Transcutaneous auricular vagus nerve stimulation in adult abdominal epilepsy associated with ketosis-prone diabetes: A case report

Rationale: Abdominal epilepsy (AE) is a rare form of focal epilepsy that may present with recurrent paroxysmal gastrointestinal symptoms and can be difficult to distinguish from metabolic or gastrointestinal disorders. Ketosis-prone diabetes (KPD) may further complicate diagnosis because diabetic ketoacidosis, hypoglycemia, and glycemic instability can produce overlapping abdominal and neurobehavioral manifestations. Patient concerns: A 35-year-old Chinese man with poorly controlled type 2 diabetes mellitus and recurrent ketosis presented with severe abdominal pain and vomiting during an episode of diabetic ketoacidosis. He had a 2-year history of recurrent stereotyped periumbilical abdominal pain. Diagnoses: After unrevealing gastrointestinal, vascular, toxic, and metabolic evaluation, ictal electroencephalography (EEG) showed left temporal rhythmic sharp-slow-wave complexes with ipsilateral spread. The patient was diagnosed with ketosis-prone diabetes and EEG-supported AE, later considered drug-resistant. Interventions: Management included metabolic stabilization, oxcarbazepine–lamotrigine antiseizure therapy, and subsequent adjunctive transcutaneous auricular vagus nerve stimulation (taVNS) for persistent stereotyped abdominal episodes. Outcomes: During follow-up after adjunctive taVNS, the patient reported fewer episodes of abdominal pain. Diabetic ketoacidosis did not recur, and no device-related adverse events were observed. Because improvement occurred alongside continued antiseizure therapy and metabolic stabilization, causality cannot be inferred from this single-case observation. Lessons: In diabetic patients with recurrent unexplained abdominal pain, AE should be considered when episodes are stereotyped, abrupt, or accompanied by orofacial automatisms, altered awareness, autonomic instability, or a mismatch between symptom severity and abdominal findings. Early EEG may help reduce diagnostic delay, whereas adjunctive taVNS should be viewed as exploratory.