A 45-year-old male presented with focal onset seizures with dyscognitive symptoms and focal to bilateral convulsions during his first visit to our institution in August 2013. Diagnosed with epilepsy at the age of 6 years, he had been on several antiseizure agents for more than 20 years, with levetiracetam, rufinamide, valproic acid, and clonazepam as his recent medications. Despite his medical management, he experienced seizures occurring in clusters, with a maximum of up to 25 per day. His semiology included motionless staring followed by body shaking lasting for 30 s without any preceding aura. The postictal period lasted for hours during which he remained groggy and had mood changes. His baseline mental functioning included intellectual disability, non-verbal status with limited sign language skills, stable mood with no behavioral outbursts, obsession for American football and normal sleep-wake cycle. He received 24-hour care from well-educated and engaged parents, with reliable adherence to medication. His past medical history also included hypothyroidism, pulmonary valve anomaly, deafness, Hodgkin lymphoma, bladder carcinoma with urostomy, and right kidney transplant. The patient's most recent EEG (electroencephalogram) (performed in October 2010 while the patient was on antiseizure medications) was within normal limits. We found no significant, pertinent abnormal findings on physical examination during his first visit. His follow-up laboratory values were within normal limits, including the anti-seizure drug levels (levetricetam 39.9 mcg/ml) and TSH (2.2 mIU/L). His brain magnetic resonance imaging was abnormal, showing mild to moderate age-advanced cerebral and cerebellar atrophy, most likely to be an insult from hypoxic-ischemic encephalopathy at birth. During the patient's follow-up period after his initial visit, he failed adjustments of levetiracetam (increased to 1500 mg BID). Hence, we decided to proceed with VNS implantation for his drug-resistant epilepsy.
VNS device implantation (Model Demipulse 103, Liva Nova, Houston, TX) was performed on October 21, 2013. The electrodes were placed over the left vagus nerve following standard procedure. Two weeks later, stimulation was initiated with the following parameters: amplitude of 0.25 mA, frequency of 30 Hz, and pulse width of 500 mus with a stimulation period of 30 s followed by a 5-minute off-time. The patient's baseline height, weight, and basal metabolic index were 4 ft. 6 in, 47.6 kg, and 25.3 kg/m2, respectively. The weight measured was 22% greater than the ideal body weight (39 kg). On follow-up, the patient's parents reported improvement in seizure frequency with only 4 episodes occurring during the 3-month period and improved quality of life with no side effects from VNS such as a change in his voice or neck pain. Follow-up repeat EEG was also normal. Hence, VNS was continued with medication adjustments, including a decrease in the dose of levetiracetam to 1000 mg BID and initiation of ezogabine at 100 mg TID, after ophthalmology screening for pigment retinopathy. In addition, he was continued on his previous regimen of rufinamide, valproic acid, and clonazepam. At his follow-up visit in December 2013, the patient had complaints of throat irritation and poor oral intake. His weight was 45.8 kg, and he was advised to take Cepacol lozenges twice daily for the next 3 months. In March 2014, his weight was 41.7 kg. Because of his significant weight loss, we adjusted the stimulation parameters to a reduced setting as shown in Fig. 1. During the next 6 months, the patient's appetite remained suppressed, and VNS was eventually discontinued in August 2014. Anti-seizure drug levels were within acceptable limits (levetricetam: 73.8 mcg/ml; valporic acid: 43.1 mcg/ml). However, during his visit in December 2014, the patient reported 4 seizures, so VNS was restarted in January 2015. By October 2015, the patient's seizure frequency improved, and stimulation parameters were increased. However, this time the patient's weight and appetite improved, and he gained a total of 3.6 kg. By April 2016 his body weight exceeded his baseline weight at the time of implantation of the VNS device. Furthermore, his seizure burden continued to improve. He remained seizure free from April 2016 till his recent visit in January 2017. No changes to his antiseizure medications were made from November 2013 till January 2017.