Table of Contents
Overview – Delirium
Delirium is an acute neuropsychiatric syndrome characterised by a sudden onset of fluctuating disturbances in attention, awareness, and cognition. It is typically caused by an underlying medical condition, drug intoxication or withdrawal, or a combination of physiological stressors. Delirium is common in hospitalised and elderly patients and is associated with increased morbidity, mortality, and prolonged hospital stays, making early recognition and prompt management essential.
Definition
Delirium is a transient, reversible condition of global cerebral dysfunction marked by acute changes in cognition and consciousness, particularly attention and awareness, usually in response to an underlying physiological cause.
DSM-5 Diagnostic Criteria
- A) Disturbance in attention (e.g. reduced ability to focus or shift attention) and awareness (reduced orientation to the environment)
- B) Develops acutely (hours to days), fluctuates in severity over the course of a day
- C) Additional cognitive disturbance (e.g. memory deficit, disorientation, language disturbance, visuospatial or perceptual deficits)
- D) Not better explained by another neurocognitive disorder and does not occur in severely reduced arousal states (e.g. coma)
- E) Direct physiological cause from a medical condition, substance intoxication/withdrawal, toxin, or multiple etiologies
Subtypes of Delirium
- Hyperactive: agitation, restlessness, hallucinations, delusions
- Hypoactive: lethargy, sedation, decreased responsiveness (commonly missed)
- Mixed: alternating features of both
Clinical Features
- Disorientation in time/place
- Poor attention and distractibility
- Illusions, hallucinations, and misinterpretations
- Language disturbances: dysarthria, word-finding difficulty
- Emotional lability: anxiety, irritability, fear, apathy
- Psychomotor changes: fidgeting, pulling at lines, or unresponsiveness
- Disturbed sleep-wake cycle, often reversed
Management
1. Identify and Treat the Underlying Cause
- Stop non-essential medications
- Correct fluid, electrolyte, and metabolic abnormalities
- Treat infections or other triggers
- Monitor vitals, glucose, and nutrition
2. Optimise the Environment
- Quiet, well-lit room with natural lighting
- Place clock/calendar in view for reorientation
- Encourage use of glasses/hearing aids
- Family presence to reduce distress
- Consider constant nursing if at risk of harm
- Use verbal reorientation regularly
3. Pharmacological Treatment
- Antipsychotics (low dose, high potency):
- Haloperidol (most evidence)
- Risperidone, Olanzapine (less QTc prolongation), Quetiapine (fewer extrapyramidal side effects), Aripiprazole (may shorten QTc)
- Benzodiazepines ONLY for alcohol or substance withdrawal delirium
- Avoid medications with anticholinergic effects
4. Safety Measures
- Use physical restraints only as a last resort, and only if safety is at risk
Summary – Delirium
Delirium is an acute and fluctuating disturbance of attention and cognition, often secondary to a medical cause or substance exposure. It may present with hyperactive, hypoactive, or mixed features. Prompt identification of the cause, environmental optimisation, and cautious pharmacologic intervention are key to management. For a broader context, see our Psychiatry & Mental Health Overview page.