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The Age Space Guide to Delirium

The Age Space Guide to Delirium

Delirium is a mental condition that is often a symptom of another underlying illness. Delirium in the elderly can be hard to spot, but it is important to look out for, as it can end up being fatal. Older people, particularly those who have recently left hospital or are in long-term care, are more at-risk of delirium.

age space think delirium

Delirium is often mistaken for dementia, due to both conditions having similar symptoms. However, your parent being confused or not-acting-themselves does not necessarily mean that they have dementia: they may have delirium, which is treatable. In most cases, delirium is treated by addressing the underlying health problem that is causing it.

In this guide you can find out more about the signs of delirium, what causes it and what to do if you suspect the person you’re caring for has delirium.

What is delirium?

Delirium is a state of confusion that a person experiences caused by an underlying physical condition or health problem. This ‘acute confusional state’ may make the person unsure about where they are, what they are doing, or who they are with. 

Delirium usually comes on rapidly, and can last for between a few hours and a few weeks. Dr Alex Bailey, an old-age psychiatrist, describes delirium as being like “if you’ve ever had a really bad flu and it’s so bad you feel really out of it, you might have some strange experiences, you can’t concentrate, your thinking is all over the place, you feel feverish – essentially that is delirium.”

You can hear more of Dr Alex Bailey’s thoughts about delirium from the Age Space podcast, where he discusses delirium and depression in the elderly with Age Space founder Annabel James. Click on the video on the right to hear everything he had to say about delirium.

What are the symptoms of delirium?

There are a number of symptoms of delirium to look out for in the person you are caring for. Delirium symptoms may not all present all of the time, can fluctuate hour-to-hour, and tend to get worse in the evenings. In some cases, delirium is identified initially from a person being labelled as ‘not acting themselves’.

There are 3 different types of delirium: hyperactive delirium, hypoactive delirium, and mixed delirium (a mix of hyperactive and hypoactive). Each type has its own additonal symptoms to look out for, see below.

Some of the most common general symptoms of all types of delirium to look out for are:

  • Fluctuations in alertness and concentration
  • Rapid and unexplained changes in mood
  • Poor memory and recollection of recent events
  • Disorientation about where they are and who they are with
  • Visual and auditory hallucinations
  • Fear or paranoia
  • Saying things that don’t make sense

Hyperactive delirium and hypoactive delirium symptoms

Hyperactive Delirium Symptoms

Hyperactive delirium is easier to identify, as the person tends to be more restless and aggressive, therein drawing attention to their condition. Common symptoms of hyperactive delirium include:

 - Aggression or combativeness

 - Lack of co-operation with reasonable requests

 - Periods of severe anger or extreme elation 

 - Restlessness 


Hypoactive Delirium Symptoms​

Hypoactive delirium can be more difficult to identify, but is more common. People tend to become more withdrawn, and therefore not draw attention to their condition. Common symptoms of hypoactive delirium include:

 - Being very tired and lethargic

 - Drowsiness, staring into space or seeming 'in a daze' 

 - Inability to focus on things

People who have mixed delirium will switch between showing symptoms of both hyperactive and hypoactive delirium. For example, they may appear very aggressive and restless for a period of time, but later that day appear very withdrawn and dazed. 

What's the difference between delirium and dementia?

Delirium is commonly mistaken for dementia, due to the similar symptoms. In some cases, people do have both – but this is not usually the case. It is important that you know how the symptoms of delirium and dementia are different from each other.

There are 2 major differences between dementia and delirium to look out for:

what is delirium

1. Delirium has a much faster onset than dementia, with people usually showing altered behaviour within a couple of days, rather than gradually over time. 

2. Delirium and dementia produce different types of confusion. With dementia, thoughts are ordered. With delirium, thoughts are disordered. Dr Strain, an expert on delirium, provides this simple anaology: “If you asked a patient with dementia, what they had for breakfast, they might tell you that they had cornflakes, when in reality, they had toast. If you asked a patient with delirium the same question about their breakfast, they might start telling you about the weather.”

In people living with dementia, delirium can usually be identified from a sudden, sharp decline.

What causes delirium?

There are a number of potential causes of delirium, and sometimes more than one of them may be contributing. Generally, delirium is caused by one or more underlying health issues. This is particularly true in older people, who are more likely to have multiple health problems. 

Delirium is most common in people who are in hospital, or have recently left hospital. Delirium is also more common in people who already have problems with their memory, including those with dementia. 

Some of the most common causes of delirium are:

  • Dehydration
  • A chest or urine infection
  • Recent surgery
  • Side effects of medicine
  • Pain
  • Constipation
  • Kidney or liver problems
  • A high fever
  • Drugs or alcohol withdrawal
  • Terminal illness
  • Stroke
  • Being in a new or unfamiliar location

You can learn more about treating each of these causes from the NHS website.

How is delirium treated?

If somebody is showing symptoms of delirium, you should urgently seek professional medical help. It can be a symptom of very serious illnesses, which can potentially be fatal.

If your relative is experiencing delirium you should call 111 or book an appointment with a GP as soon as possible. 

The primary way of treating delirium is by addressing the underlying physical cause of the delirium. This means that a medical professional will need to identify what is causing the delirium. If the medical professional thinks that it is caused by a urine infection, for example, then they may prescribe a treatment of antibiotics.

Because the person experiencing delirium is confused, they may find it difficult to express other symptoms that they are experiencing, or provide correct information to the medical professional. This makes it essential that somebody with delirium is accompanied by a family member or carer that knows them well and can provide correct information.

How can I prevent delirium?

The most effective way of preventing delirium is by ensuring a generally good standard of care. This includes ensuring that the person you’re caring for stays hydrated and well-nourished, is sleeping well, and has regular medical check-ups. It is thought that 1 in 3 cases of delirium is preventable. 

Delirium FAQs

How long does delirium last?

Delirium can last for between hours and months, and can endure long after the infection has been treated. 

How can I comfort someone with delirium who is distressed?

Try to make them feel calm and reassured. It may help to explain to the person that they have delirium, and that this is why they are confused.

- Consistent reminders of where they are can help.

- Having family and friends visit may also have a positive effect.

Should I speak to the care home my parent is in about delirium?

Yes. If you visit your relative and they do not seem themselves, you should ask the staff at the care home to keep an eye out for the symptoms of delirium.

How does a person feel after delirium?

A person who has experienced delirium may have distressing memories in the weeks and months afterwords. These can be related to hallucinations they experienced, or lingering feelings of fear or anxiety.

How does infection cause delirium?

Any illness that leads to inflammation and infection can interfere with brain function, which can cause delirium. Additionally, any condition that reduces the amount of oxygen getting to the brain can lead to delirium.

Is delirium a form of dementia?

No, delirium is not a form of dementia. Delirium has a much faster onset than dementia, and is usually treatable, whereas dementia is not. In some cases people can have both delirium and dementia. People with dementia are more at risk of delirium.

What practical steps can I take to prevent my relative's delirium from getting worse?

Some other practical steps that you can take to prevent your relative's delirium from getting worse are:

- Have natural lighting indoors

- Keep noise levels low

- Offer reminders of what time it is - perhaps providing a large clock near them

"If you asked a patient with dementia what they had for breakfast, they might tell you that they had cornflakes, when in reality they had toast ... If you asked a patient with delirium the same question they might start telling you about the weather."
Dr David Strain
Dr David Strain
Senior Clinical Lecturer at the University of Exeter Medical School