Daniel R. Gold, D.O. Departments of Neurology, Ophthalmology, Neurosurgery, Otolaryngology - Head & Neck Surgery, The Johns Hopkins School of Medicine; Tzu-Pu Chang, MD, Department of Neurology/Neuro-Medical Scientific Center, Taichung Tzu Chi Hospital, Tzu Chi University
This is a 50-year-old who experienced the abrupt onset of prolonged vertigo following chiropractic therapy 2 months prior. Initial work-up included an MRI and MR angiogram - MR-diffusion weighted imaging showed an acute left lateral medullary stroke and left vertebral artery occlusion, which was thought to be related to a dissection. ; The examination seen here was performed 2 months following his stroke, and there was no spontaneous nystagmus with fixation. When fixation was removed with video infrared goggles, right-beating (with a slight torsional component, top poles beating towards the right ear) nystagmus was apparent. Head impulse testing in the planes of the horizontal canals was normal, which is a "central" sign in patients presenting with acute vertigo and spontaneous nystagmus. He also had a skew deviation with a left (ipsilesional) hypotropia. When the utricle-ocular motor fibers are affected caudal to their decussation as in a lateral medullary stroke, the hypotropic eye will be ipsilesional as in this case. Therefore, the HINTS (Head Impulse, Nystagmus, Test of Skew) exam was consistent with a central localization. ; Additionally, there was saccadic dysmetria, with hypermetric saccades to the (ipsilesional) left side and hypometric saccades to the (contralesional) right side. Although not shown here, there was also leftward ocular lateropulsion, a finding which is usually seen ipsilateral to hypermetric saccades. This is a typical finding in the Wallenberg syndrome, given involvement of the inferior cerebellar peduncle and the climbing fibers that course through it on their way to the ipsilateral dorsal vermis (see normal saccadic pathway https://collections.lib.utah.edu/details?id=1260093, and what happens to saccades with lateral medullary injury https://collections.lib.utah.edu/details?id=1260094).
Spencer S. Eccles Health Sciences Library, University of Utah