Brainstem dysfunction in patients with late-onset Lennox-Gastaut syndrome: Voxel-based morphometry and tract-based spatial statistics study

Case Report: Late-Onset Lennox-Gastaut Syndrome Treated With Stereotactic Electroencephalography-Guided Radiofrequency Thermocoagulation Before Craniotomy

The onset of Lennox-Gastaut syndrome (LGS), a severe epilepsy syndrome, is typically before 8 years of age. Late-onset LGS (with onset in adolescence and adulthood) is relatively rare clinically and has some differences from classical LGS. Herein, we describe the case of a patient with late-onset LGS and provide a literature review of such cases. The patient had focal epilepsy onset at 8 years of age. After a 9-year evolution, he suffered seizures of different types and had a diagnosis of late-onset LGS. Drug treatment was ineffective. Nothing was found on stereotactic electroencephalography (SEEG) and magnetic resonance imaging (MRI) during the course of the disease. After the second presurgical evaluation, we found a suspicious focus on high-resolution structural MRI which was verified by SEEG at last. After SEEG-guided radiofrequency thermocoagulation (RFTC), his seizures were controlled, and his cognitive function and quality of living clearly improved. However, his seizures recurred 2 years later, and he underwent left occipital resection. Thereafter, his seizures have been controlled until now. This case emphasizes the importance of high-resolution structural MRI in the treatment of LGS. Furthermore, it suggests that late-onset LGS may be caused by focal lesions and evolve from focal epilepsy. Thus, characterizing the clinical symptoms and performing individualized electroencephalographic follow-up are both very important. Additionally, the clinical outcome in this case implies the value and limitations of RFTC in patients with epilepsy and a clear focal lesion. Moreover, this case further supports differences between late-onset and classical LGS in terms of clinical manifestation, cognitive changes, prognosis, and treatment.

The Curious Case of Lennox-Gastaut Syndrome: Treatment-Resistant Seizures in a Patient With Autism Spectrum Disease With Lennox-Gastaut Syndrome

Lennox-Gastaut syndrome (LGS) is a childhood epilepsy disorder seen between the ages of one to eight years with the electroencephalogram (EEG) changes showing slow spiked-wave complex bursts or paroxysms of generalized fast activity and intellectual disability and often needing multiple lines of treatment. Autism spectrum disease (ASD) is rare but catastrophic comorbidity seen in a patient with LGS. We report an eight-year-old boy presenting to the emergency department with seizures and mental retardation. His first seizure was at the age of five months but was symptomatically treated without any specific diagnosis. On further investigation, the patient was diagnosed with LGS with concomitant ASD. The patient has successfully been treated for his treatment-resistant seizures and is now on regular follow-ups. This article aims to highlight this rare combination of LGS along with ASD and understand the disease course.

Late-onset Lennox-Gastaut syndrome: Diagnostic evaluation and outcome

Background

We describe the clinical features and outcome in patients with late-onset Lennox-Gastaut syndrome (LGS).

Methods

Adult patients evaluated between January 1, 2000, and March 1, 2017, who presented with onset of LGS ≥10 years were identified. Data abstracted included age at seizure onset, seizure types, etiology, treatments, EEG and neuroimaging results, cerebrospinal fluid (CSF) findings, and autoimmune evaluation.

Results

Ten patients (8 females) were identified. The mean age at onset of seizures consistent with LGS was 16.5 years (range, 10-32 years). Seizure types included tonic, atonic, and tonic-clonic seizures (all), myoclonic seizures (n = 3), and atypical absence seizures (n = 7). Five patients had normal intellectual function at onset. Prolonged video-EEG monitoring recorded seizures and generalized interictal epileptiform discharges in all. All patients had drug-resistant epilepsy (range of antiseizure drugs tried, 7-16). Two patients had a history of intrathecal methotrexate to treat acute lymphoblastic leukemia. Two patients had malformations of cortical development. CSF analysis (n = 5) showed a mild elevation in the protein level without other abnormalities. Autoantibody determinations in the serum (n = 4) or the CSF (n = 5) and genetic testing (n = 5) were negative. At final follow-up, all but 1 patient was disabled and required a caregiver, and none were driving. One patient died of probable sudden unexpected death in epilepsy (SUDEP).

Conclusions

Late-onset LGS represents a rare, treatment-resistant generalized epilepsy that is disabling and may be associated with progressive cognitive impairment. The elevated CSF protein level in our cohort could have been due to high seizure burden but increases the possibility of an inflammatory component to the pathophysiology of this disorder.