Acute confusional state
Key points
- Delirium is a condition of severe confusion and rapid changes in brain function.
- Acute confusional states most often result from physical or mental illness and are usually temporary and reversible.
- Delirium involves a rapid alternation between mental states (for example, from lethargy to agitation and back to lethargy), with attention disruption, disorganized thinking, disorientation, changes in sensation and perception, and other symptoms.
- Acute disorders that cause delirium may co-exist with chronic disorders that cause dementia.
Alternative names
Delirium; Acute brain syndrome
Definition
Delirium is a condition of severe confusion and rapid changes in brain function. It is usually caused by a treatable physical or mental illness.
Causes, incidence, and risk factors
Acute confusional states most often result from physical or mental illness and are usually temporary and reversible. Disorders that cause delirium are numerous and varied. They may include conditions that deprive the brain of oxygen or other substances.
Delirium may be caused by diseases of body systems other than the brain, by poisons, by fluid/electrolyte or acid/base disturbances, and by other serious, acute conditions. Infections such as urinary tract infections or pneumonia may trigger delirium in individuals with pre-existing brain damage (prior strokes, dementia).
Patients with more severe pre-existing brain injury are more likely to develop delirium from additional illness.
Symptoms
Delirium involves a rapid alternation between mental states (for example, from lethargy to agitation and back to lethargy), with attention disruption, disorganized thinking, disorientation, changes in sensation and perception, and other symptoms.
- attention disturbance (disrupted or wandering attention)
o inability to maintain goal directed, purposeful thinking or behavior
o inability to concentrate - disorganized thinking, evidenced by
o incoherent speech
o inability to stop speech patterns or behaviors - disorientation to time or place
- changes in sensation and perception (increases the disorientation)
o may precipitate illusions or hallucinations - altered level of consciousness or awareness
- altered sleep patterns, drowsiness
- alertness may vary, usually more alert in the morning, less alert at night (see drowsiness)
- decrease in short-term memory and recall
o unable to recall events since onset of delirium (anterograde amnesia)
o unable to recall past events (retrograde amnesia) - changes in motor activities, movement (for example, may be lethargic or slow moving)
- movements triggered by changes in the nervous system (psychomotor restlessness)
- emotional or personality changes
o anxiety
o angero apathyo depressiono euphoriao irritability
Written and revised by
Gerald Hurowitz, M.D.
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