Abstracts

Rationale: Status epilepticus (SE) is one of the most frequent neurologic emergencies in childhood. Effective treatment options in patients at risk for SE and prolonged seizures are often limited and may have major side effects. Vagal nerve stimulation (VNS) may be an effective treatment to shorten prolonged seizures and prevent SE recurrence. Here, we aim to evaluate SE episodes before and after VNS implantation.


Methods: We reviewed the electronic medical records (EMR) of patients aged 1 month to 21 years old admitted to Boston Children’s Hospital neurology floors between 01/2013 and 04/2024 with ICD 10 codes for epilepsy and seizures (G40*), unspecified convulsion (R56.9) and VNS implantation (X0HQ3R8/Z96.82). Clinical data from the first neurology consultation to the last follow-up visit was manually extracted from the EMR. We evaluated SE occurrence, SE duration, seizure frequency and severity, and number of anti-seizure medications (ASMs) before and after VNS implantation.


Results: We identified 10 patients [median age: 7.5 years (4-16); 50% female] with VNS and SE history prior to VNS implantation. Median (range) duration from the first neurology consultation before VNS implantation was 5.2 years (0.3-15.2) and after implantation was 5.8 years (1.2-16.4). Two patients had Lennox-Gastaut syndrome, one had Dravet syndrome, and one had infantile epileptic spasms syndrome. Of 10 patients, 7 had convulsive SE, including 1 with febrile infection-related epilepsy syndrome (FIRES), and 3 patients had non-convulsive SE.

Following VNS implantation, 5 out of 10 patients (50%) had no further SE episodes. Prior to VNS, patients experienced a median (range) of 4 SE episodes (1-10) with median SE frequency of 0.8 episode /year (0-3) and after implantation, patients had a median (range) of 1 SE episode (0-2) with median SE frequency of 0.06 SE episodes/year (0-2). Of the 5 patients with SE recurrence, SE frequency decreased in 3 patients, increased in 1, and had no change in 1, and the median SE duration decreased from 31 min (9-1440) to 8 min (6-33). Two patients underwent VNS implantation for the acute treatment of ongoing super refractory SE: 1 patient became seizure-free, and the patient with FIRES had increased SE frequency from 1 to 2 SE episodes/year.

Prior to VNS implantation, the median weekly seizure frequency was 17.5 seizures/week (0.2-700); after VNS implantation, the median weekly seizure frequency was 3.5 seizures/week (0-49) with 20% of patients becoming seizure-free. At the time of VNS implantation, 3 patients (30%) received >4 ASMs, 3 (30%) received 4 ASMs, 3 (30%) received 3 ASMs, and 1 patient (10%) received 2 ASMs with a median of 4 ASMs (2-8). One year following VNS implantation, patients were on a median of 3.5 ASMs (1-8) with a decrease in number of ASMs in 50% of patients and no change in the remaining 50%.


Conclusions: VNS is a viable treatment option in selected pediatric patients with a history of SE and may lead to reduced SE recurrence and duration, as well as reduced seizure frequency and number of ASMs.

Funding: The Epilepsy Research Fund supported this study.