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A 70-year-old man lives with his daughter. She is awakened one night and finds him wandering in the kitchen with the pots in disarray. He cannot explain clearly what he is doing, and she is worried because this is a dramatic change for him. She takes him to see you for immediate evaluation.

  • What additional questions can you ask to determine the cause of his change in mental status?
  • What are the possible causes for the quick onset of confusion?
  • What life-threatening conditions need to be considered immediately?
  • How can you use the patient history to determine whether this is occurring in the setting of previously normal cognitive function versus underlying cognitive impairment?

Confusion is an impairment in attention and is characterized by an inability to maintain a coherent stream of thought or action. An "acute confusional state" is a prolonged period of confusion and is synonymous with "delirium." An acute confusional state is usually of abrupt onset, and the mental status fluctuates from alert and hypervigilant to obtunded. An altered level of consciousness is common and can be the predecessor of stupor and coma if the underlying cause is not found and reversed. Confusion presents a unique challenge in acquiring a direct patient history because the patient is inattentive and distractible. In a confusional state, the organ system that is required to report on symptoms (the central nervous system [CNS]) is itself dysfunctional. For that reason, most of the historical information must be acquired from caregivers and family members. Although this poses an extra level of challenge in acquiring accurate historical information, the history is often crucial in determining the correct diagnosis.

Dementia is a chronic, progressive loss of cognitive function that impairs day-to-day abilities and predisposes to confusion if the brain is challenged with even a relatively minor toxic or metabolic disturbance. A major diagnostic challenge is to determine whether the altered mental status is due solely to an acute condition or whether an underlying dementia is acting as a predisposing factor.1 The diagnosis of delirium is missed in up to 40% to 60%2 of those affected and is a sign of a worse prognosis with higher hospital readmission rates and 30-day mortality, especially if untreated. Confusion may be seen in up to 20% of elderly patients admitted to hospital, and of those admitted not confused, 25% to 50% will develop an episode of confusion during the admission. Regardless of cause, delirium confers a worse prognosis with higher hospital readmission rates and 30-day mortality, especially if untreated.3 The causes of delirium differ greatly depending on the setting (ie, hospital versus nonhospital setting).

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Delirium/acute confusional state/diffuse encephalopathySynonymous terms for an acute impairment in attention or disorganized thinking, with a fluctuating course and altered level of consciousness.
DementiaChronic progressive degenerative condition affecting memory, behavior, and cognition.
AttentionThe ability to focus on specific ...

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