Primary abdominal manifestations of vagus nerve stimulation: illustrative case.

Background: Vagus nerve stimulation (VNS) is a neuromodulation option for seizure control in intractable epilepsy. Commonly reported side effects of VNS include manifestations of vagus nerve dysfunction, such as cough, hoarseness, and neck pain. While some patients experience transient nausea and vomiting, more significant gastrointestinal (GI) symptoms have not yet been described in the literature.

Observations: The patient is a 13-year-old female with type 4 early infantile epileptic encephalopathy who underwent placement of a left-sided VNS system for treatment of medically refractory epilepsy. After initiation of VNS, she developed abdominal pain, worsened constipation, decreased oral intake progressing to complete oral aversion, and urinary retention. The VNS device was turned off after 6 months, leading to resolution of the listed symptoms.

Lessons: Review of this patient's symptoms highlights two ways that VNS may affect vagal signaling: disruption of pain modulation pathways and aberrant stimulation leading to GI dysmotility. Prior studies of the vagus nerve topography reveal heterogeneity in the layout of fascicles, which are unaccounted for with the current surgical technique. Recognition of the potential association of VNS with this uncommon collection of symptoms is important for surgeons offering this treatment. https://thejns.org/doi/10.3171/CASE25117.