WALLENBERG LATERAL MEDULLARY SYNDROME - CLINICAL-MAGNETIC RESONANCE IMAGING CORRELATIONS

Objective.-To correlate clinical and radiologic findings in patients with lateral medullary infarction. Design.-Case series with ''blinded' evaluation of brain imaging. Setting.-Hospitalized and ambulatory patients at the Neurological Institute of New York (NY). Patients.-Thirty-three consecutive patients with lateral medullary syndrome were evaluated by the Stroke Center between 1983 and 1989. Results.-Ataxia (70%), numbness either of the ipsilateral face or of the contralateral body (64%), vertigo (51%), and dysphagia (51%) were the most frequent symptoms at onset. Eleven patients had ocular symptoms (diplopia or blurred vision). Horner's syndrome was found in 91%, ipsilateral ataxia in 85%, and contralateral hypalgesia in 85%. Nystagmus (61%) and facial weakness (42%) were less frequent. Head computed tomography was abnormal only when a cerebellar infarction was present (three cases). Magnetic resonance imaging, obtained in 22 cases, was normal in two; a lateral medullary infarction alone was present in 12, and a lesion extending beyond the lateral medulla was found in eight. No correlation was noted between facial weakness or ocular symptoms and infarction extending beyond the lateral medullary region. Vertebral artery disease was confirmed by vascular imaging or insonation studies in 73% of patients. Conclusions.-The triad of Horner's syndrome, ipsilateral ataxia, and contralateral hypalgesia will clinically identify patients with lateral medullary infarction. Facial weakness and ocular symptoms are frequent and do not necessarily imply that the infarction extends beyond the lateral medulla. Cerebellar infarcts only infrequently accompany lateral medullary syndrome, suggesting that most of the posterior inferior cerebellar artery territory is spared, despite the high frequency of vertebral artery occlusion.