Authors :
Presenting Author: Yu Kitazawa, MD, PhD – Yokohama City University Graduate School of Medicine
Mutsuki Takeda, MD – Yokohama City University Graduate School of Medicine
Masaki Sonoda, MD, PhD – Yokohama City University Graduate School of Medicine
Yosuke Kudo, MD, PhD – Yokohama Municipal Citizen’s Hospital
Keisuke Morihara, MD, PhD – Yokohama City University Graduate School of Medicine
Yosuke Miyaji, MD, PhD – Yokohama City University Graduate School of Medicine
Yuichi Higashiyama, MD, PhD – Yokohama City University Graduate School of Medicine
Katsuo Kimura, MD, PhD – Yokohama City University Medical Center
Naohisa Ueda, MD, PhD – Yokohama City University Medical Center
Hiroshi Doi, MD, PhD – Yokohama City University Graduate School of Medicine
Fumiaki Tanaka, MD, PhD – Yokohama City University Graduate School of Medicine
Rationale:
Lennox-Gastaut Syndrome (LGS) is a childhood-onset developmental and epileptic encephalopathy characterized by drug-resistant seizures and distinctive electroencephalographic (EEG) findings that often persist into adulthood. Fenfluramine (FFA), formerly used as an appetite suppressant, has recently been approved for the treatment of LGS and has shown promising efficacy. However, many pediatric patients diagnosed using classical criteria do not meet the updated criteria defined by the International League Against Epilepsy (ILAE), complicating the clinical application of FFA. This study aimed to assess how well previously diagnosed adult LGS cases align with the updated ILAE criteria.Methods:
We retrospectively reviewed adult patients with LGS, diagnosed using classical criteria who visited our clinics at least once in 2024. Patient demographics, seizure types, and EEG findings were analyzed according to the updated ILAE diagnostic criteria, which require: (1) seizure onset before 18 years of age; (2) must include tonic seizure; and (3) EEG records demonstrating both slow spike-and-wave complexes (SSW) and generalized paroxysmal fast activity (GPFA).
Results:
Eighteen adult patients were included, with a median age of seizure onset of 0 years. All had intellectual disability and a history of multiple generalized seizure types. Sixteen had a history of tonic seizures. Tonic seizures persisted in 15 patients; one achieved seizure freedom. SSW were observed in all EEG records, while GPFA was present in 11 patients. According to the updated ILAE criteria, 11 of 18 patients fullfilled the updated diagnostic criteria. FFA was prescribed for 10 patients. Notably, FFA contributed to a seizure frequency reduction of more than 25% in at least one seizure type even in cases that did not meet the updated criteria.Conclusions:
A significant proportion of adult LGS patients did not fulfill the updated ILAE criteria. While these criteria refine the diagnosis of LGS, their strict application may limit access to syndrome-specific medications such as FFA and rufinamide (RUF). Nonetheless, seizure reduction was observed in patients treated with FFA based on classical diagnostic criteria, as demonstrated in our cohort. Further studies are warranted to support broader access to FFA and RUF for patients with LGS-like epilepsy.Funding:
JSPS JP19K17039 (to Y.K.)