- Delirium is a sudden change in your thinking and behaviour.
- Delirium is often caused by changes in your health, such as an infection or a medicine change.
- If you are in hospital and at risk of delirium, your doctor will provide care to stop delirium from happening.
What is delirium?
Delirium is a common problem. It appears as a sudden change in your thinking and behaviour. Delirium happens quickly and only lasts for a few days.
Delirium often happens in older people, but it can happen at any age. People who have delirium when they are in hospital are at a higher risk of other medical complications.
What are the symptoms of delirium?
Someone with delirium may:
- be confused and forgetful
- be unsure of the time or where they are
- struggle to pay attention
- act differently from normal
- be unsettled, sleepy, or quiet and withdrawn
- have changes to their sleeping patterns
- be scared, upset, irritable, angry or sad
- see things that are not there (hallucinations)
- wet or soil themself (incontinence)
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What are the causes of delirium?
Delirium is often caused by changes in your health, such as an infection or a medicine change.
It may also be from:
- difficulty going to the toilet (constipation or not being able to empty bladder)
- not drinking or eating enough (dehydration or malnutrition)
- bad pain
- medicines, including ‘over-the-counter’ medicines
- heavy alcohol consumption
- withdrawal from alcohol, cigarettes or medicines, particularly sleeping pills
- changes in your environment, such as being hospitalised
It is not always possible to find the cause of delirium.
Who is at risk of delirium?
People at risk of delirium include those:
- aged over 65 years, or over 45 years for Aboriginal and/or Torres Strait Islander people
- taking multiple medicines or those who have had recent changes to medicines
- who have had recent surgery
- with depression
- with poor eyesight and/or hearing loss
- who are very sick or frail
- with a cognitive impairment, including dementia, intellectual disability or brain injury
- who have had delirium before
How is delirium diagnosed?
A doctor will check you for delirium. They may ask if there have been any recent changes in your thinking or behaviour.
If you notice any sudden change in the mental or physical condition of a family member or friend, it is important to tell a doctor.
Once delirium is found, the next step is to find and treat the cause.
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How is delirium treated?
Delirium treatment relies on finding the underlying cause. Your doctor will examine you and run tests to find the cause of your delirium.
These might include:
They will also ask you about the medicines you are taking and whether you are in pain.
You will be treated for anything that may be causing your delirium. This might mean that:
- your medicines are changed
- you are given more fluids
- you are treated for an infection
Can delirium be prevented?
In many cases delirium can be prevented.
If you are in hospital and at risk of delirium, your doctor will provide care to stop delirium from happening.
This care may include:
- changing your medicines
- giving you more fluids
- helping you stay mobile
What are the complications of delirium?
If you have delirium in hospital, your care will help stop any complications.
This might include:
People who have had delirium are more likely to get delirium again.
Delirium and dementia
Dementia is a condition where a person’s memory, thinking, understanding or judgement can be affected. It gets worse with time. Delirium causes about one in 10 cases of dementia in Australia.
Resources and support
If you want to know more about delirium, talk to your doctor. You can also call healthdirect on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak to, 24 hours, 7 days a week.
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Last reviewed: September 2022