Isolated Pulvinar/Hockey Stick Sign in Nonalcoholic Wernicke's Encephalopathy.

BACKGROUND Wernicke's encephalopathy (WE), a commonly misdiagnosed and underdiagnosed pathology, presents with altered mental status, ataxia, and ophthalmoplegia. WE is most commonly caused by excessive alcohol use, but also has diverse nonalcoholic etiologies. Here we describe 2 cases of nonalcoholic WE with different etiologies that were initially misdiagnosed due to lack of correlation of magnetic resonance imaging (MRI) findings with clinical information. CASE REPORT Patient A, a 50-year-old woman with recent gastric sleeve surgery, presented with horizontal gaze-evoked nystagmus, ataxia, and altered mental status. MRI fluid-attenuated inversion recovery (FLAIR) revealed isolated bilateral, symmetrical, thalamic hyperintensities, initially diagnosed as variant Creutzfeldt-Jakob disease. A review of imaging and clinical presentation provided an alternate diagnosis of nonalcoholic WE secondary to nutritional deficiency. Intravenous (IV) thiamine improved symptoms with resolution of MRI findings 6 months later. Patient B, a 64-year-old woman, presented with nausea, vomiting, dizziness, altered mental status, and weight loss. MRI FLAIR revealed isolated bilateral, symmetrical, thalamic hyperintensities, initially determined to be ischemia, prompting stroke management. A diagnosis of nonalcoholic WE was suggested, given the patient's low thiamine levels and history of malnutrition, and was confirmed by her excellent therapeutic response to IV thiamine. CONCLUSIONS Nonalcoholic WE remains a challenging diagnosis because of the variable clinical presentation, myriad of underlying etiologies, and lack of standardized diagnostic laboratory tests. A multidisciplinary approach with close collaboration between the radiologist and clinical care team is critical to narrow down the differential and initiate correct management. WE is a reversible disease with catastrophic consequences if it is not recognized and treated promptly.