The clinical features and long-term follow-up of vitamin B6-responsive infantile spasms in a Chinese cohort

Objective To analyze the clinical features, treatment, and prognosis of patients with vitamin B6 responsive infantile spasms (IS). Methods The clinical features, genetics, and follow-up data of 30 patients were collected and analyzed. Results The age of epileptic spasms (ES) onset was from 3 months to 12 months. They all received high doses of vitamin B6 at different times after the onset of ES, ranging from one day to five months. ES were controlled within 11 days in 93% (28/30) patients, and as late as one month and two months in the other two patients. Of the 28 patients with follow up EEG results, 26 showed normal, and 81% (21/28) had suppressed epileptic discharges within six months. To the last follow-up, seizures were controlled well in 29 surviving patients, and 21 patients were able to deactivate from all medications. Sixteen patients showed varying degrees of developmental delay after onset. After seizure control, the psychomotor development was delayed in 7 patients (one died) until the last follow-up. Compared with others, patients with severe developmental delay took longer for their EEG to return to normal, and their vitamin B6 therapy was stopped later or even failed to stop. Conclusions An observation period of 1-2 weeks is essential to identify patients with vitamin B6 responsive IS. The treatment time could be extended according to the treatment response and EEG changes. Neurodevelopmental outcomes and prognosis of vitamin B6 responsive IS were relatively favorable.
Keywords: Vitamin B6, Infantile spasms, West syndrome, Epileptic spasms, Hypsarrythmia