Delirium

This article is about the mental state. For the graphic novel character, see Delirium (Sandman). For the band, see Delerium. For an album by Polish punk rock band Sedes, see Delirium (Sedes album)

Delirium can also refer to a popular acrobatical performance, Delirium and can also refer to a song in In The Groove, a (Music video game).

Delirium is a medical term used to describe an acute decline in attention and cognition. Delirium is probably the single most common acute disorder affecting adults in general hospitals. It affects 10-20% of all adults in hospital, and 30-40% of older patients.

There are several definitions (including those in the DSM-IV and ICD-10). However, all include some core features.

The core features are:

disturbance of consciousness (that is, reduced clarity of awareness of the environment, with reduced ability to focus, sustain, or shift attention)
change in cognition (e.g., memory impairment) or a perceptual disturbance
onset of hours to days, and tendency to fluctuate.

Common features include:

intrusive abnormalities of awareness and affect, such as hallucinations or inappropriate emotional states.

Delirium should be distinguished from psychosis, in which consciousness and cognition may not be impaired, and dementia which describes an acquired intellectual impairment usually resulting from a degenerative brain disease.

Delirium may be caused by severe physical or mental illness. Fever, poisons (including toxic drug reactions), brain injury, surgery, severe lack of food or water, drug and severe alcohol withdrawal are all known to cause delirium.

It is also referred to as 'acute confusional state' or 'acute brain syndrome'.

Confusion and disorientation

Confusion may occur in delirium, where the sufferer loses the capacity for clear and coherent thought. It may be apparent in disorganised or incoherent speech, the inability to concentrate or a lack of goal directed thinking.

Disorientation describes the loss of awareness of the surroundings, environment and context in which the person exists. Disorientation may occur in time (not knowing what time of day, day of week, month, season or year it is), place (not knowing where you are) or person (not knowing who you are).

Cognitive impairments

Impairments to cognition may include reduction in the function of short or long term memory, attention or problem solving.

Abnormalities of awareness and affect

Hallucinations (perceived sensory experience with the lack of an external source) or distortions of reality may occur in delirium. Commonly these are visual distortions, and can take the form of masses of small crawling creatures (particularly common in delirium tremens, caused by severe alcohol withdrawal) or distortions in size or intensity of the surrounding environment.

Strange beliefs may also be held during a delirious state, but these are not considered delusions in the clinical sense as they are considered too short lived. Interestingly, in some cases sufferers may be left with false or delusional memories after delirium, basing their memories on the confused thinking or sensory distortion which occurred.

Abnormalities of affect include any distortions to perceived or communicated emotional states. Emotional states may also fluctuate, so a person may rapidly change between, for example, terror, sadness and jocularity.

Duration

The duration of delirium is typically affected by the underlying cause. If caused by a fever, the delirious state should subside as the severity of the fever subsides. However, it has long been suspected that in some cases delirium persists for months and that it may even be associated with permanent decrements in cognitive function. Barrough said in 1583 that if delirium resolves, it may be followed by a "loss of memory and reasoning power". Recent studies bear this out, with cognitively normal patients who suffer an episode of delirium carrying an increased risk of dementia in the years that follow.

Accounts of delirium

Sims (1995, p.31) points out a "superb detailed and lengthy description" of delirium in The Stroller's Tale from Charles Dickens' The Pickwick Papers.

Confusion and disorientation

Cognitive impairments

Abnormalities of awareness and affect

Duration

Accounts of delirium

Further reading