Acute delirium in a critically ill patient may be a wolf in sheep's clothing.

Acute delirium is a commonly encountered problem in the intensive care unit (ICU), which has a myriad of causes and contributes to poor outcomes. We present the case of an alcoholic critically ill patient who developed prolonged acute ICU delirium wrongly diagnosed as sedation and alcohol withdrawal. Protracted vomiting, swallowing disorders and continuous aspirations prevented him from enteral feeding and discontinuation of mechanical ventilation. After several days, it became clear that the patient had been misdiagnosed. Fortunately, nystagmus and ophthalmoplegia then allowed the recognition of Wernicke's encephalopathy, confirmed by cerebral MRIs. After thiamine supplementation, his state improved but he was discharged only on day 32. Wernicke's encephalopathy is an acute reversible neuropsychiatric emergency, which is falsely considered as uncommon, and is largely misdiagnosed, especially in critically ill patients. Thiamine should be systematically given to all critically ill alcoholic patients, especially those with protracted vomiting.