Presumed pharmacologically induced change from upbeat- to downbeat nystagmus in a patient with Wernicke’s encephalopathy

A case of Wernicke’s encephalopathy due to proven thiamine deficiency suffering from upbeat nystagmus (UN) changing to downbeat nystagmus (DN) after a latency of 1 year is presented. The case was also notable for the finding of positive oligoclonal bands in the CSF. The underlying pathophysiological mechanisms and a possible effect of baclofen treatment are discussed.