Call our free Dementia Helpline 0800 888 6678
Donate

Delirium and dementia: symptoms, causes and treatment

Delirium is a state of sudden, intense confusion. It is common in older people and those with dementia and can make them increasingly anxious and distressed. Our specialist Admiral Nurses explain the signs to be aware of and how you can help a person with dementia who is experiencing delirium.

What is delirium?

Delirium is a state of intense mental confusion that comes on suddenly. It can have a big impact on the way a person behaves and functions, especially if they have dementia.

People with delirium typically become confused and/or disorientated and have difficulty concentrating. It can be very distressing for the person experiencing it and their carers.

Types of delirium

There are three types of delirium: hyperactive, hypoactive and mixed. For older people, including those with dementia, hypoactive and mixed delirium are the most common.

Hyperactive delirium

Hyperactive delirium causes confusion that fluctuates throughout the day. A person who is experiencing hyperactive delirium may:

  • hallucinate: for example, seeing or hearing things that are not really there
  • be restless or agitated: they may fidget, make repetitive movements, pace or seem unable to stay still
  • be resistant to receiving support or personal care, possibly becoming aggressive towards their carers
  • be unusually wary of other people
  • believe that people are trying to harm them
  • not recognise where they are, or who the people around them are
  • be confused about the time or day

Hypoactive delirium

Hypoactive delirium is characterised by the person becoming less responsive. They may:

  • be unusually sleepy and hard to rouse
  • struggle to focus when they are awake
  • lack appetite
  • seem withdrawn, sluggish or tired
    move around less
  • interact less with the people around them

Mixed delirium

When someone is experiencing mixed delirium, they will have symptoms of both hyperactive and hypoactive delirium and may switch between them. A person with mixed delirium may be sleepy and unfocused one day, and agitated and restless the next.

Symptoms of delirium

It can be difficult to recognise delirium in people with dementia because many of the symptoms are similar: for example, confusion, memory loss and problems with concentration. However, it is important to know the signs and seek medical help quickly if you spot them.

The symptoms of delirium may be cognitive (affecting the person’s ability to remember, think and communicate), behavioural and/or physical. They include:

  • a sudden change in mental state and/or behaviour
  • disorientation: much more unsure of where they are or what day/time it is
  • paranoia and false beliefs, such as thinking someone is trying to harm them
  • poor concentration – unable to focus on a conversation with anyone
  • sudden increased memory loss
  • memory loss
  • unusual drowsiness – often missed or put down to tiredness
  • feeling agitated and seeming much more restless
  • irritability or aggression (eg shouting)
  • hallucinations (seeing or hearing things that are not there)
  • difficulty speaking clearly and following conversations
  • vivid dreams – waking up and unable to settle when this is unusual for them
  • physical changes, for example, in appetite, thirst or mobility
  • falls

Older people with delirium and dementia often need longer stays in hospital, are more prone to falls or accidents, and are more likely to be moved into a care home.

How common is delirium?

Delirium is most common in older adults – particularly those over 80. There is also a strong link between delirium and dementia. Delirium is particularly common on hospital wards, affecting approximately 25-30% of older people and up to 50% of people with dementia. People living in care homes are also more prone to delirium.

What are the causes of delirium?

There are a number of reasons why someone may develop delirium.

Medical conditions

Medical conditions that can cause delirium include:

  • an infection such as a urinary tract infection (UTI)
  • Medications such as morphine (opioids), sedatives and antipsychotics
  • post-surgery medications
  • a stroke or transient ischaemic attack (TIA), often known as a ‘mini stroke’
  • high and low blood sugar (low blood sugar should be monitored in people with diabetes in particular)
  • pain – can be ‘hidden’ (for example, toothache or arthritic pain)
  • head injury
  • constipation or urine retention
  • not eating enough
  • not drinking enough (dehydration)

Environmental factors

Environmental factors that can cause delirium include:

  • being in an unfamiliar or distressing environment such as a hospital
  • excessive noise and disturbances
  • exposure to bright artificial light
  • lack of exposure to natural daylight

Medication

Some types of medication can make delirium more likely, especially if the person is taking multiple medications.

Surgery

Up to 50% of older people who have surgery develop delirium. People who have hip surgery are at a particularly high risk, with research suggesting that 70-80% develop delirium.

Age

Delirium is more common in people over 65; however, younger people can also be affected.

Diagnosing and treating delirium

Diagnosing delirium

If a person is experiencing symptoms of delirium, it is important to seek medical advice. It can often be diagnosed based on their symptoms. Their healthcare professional should consider their:

  • alertness: are they drowsy and withdrawn, or restless and agitated?
  • awareness: do they know what year it is and where they are?
  • attention: eg can they name the months of the year backwards?
  • acute or fluctuating changes: did the changes come on suddenly, and are they varying throughout the day?

The doctor may request blood and urine tests to check for underlying causes, such as an infection, constipation or difficulty passing urine. They should also review any medication that could be contributing to the delirium.

Treating delirium

Treating delirium usually involves addressing any underlying causes. For example, if the person has an infection, they may be prescribed antibiotics, or if they are constipated, they may be given laxatives.

Medication is not usually given for delirium itself. If the person is particularly distressed, they may be given a short, low-dose course of medication such as a sedative or antipsychotic. However, for some people, particularly those with Lewy body dementia, these medications can make delirium worse, so they should only be used if absolutely necessary – for instance, if the person is at risk of harming themselves or someone else.

Sometimes, there is no treatable cause of delirium; in these cases, the person may just need support, time and rest to recover, ideally in a calm and familiar environment. Family members can help by reassuring them that they are safe, making sure that they are wearing their glasses or hearing aids, and encouraging them to eat and drink.

Supporting someone with delirium

Delirium can be serious, so it is vital that the person receives medical assistance as soon as possible if you notice the symptoms. If the person is at home, contact their GP and ask for an urgent appointment. If they are in hospital, tell the nurse or doctor who is looking after them. If they are in a care home, tell a carer.

If you think the person is seriously or suddenly unwell, take them to A&E or call 999 for an ambulance: in rare cases, delirium or its underlying causes can be life-threatening.

You could also try these ideas to try to ease the person’s distress:

  • Keep calm and reassure the person – you might need to remind them who you are, where they are and what day it is
  • Speak in short, simple sentences
  • Try to distract the person with activities like watching TV, listening to music or looking at photos
  • Encourage the person to eat and drink, for example by offering their favourite foods
  • Help the person find the toilet if needed
  • Stay with them if they are walking around in case of falls
  • Keep a dim light on at night
  • Avoid disagreeing with the person, even if they are saying unusual things – instead, try to change the topic of conversation
  • If the person is in hospital, ask if you can stay with them – many hospitals support John’s Campaign, which encourages unlimited visiting for people who care for someone with dementia

Recovering from delirium

About 60% of people with delirium recover within a week. Some people, however, take longer to recover, and some never return to exactly how they were before – this is more likely if the person is living with dementia. You should also consider whether the person may be in pain (especially chronic pain such as arthritis), which has worsened, and they are struggling to communicate.

Can delirium be prevented?

Delirium cannot always be prevented, but there are things you can do to reduce the risk.

  • Make sure the person wears their glasses and/or hearing aids if they need them
  • Try to ensure they get enough sleep
  • Encourage them to eat and drink regularly. In particular, eating plenty of fruit and vegetables and increasing fluids can help prevent constipation
  • Help them stay mobile, even if just by walking around the room or doing some stretches in their chair
  • Make sure they are practising good hygiene, for example by washing their hands after using the toilet, cleaning medical devices like urinary catheters properly and keeping wounds clean and dressed
  • Help them take part in activities that they enjoy, like doing puzzles, knitting, going for walks or seeing friends and family
  • If they are in hospital, ask the staff to avoid moving them to a different bed or ward if possible

How does delirium differ from dementia?

When someone has delirium, the symptoms come on very quickly, over the course of one or two days or even a few hours, whereas dementia develops gradually over months or years. The symptoms of delirium also tend to vary a lot throughout the day.

How we can support you

To speak to a specialist dementia Admiral Nurse about alcohol-related brain damage or any other aspect of dementia, please call our free Dementia Helpline on 0800 888 6678 (Monday-Friday 9am-9pm, Saturday and Sunday 9am-5pm, every day except 25th December or email helpline@dementiauk.org.

If you prefer, you can book a phone or video appointment with a specialist dementia Admiral Nurse in our virtual clinics.

Frequently asked questions

Sundowning is a state of intense confusion that occurs in many people with dementia, typically in the evening. A person who is experiencing sundowning will often be very anxious and confused, with a strong sense of being in the wrong place. Although the symptoms can be similar, sundowning is not a type of delirium. Read more about sundowning.

Most people with delirium start to improve within a few days, especially if the root cause is identified and addressed. Some people, however, take longer to recover and may have symptoms of delirium for weeks or months after initially becoming unwell. Some people never fully return to how they were before.

There is no specific cure for delirium. However, it can often be successfully treated if any underlying causes are addressed, for example by prescribing medication to treat an infection, and the person is well supported.

Delirium can indicate an infection which, if not treated, could lead to medical complications such as sepsis, which can become life-threatening.