'Iatrogenic' Wernicke's encephalopathy in Japan.

'Iatrogenic' Wernicke's encephalopathy has appeared to occur more frequently in Japan, probably induced by the change of our Japanese national health insurance policy in 1992. We report 4 nonalcoholic patients with such Wernicke's encephalopathy, which occurred during the early postoperative oral food intake period following intravenous nutrition without vitamin supplements. We analyzed the medical records of 4 patients, 3 men and 1 woman, aged between 55 and 71 years, who were admitted to our hospital between 1992 and 1995. Three patients underwent gastrointestinal surgery and 1 suffered chronic pyothorax. We diagnosed our patients as having Wernicke's encephalopathy based on typical neurological abnormalities, in addition to typical cranial magnetic resonance image findings, low serum vitamin B(1) levels, or both. Although all of the patients were treated with vitamin B(1) and showed some improvement, 1 patient developed Korsakoff syndrome, 2 made incomplete neurological recovery, and 1 died. We speculated that the body vitamin B(1) stores had been decreasing in our patients who did not receive any vitamin supplements during intravenous hyperalimentation or hydration. Subsequent administration of high calorie and high carbohydrate oral diets increased the demand for vitamin B(1), further depleting the vitamin stores, thereby causing 'iatrogenic' Wernicke's encephalopathy. The change of our national health insurance policy in 1992 discouraged the routine administration of vitamins, probably causing Wernicke's encephalopathy in our patients.