RESUMEN
A 43-year-old male presented with elevated serum creatinine for 4 years and developed abdominal pain for 3 days. He started peritoneal dialysis 2 months ago. Dialysis-related peritonitis was ruled out and acute gastroenteritis was diagnosed. The patient was administrated with ertapenem 500 mg/d. An acute mental abnormality developed 3 days later. After excluded organic encephalopathy, ertapenem was discontinued for the suspicion of antibiotic-related encephalopathy. The frequency of peritoneal dialysis was increased to accelerate the clearance of antibiotics. However, the metal abnormality became even more severe. Then a diagnosis of Wernick-Korsakoff syndrome was considered. After the administration of high dose vitamin B1, the mental disorder dramatically relieved. Vitamin B1 30 mg/d is maintained during peritoneal dialysis and the mental disorder does not relapse.