Isolated mammillary body involvement on MRI in Wernicke's encephalopathy

A 48-year-old woman, with a remote history of gastric-banding as well as recent-onset post-prandial vomiting and excessive wine-drinking, was admitted with progressively-worsening gait incoordination. She showed gaze-evoked nystagmus and gait ataxia. Brain MRI revealed conspicuous, isolated, symmetrical T2/FLAIR-hyperintensities and gadolinium-enhancement of the mammillary bodies. Serum thiamine and folate were low. Following thiamine and folate replacement therapy, her ataxia resolved. Given the rising number of bariatric procedures, we discuss the importance of recognizing thiamine-deficiency in these patients. Additionally, while isolated involvement of the mammillary bodies is a rare finding in this disorder, we highlight radiologic changes that neurologists should recognize.