The occurrence, outcome, and prognostic factors of infantile spasms (IS) and Lennox-Gastaut syndrome (LGS) were determined in children treated in the Department of Pediatrics, University of Oulu, Finland, from Jan 1976 to Dec 1993. Thirty seven had IS (0.41/1000 live births) and 25 had LGS (0.28/1000 live births). Ten (27%) of the patients with IS who later developed LGS (40% of LGS cases) had symptomatic epilepsy, were mentally retarded, and their seizures were uncontrolled at 10 year follow-up. Symptomatic epilepsy (30 (81%) IS and 17 (68%) LGS) had congenital or genetic etiologies in almost all cases (87% of IS, 100% of LGS). Cryptogenic epilepsy in 7 (19%) of the IS cases had a favorable prognosis, whereas in 8 (32%) of LGS cases, a cryptogenic etiology did not decrease the risk for a poor outcome. The majority received ACTH and polytherapy. [1]
COMMENT. The prevalence of infantile spasms (IS) in a primary university pediatric population in Finland is 0.4/1000 live births and that of Lennox-Gastaut syndrome (LGS) is similar. IS evolves into LGS in 27% of cases and these are symptomatic epilepsies, with a poor prognosis. Cryptogenic etiology has a favorable prognosis for IS but not in LGS cases.
Vigabatrin in the treatment of infantile spasms has been studied retrospectively in 25 infants (19 symptomatic, 6 cryptogenic cases) followed at the Children’s Hospital of Michigan, Detroit, MI. [2]. Clinical improvement was obtained in 16 (64%), and EEG improvement in 17 (68%). EEG and cognitive decline and/or more frequent spasms occurred in 7 (28%), often associated with larger VGB doses (>100 mg/kg daily). Smaller doses and EEG monitoring are recommended, since EEG and cognitive deterioration may occur despite clinical control of spasms.
Efficacy of Lamotrigine in refractory neonatal seizures of unknown etiology is reported in a single newborn treated at the Royal Alexandra Hospital for Children, Parramutta, NSW, Australia [3]. The EEG showed a burst-suppression pattern, and seizures were mainly generalized. Conventional AEDs were ineffective, vigabatrin (105 mg/kg/d) was partially effective, and the addition of lamotrigine (4.4 mg/kg/d) was followed by a sustained seizure control.