An 18-year-old critically ill boy was receiving parenteral nutrition during a complicated hospitalization. MRI was obtained after he developed a decreased level of alertness and twitching in his right arm. Axial fluid-attenuated inversion recovery (FLAIR) images showed hyperintense signal involving the cortex of the posterior left frontal lobe, posteromedial thalami, tectal plate, and mammillary bodies. Diffusion-weighted images showed corresponding diffusion restriction (not shown). Findings were consistent with nonalcoholic Wernicke encephalopathy. Laboratory evaluation confirmed thiamine deficiency, and he underwent intravenous thiamine repletion; his mental status changes and right upper extremity twitching subsequently resolved.
Wernicke encephalopathy is caused by thiamine (vitamin B1) deficiency. The classic triad of Wernicke encephalopathy consists of altered consciousness, ophthalmoplegia, and ataxia. Typical areas of involvement include the mammillary bodies, periaqueductal gray matter, tectal plate, and medial thalami. Atypical areas include the cerebellum, caudate nuclei, red nuclei, splenium, and cerebral cortex.1 MR signal abnormalities in these areas show increased T2 and FLAIR signal, often with diffusion restriction.
In adults, Wernicke encephalopathy is commonly associated with chronic alcoholism. In nonalcoholic patients, numerous causes of nutritional deficiency of thiamine can lead to Wernicke encephalopathy in both pediatric and adult patients, including parenteral nutrition, hyperemesis from pregnancy or chemotherapy, eating disorders, and poor nutrition secondary to poverty or neglect.2 Without treatment, Wernicke encephalopathy can lead to devastating neurologic impairment or death. After treatment with intravenous repletion of thiamine, the imaging findings and neurologic symptoms of Wernicke encephalopathy are often reversible.1,2
At the Viewbox: Wernicke Encephalopathy. J Am Osteopath Coll Radiol.