ObjectiveTo explore the clinical features and prognosis of patients with neuromyelitis optica spectrum disorder (NMOSD) initially presenting with acute brainstem symptoms. MethodsThe clinical data of NMOSD patients admitted to two medical centers were collected. The clinical characteristics, laboratory data, neuroimaging features and prognoses of patients with NMOSD with acute brainstem manifestations as initial symptoms (NMOSD-BSMIS) were analyzed. The clinical features and prognosis of patients with NMOSD-BSMIS and patients with NMOSD with other manifestations as initial symptoms (NMOSD-OMIS) were compared. ResultsFifty-two patients (18.37 %, 52/283) initially presented with acute brainstem symptoms. Intractable nausea, vomiting or hiccups, diplopia, vertigo, headache, and facial hypoesthesia were the initial symptoms in most of the patients. The percentage of patients who were positive for serum aquaporin 4 (AQP4)-IgG antibodies was 81.63 % (40/49). MRI revealed that the lesions were usually located in the postrema, dorsal medulla oblongata, pons and other areas around the fourth ventricle. The early-stage misdiagnosis rate was 46.15 %. Compared with those in the non-misdiagnosed group, the age of onset of patients in the NMOSD-BSMIS group was older, and the proportion of patients admitted to the neurology department as the first department was lower in the misdiagnosed group. The annual relapse rate of patients who underwent NMOSD-BSMIS was significantly greater than that of patients who underwent NMOSD-OMIS (P < 0.01). ConclusionsNMOSD patients can initially present with different brainstem symptoms. The early misdiagnosis rate of NMOSD-BSMIS is high. Moreover, if patients are older or initially admitted to nonneurological departments, they are more likely to be misdiagnosed. Moreover, the annual recurrence rate of NMOSD-BSMIS is greater in the early stage.