Wernicke Encephalopathy During Neoadjuvant Folinic Acid, Fluorouracil, and Oxaliplatin (FOLFOX) Therapy for Rectal Adenocarcinoma: A Case Report and Review of Diagnostic Challenges.

Wernicke encephalopathy (WE) is an acute neurologic disorder caused by thiamine deficiency. A 55-year-old Caucasian female patient undergoing treatment with neoadjuvant folinic acid, fluorouracil, and oxaliplatin for locally advanced rectal adenocarcinoma presented with intractable nausea and vomiting resulting in clinically significant weight loss and malnutrition. Oculomotor dysfunction and gait disturbance were noted, and empiric treatment for WE was initiated with high-dose intravenous thiamine. A contrast-enhanced MRI brain was obtained and showed no acute abnormality. Diagnosis was confirmed by therapeutic response to thiamine in conjunction with a low serum thiamine level.