Assessing and diagnosing delirium

If you are in hospital and your symptoms suggest that you may have delirium, a clinician will assess you to see if you have delirium. They may ask if you or your family or carer have noticed any recent changes in your thinking or behaviour, such as being confused or agitated, or quieter, sleepier or less communicative than usual. If a family member or carer notices any sudden change in your mental or physical condition, it is important for them to alert a clinician. The clinician will discuss your diagnosis with you and your family or carer, and write down your diagnosis of delirium in your healthcare record. This will help other clinicians to care for you.

Using a validated tool, assess for delirium in:

• Patients with cognitive impairment on presentation to hospital
• Patients who have a sudden decline in cognitive function or change in behaviour during their hospital admission.

Seek information about the patient’s usual mental status from the patient or their family or carer, general practitioner, or other primary care provider or similar. Ask about behavioural changes, such as:

• Confusion or worsened concentration
• Agitation or restlessness
• Sleepiness, including altered levels of consciousness
• Whether the patient has been less communicative or less responsive than usual
• Whether the patient has had difficulty cooperating with reasonable requests or has had other alterations in mood.

Family members or carers are often the best source of information about acute changes in a patient’s mental status or behaviour. As delirium symptoms can vary throughout the day, more than one assessment may be required to diagnose delirium.

Identifying hypoactive, hyperactive or mixed cases of delirium is necessary to implement appropriate treatment strategies. Hypoactive delirium is more common in older people, but is often missed and has a worse prognosis than other subtypes of delirium, including worse long-term cognition when delirium has a longer duration. Delirium is less likely to be recognised in patients with frailty or dementia.

Where delirium is detected, the diagnosis is determined and documented by a clinician working within their scope of practice. Document the diagnosis to aid in transfers of care, including in handover notes, referral and discharge letters. A history of delirium increases the risk of recurrence, and documenting an episode of delirium allows for preventive measures and monitoring for new delirium in subsequent healthcare encounters.

Discuss the diagnosis with the patient and their family or carer.

Current international clinical guidelines include validated delirium diagnostic tools, some of which require training to use the tool effectively.

Ensure that systems, policies and processes are in place to support clinicians who are assessing patients with suspected delirium. The policy should ensure that a locally agreed, validated diagnostic tool for delirium is available and that clinicians are competent in its use. Educate clinicians on the use of the tool, including specified training where required and according to the tool chosen.

Develop and implement protocols for escalating care when acute deterioration occurs.

Ensure that protocols are in place to support accurate documentation and coding of delirium. Monitor rates of delirium to enable quality improvement. Awareness of delirium prevalence can assist in the effective planning of services, such as the capacity for adequate resourcing, which may include specialist nurses.

Some examples of validated tools to assess for delirium include:

• 4AT – Assessment test for delirium and cognitive impairment
• Confusion Assessment Method (CAM)
• Confusion Assessment Method for the Intensive Care Unit (CAM-ICU)
• 3D-CAM
• Delirium Observation Screening (DOS) scale
• Delirium Rating Scale-Revised-98 (DRS-R-98)
• Memorial Delirium Assessment Scale (MDAS)
• Nursing Delirium Screening Scale (Nu-DESC).

See also: 

• Screening and assessment tools for older people - Agency for Clinical Innovation, NSW

The current diagnostic standard for delirium is described in the Diagnostic Statistical Manual of Mental Disorders, Fifth Edition (DSM-5).⁶¹