[A case of neuromyelitis optica spectrum disorder with persistent nausea and repeated syncope].

A 22-year-old woman was admitted to our hospital with persistent nausea and no apparent cause. There was no preceding infection. The patient lost consciousness for several seconds. Based on an electrocardiographic diagnosis of paroxysmal sinus arrest (PSA), a temporary pacemaker was implanted. She did not develop syncope, but vertigo, nystagmus, diplopia, and limb paresthesia were observed. Brain MRI revealed a high-intensity lesion in the dorsal medulla on FLAIR images. As the serum anti-aquaporin 4 (AQP4) antibody was positive, the patient was diagnosed with neuromyelitis optica spectrum disorder (NMOSD). After she received steroid pulse therapy (methylprednisolone at 1,000 mg/day for three days) twice, her symptoms markedly improved. In this patient, PSA was considered to be a symptom of area postrema syndrome of NMOSD. Therefore, NMOSD should be considered as a possible cause of PSA.