A case of new cognitive changes in a patient with seronegative paraneoplastic limbic encephalitis: encephalitis relapse or Wernicke's encephalopathy?

Wernicke's encephalopathy (WE) and paraneoplastic limbic encephalitis (PLE) can both present with acute-to-subacute memory impairment and cognitive dysfunction. Both can lead to significant morbidity and mortality without rapid identification and treatment. Often patients with WE may not have the typical clinical triad of ophthalmoplegia, gait ataxia, and altered mental status. Furthermore, both WE and PLE may share similar MRI findings. Here, we present a case of a patient with a history of seronegative PLE presenting with acute-to-subacute cognitive changes and gait imbalance. Initially, it was felt to be a relapse of PLE but upon further history and testing may potentially have represented WE in the setting of a recent dietary change.