A 40-year-old man with a history of alcohol dependence is admitted in Hospital for knee injury. Which of the following is the most common cause of delirium within 3 days postoperatively?

Ans. C. Delirium tremensThe most common cause of delirium in this case is delirium tremens. It is a medical emergency that results in mortality in about 20 percent of patients if left untreated. It occurs within 1 week after the person stops drinking. It usually develops on the third hospital day in a patient admitted for an unrelated condition (e.g., surgery) who has no access to alcohol and stops drinking suddenly. Another less common cause of postoperative delirium is stress, especially in major procedures such as cardiac or transplantation surgery. Pain, pain medications, and infection must also be considered in the postoperative period.