Wernicke encephalopathy in a lung cancer patient during treatment with nivolumab.

OBJECTIVE: Wernicke encephalopathy (WE) is a neuropsychiatric disorder caused by thiamine deficiency. It is recognized in various stages of the cancer trajectory but has not previously been recognized during nivolumab treatment. METHOD: From a series of WE patients with cancer, we report a lung cancer patient who developed WE during treatment with nivolumab. RESULT: A 78-year-old woman with lung cancer was referred to our psycho-oncology clinic because of depressed mood. Psychiatric examination revealed disorientation to time, date, and place, which had not been recognized 1 month previously. Her symptoms fulfilled the diagnostic criteria for delirium. No laboratory findings or drugs explaining her delirium were identified. WE was suspected as she experienced a loss of appetite lasting 4 weeks. This diagnosis was supported by abnormal serum thiamine and the disappearance of delirium after intravenous thiamine administration. SIGNIFICANCE OF RESULTS: We found WE in an advanced lung cancer patient receiving treatment with nivolumab. Further study revealed the association between nivolumab and thiamine deficiency. Oncologists should consider thiamine deficiency when a patient experiences a loss of appetite of more than 2 weeks regardless of the presence or absence of delirium.