Abstracts

Rationale: Lennox-Gastaut syndrome (LGS) is a catastrophic childhood epilepsy that is defined by a triad of symptoms: multiple seizure types (myoclonic jerks, atypical absences, head drops, or falls), slow spike-and wave EEG disturbance of about 1.5 to 2.5 Hz. and mental retardation. The etiology of LGS is variable. Most cases (30 75%) of patients with LGS are remote symptomatic and only about one third of cases are cryptogenic. Unlike the prognosis for other childhood epilepsies, the outcome for children with LGS is not favorable. The mortality rate is from 4 to 7% and the outcome of symptomatic LGS is as bad as cryptogenic LGS. We reviewed the evolution and outcome of LGS symptomatic to hypothalamic hamartoma (HH) and compared it with prior published outcome of cryptogenic and symptomatic LGS. Methods: Data was obtained from our HH epilepsy surgery database at the Barrow Neurological Institute between 2003 and 2011. Children with LGS symptomatic to HH were identified. Demographic details, seizure history, EEG findings, postoperative follow up data were evaluated. Patients were classified with LGS if they had the triad of refractory epilepsy, developmental delay or mental retardation and at least one EEG showing <3 Hz slow spike-and-wave discharges.Results: In the last eight years 21 out of 159 patients (14%) with HH had clinical features consistent with LGS. At the last clinic visit, the median age of the 13 male and 8 female patients was 7 years (range 4 months 11 years). All patients had refractory epilepsy associated with HH. The initial seizure type in 18 patients (86 %) was gelastic. Other seizure types were: myoclonic jerks (82%), atonic/tonic (76%), absence (21%), infantile spasms (24%) and generalized tonic clonic seizures (62%). Six of the 21 patients had preceding infantile spasms. All patients had developmental delay and/or mental retardation. 9 of 21 (44%) had behavioral issues including rage attacks. Slow spike and wave EEG changes with different frequencies ranging from 1.5 up to 3 Hz were seen in all patients at some point of their management. All of them underwent different surgical resections including endoscopic (11), transcallosal (9), gamma knife ( 14), orbitozygomatic (2). 23 % (5 out of 21) were seizure free 42% ( 9 out of 21) had >90% seizure reduction. Parental perception of their child s overall postoperative behavioral functioning compared with the preoperative baseline functioning suggested improvement in 19 (88%) of the patients. Compared to prior published outcome of symptomatic LGS our study indicates a better outcome of LGS symptomatic to HH. However the overall seizure freedom rate was lower than our previously reported overall HH seizure free rates of 49 to 55%. Conclusions: LGS symptomatic to HH have better post-surgical outcome compared to prior published cryptogenic and symptomatic LGS, probably due to the presence of a clear operable lesion (the HH). However compared to overall HH post-surgical outcomes, they tend to not be as good confirming the concept that LGS represents an overall more severe epilepsy syndrome.