About Delirium

What is delirium?

Delirium (or acute confusion) is a sudden change in mental status, or sudden confusion, which develops over hours or days. It is different from dementia, such as Alzheimer’s disease, which is a chronic state that progresses over time. In general, delirium is a short-term condition.  Delirium is sometimes called “acute brain failure” because of its sudden and dramatic onset. The exact pathogenesis of delirium remains unclear.

What are the features of delirium?

Delirium makes paying attention or focusing difficult, and sometimes affects the ability to maintain awareness of one's surroundings. Some people hallucinate or become paranoid because it becomes difficult to interpret their environment. Other symptoms may include rambling speech and jumbled thoughts. These symptoms tend to come and go during the course of the day. Confusion regarding day-to-day events, daily routines, and the roles of familiar people is common. Changes in personality can occur. Some persons become quiet and withdrawn while others become agitated or hyperactive. Normal patterns of sleeping and eating are often disrupted.

How do you recognize delirium?

  • The Confusion Assessment Method (CAM) is the most widely used, standard tool for identification of delirium
  • The four major CAM criteria are:
    1. acute onset fluctuating and course – and –
    2. inattention – and either –
    3. disorganized thinking – or –
    4. altered level of consciousness
  • The CAM is rated by a clinical or trained lay interviewer on the basis of an interview with the patient that includes at least a brief cognitive assessment (i.e., the SPMSQ or Modified Mini-Cog Test).

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Ref: The Confusion Assessment Method, ©2003, Hospital Elder Life Program. Inouye SK, et. al. Ann Intern Med. 1990, 113: 941-8