Nystagmus-based approach to vertebrobasilar stroke presenting as vertigo without initial neurologic signs.

Background: We aimed to investigate the clinical courses and common nystagmus of isolated vertigo patients with vertebrobasilar stroke.

Methods: The patients who presented with isolated acute spontaneous vertigo with spontaneous nystagmus (acute vestibular syndrome) at the Emergency Department were retrospectively analyzed. They were referred to the Otolaryngology Department due to the absence of neurologic signs or even of imaging abnormalities after the initial examination at the Emergency Department. Various clinical features, including presenting symptoms, delayed neurologic signs, the site of infarction, and videonystagmographic (VNG) findings were analyzed.

Results: Of the 468 cases of acute vestibular syndrome, 23 (4.9%) cases of radiologically proven vertebrobasilar stroke were identified. Of the 23 patients, 17 (74%) showed aggravation of vertigo or delayed neurologic signs during the admission. In the analysis of VNG, 11 (48%) cases of direction-changing gaze-evoked nystagmus, 7 (30%) cases of fixation failure in the caloric test, 6 (27%) cases of periodic alternating nystagmus, and 4 (17%) cases of atypical head-shaking nystagmus were presented. Stroke occurred in the cerebellum (n=18, 78%), medulla (n=4, 17%), and pons (n=1, 4%).

Conclusion: In the early stage of vertebrobasilar stroke, an accurate diagnosis was difficult in the Emergency Department even though a radiologic study was performed, but various VNG abnormalities and delayed neurologic signs could help to diagnose whether the origin is central or not.