LAUSR

Vagal nerve stimulator (VNS) can be an effective treatment for refractory epilepsy but can lead to sleep related disordered breathing in the form of obstructive and central sleep apnea. We describe a pediatric case with VNS developing severe obstructive sleep apnea (OSA) and the course of management. A 10-year-old boy with history of cerebral palsy, medically intractable epilepsy secondary to Lennox-Gastaut syndrome, and noted improvement in seizure frequency with VNS placement, presented to the pediatric sleep clinic with concern for sleep disordered breathing in the setting of snoring and witnessed gasping at night. The polysomnogram (PSG) showed severe OSA with apnea/hypopnea index (AHI) of 21.8 events/hour and associated hypoxemia. He subsequently underwent adenotonsillectomy. Post procedural PSG demonstrated persistent severe OSA. The obstructive events had rhythmicity temporally coincident with the VNS cycling. Subsequent PSG, after turning VNS off, showed a reduction in AHI to 11 events/hour without hypoxemia. Positive airway pressure (PAP) was initiated during this PSG, however titration was rendered unsuccessful due to VNS activation. A final titration PSG was performed with optimal resolution of OSA with VNS turned off. Since the patient did not have nocturnal seizures, it was recommended to turn the VNS off at nighttime with CPAP use. Patient was noted to have less sleep disruptions at night and more alertness during the day. This case poses a challenging situation where patient’s epilepsy responded to VNS but the device contributed to OSA and affected PAP titration. One strategy to improve OSA in such cases is to change VNS parameters at the risk of changing stimulation settings effective for seizure control. Turning VNS off during sleep provided a simpler solution while ensuring effective treatment. Thus, clinicians should be vigilant about concomitant OSA treatment in the setting of vagal nerve stimulation, which can improve quality of life.