Wernicke's Encephalopathy Masquerading as an Acute Cerebellar Stroke.

Wernicke's encephalopathy (WE) is an acute neurological emergency resulting from severe thiamine deficiency, frequently mimicking acute cerebellar stroke due to its abrupt onset and neurological manifestations. Early recognition is crucial to prevent severe complications. Here, we report the case of a 52-year-old male with alcohol use disorder who presented with acute dizziness, vomiting, and gait instability. Neurological examination revealed left facial droop, dysarthria, and an ataxic gait with a positive Romberg sign. Given the presentation, an acute stroke was initially suspected (National Institute of Health Stroke Scale score: 4), but computed tomography and computed tomography angiography excluded vascular pathology. Magnetic resonance imaging findings demonstrated bilateral thalamic and periaqueductal hyperintensities, confirming WE. Intravenous thiamine administration led to rapid clinical improvement, and the patient was discharged on oral thiamine in a stable condition. WE remains underdiagnosed due to its variable presentation. While nystagmus is a hallmark sign, ataxia is also significant. Given its reversibility, clinicians should maintain a high index of suspicion, especially in patients with alcohol use disorder presenting with cerebellar signs. Prompt thiamine administration can prevent severe morbidity and mortality.