Afebrile delirium is a medical condition characterized by confusion, disorientation, and changes in behavior. There are several synonyms for this condition, including acute confusional state, encephalopathy, and acute brain dysfunction. Other descriptors may include altered mental status, cognitive impairment, and cognitive dysfunction. Regardless of what it is called, afebrile delirium is a serious medical condition that can have a significant impact on a person's quality of life. It is often seen in elderly patients or those suffering from systemic illness, and prompt medical attention is necessary to manage the symptoms and prevent further complications.