epileptic spasms developing after the age of 1 year

PURPOSE Epileptic spasms sometimes begin after the first year of life, and such seizures are recognized as late-onset spasms (LOS). The prognosis of LOS is poor, and a treatment strategy has not been established. This study aimed to assess the short- and long-term effects of adrenocorticotropic hormone (ACTH) therapy for LOS. METHODS We investigated the rate of LOS in 22 patients (14 boys and 8 girls) treated with ACTH therapy. The age at onset of LOS and at the start of ACTH therapy ranged from 12 to 94 months (median, 31.6 ± 22.1 months) and from 12.5 to 116 months (median, 37.5 ± 23.7 months), respectively. We investigated the response rate of LOS treated with ACTH therapy, and compared the clinical features between responders (short-term) and nonresponders. RESULTS Nine (41%) of the 22 patients showed cessation of epileptic spasms within 3 months. The epileptic spasms ceased in four of these nine patients for more than 1 year. The age at onset of LOS was significantly associated with short-term seizure cessation (p<0.05). Patients who achieved short-term cessation of seizures received ACTH therapy within 6 months from the onset of LOS. CONCLUSION ACTH therapy is a potentially effective treatment when started within 6 months from the onset of LOS. A younger age at onset of LOS is associated with a favorable outcome.