DELIRIUM: diagnosis, prevention and management - Clinical Guideline 103

NCGC National Clinical Guideline Centre

Commissioned by the National Institute for Health and Clinical Excellence July 2010

Delirium, sometimes named ‘acute confusional state’, is a common clinical syndrome characterised by disturbed consciousness and a change in cognitive function or perception that develops over a short period of time (usually 1-2 days).

Although the clinical presentation of delirium differs considerably from patient to patient, there are several characteristic features that help suggest the diagnosis. The standard criteria for delirium are described in the ‘Diagnostic and Statistical Manual of Mental Disorders’ [DSM-IV] (1994):

• Disturbance of consciousness (i. e., reduced clarity of awareness of the environment) with reduced ability to focus, sustain, or shift attention.
• A change in cognition (such as memory deficit, disorientation, language disturbance) or the development of a perceptual disturbance that is not better accounted for a by pre – existing, established, or evolving dementia.
• The disturbance develops over a short period of time (usually hours to days) and tends to fluctuate during the course of the day.
• There is evidence from the history, physical examination, and laboratory findings that: (1)n the disturbance is caused by the direct physiological consequences of a general medical condition, (2) the symptoms in criteria (a) and (b) developed during substance intoxication, or during or shortly after, a withdrawal syndrome, or (3) the delirium has more than one aetiology.

Features of delirium are recent of fluctuating awareness, impairment of memory and attention and disorganised thinking.

Additional features may include hallucinations and disturbance of sleep – wake cycle. There are three clinical subtypes of delirium: hyperactive (characterized by hallucinations, delusions, agitation, and disorientation); hypoactive (characterized by sleep state, uninterested in activities of living, often unrecognized or labeled dementia); or mixed (patents can move between the two subtypes). Delirium may be present at the hospital admissionl or long-term care (prevalent delirium) or it may develop during the hospital/long – term care (incident delirium). It can be difficult to distinguish between delirium and dementia and some patients may have both conditions (delirium on dementia).

Delirium is a common and serious condition that I associated with poor outcomes. However, it can be prevented and treated if promptly dealt.

A guidance to improve methods of appropriate identification, diagnosis, prevention and management of delirium is needed. Failure to diagnose delirium or misdiagnosis (mainly as dementia), can lead to medical emergencies being missed (ie. Appropriate assessment and treatment may be omitted) and inappropriate treatment being given. Delirium is often preventable and improvements in care practices and other treatments are needed. The improved management of delirium has the potential to generate cost savings.

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