Wernicke encephalopathy (WE) is an acute neuropsychiatric disorder caused by thiamine deficiency. The classical triad of symptoms for WE include mental status changes, ataxia, and ophthalmoplegia. In contrast, more uncommon symptoms include hallucinations. Known risk factors include alcoholism, malignancies, and chronic kidney disease, particularly hemodialysis. However, WE in nonalcoholic adults is often overlooked.

We report a WE patient with lung cancer undergoing hemodialysis who presented with the uncommon symptom of active hallucinations, which were improved by thiamine replacement therapy, despite a borderline whole blood thiamine concentration.

An 81-year-old woman with lung cancer and undergoing hemodialysis was referred to our psycho-oncology department for active hallucinations that appeared suddenly 24 days earlier. She had been diagnosed with lung cancer 6 months earlier and was undergoing chemotherapy and radiotherapy. She had no alcohol dependence or anorexia before or after admission. Physical examination revealed active visual hallucinations and delirium. On suspicion of WE, intravenous thiamine was administered. One day after administration, the hallucinations and delirium improved. Her whole blood thiamine concentration was borderline (24 ng/ml).

WE might be a cause of active visual hallucinations as they disappeared on thiamine administration alone. We need to be aware of risk factors such as malignancies and hemodialysis, and it is important not to overlook WE.