Abstract
Introduction
Vagus nerve stimulation (VNS) is an adjunct treatment for seizures refractory to medications. VNS in children with epilepsy can reduce seizures by up to 90%. VNS settings include stimulation on-time, off-time, frequency and output current. Complications of VNS include sleep-disordered breathing due to laryngopharyngeal dysfunction, which can also cause voice alteration, hoarseness, and cough. Both obstructive apneas (more common) and central apneas can be seen in those patients who have VNS-induced sleep-disordered breathing.
Report of case(s)
A 14-year-old male with Lennox-Gastaut syndrome treated with multiple antiepileptic drugs and VNS was admitted to the PICU with worsening seizures. He developed acute respiratory failure due to status epilepticus, requiring intubation. After extubation, he was observed to have repetitive respiratory obstruction at regular intervals, occurring throughout the day and night, and associated with mild oxygen desaturations. Polysomnography showed cyclical obstructive respiratory events lasting 30 seconds followed by approximately 2-minute intervals of regular breathing. Interrogation of his VNS device revealed the following settings: output current of 1.75 mA, 30 seconds on, and 1.8 minutes off. CPAP therapy improved his oxygen saturations, but he continued to clinically exhibit the repetitive obstructive apneas even on positive pressure. However, after his VNS device settings were decreased, repeat polysomnography showed resolution of his obstructive breathing.
Conclusion
This case report demonstrates pediatric VNS-induced obstructive sleep apnea. Activation of the vagus nerve can cause laryngopharyngeal dysfunction, including laryngospasm and vocal cord dysfunction, with subsequent upper airway obstruction, causing obstructive apneas or hypopneas. Treatment options for pediatric VNS-induced OSA include CPAP, decreasing the VNS settings and adenotonsillectomy.
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