Sudden confusion (delirium) – knowing the signs

Sudden confusion (delirium) can have lots of different causes. While delirium is often treatable, some causes are serious, so find out what to do if someone is affected. 

When to get emergency help

What are the symptoms?

What causes it?

When to see a doctor and getting diagnosed

What are the treatments? 

Where to find support

Sudden confusion (delirium) can have lots of different causes, from medication side-effects to health conditions. While delirium is often treatable, some of the conditions that cause it are serious, so find out what to do if someone is affected.


Delirium means confusion that comes on suddenly, usually within hours or days. 
It’s a sudden change in how the brain works, and may lead to someone forgetting their own name within just a few hours. 

It can show up in different ways – for example, someone may be unable to focus, speak, or think clearly, and they may even see and hear things that aren’t there. If someone you know is affected, it can be very distressing, as it can seem they’ve completely changed.

There are lots of possible causes of sudden confusion. While some may be serious, the condition often goes away with the right treatment.


## When to get emergency help

Call an ambulance or go to an urgent treatment center if someone suddenly becomes confused. It may indicate a serious condition that needs urgent treatment, such as a stroke or head injury.

While you’re waiting for help:

- stay with the person, and try to reassure them – tell them who you are and where you are
- use simple words and short sentences – avoid asking them lots of questions
- note down any medicines they take, if you know
- let the person move around, unless it’s dangerous for them.

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## What are the symptoms?

There are 3 different categories of sudden confusion, each with their own symptoms:

- __hyperactive delirium__ – often the easiest type to recognise. It means a person may see or hear things that aren’t there ([hallucinations](https://www.livehealthily.com/health-library/symptoms/hallucinations)), have trouble sleeping, pace around the room, lose their temper, or have mood swings
- __hypoactive delirium__ – someone may be withdrawn and less active, not respond to their surroundings, have trouble focusing and remembering things, seem sleepy, and have a reduced appetite
- __mixed delirium__ – someone moves back and forth between the symptoms of hyperactive and hypoactive delirium.

Other symptoms can include someone:

- struggling to speak clearly or quickly
- not knowing where they are (being disorientated)
- making moaning sounds, or calling out at random
- forgetting recent events – this can be similar to the symptoms of [dementia](https://www.livehealthily.com/health-library/conditions/dementia), but the 2 conditions are different
- rambling or talking in a way that doesn’t make sense
- having trouble reading or writing.

The symptoms of delirium often appear suddenly – sometimes over just a few hours – and may come and go throughout the day. Symptoms may get worse at night, when familiar surroundings look different.

## What causes it?

Sudden confusion happens when the brain doesn’t send or receive chemical messages properly. There are lots of reasons why this might happen – and sometimes it comes down to more than 1 factor.

Some of the more common causes include:

- some types of prescription medicine – such as those used to treat asthma, Parkinson’s, allergies, and pain
- low blood sugar (hypoglycemia) in those with diabetes
- recreational drug use
- alcohol poisoning or alcohol withdrawal
- dehydration
- a stroke or TIA ([mini stroke](https://www.livehealthily.com/health-library/conditions/transient-ischaemic-attack))
- carbon monoxide poisoning
- a severe [asthma](https://www.livehealthily.com/health-library/conditions/asthma) attack, or other heart and lung problems
- some types of seizures caused by [epilepsy](https://www.livehealthily.com/health-library/conditions/epilepsy)
- a head injury.

In older people, urinary tract infections (UTIs) are a common cause of delirium.

## When to see a doctor and getting diagnosed

Go back to the section __[When to get emergency help](https://www.livehealthily.com/health-library/conditions/confusion#getting-urgent-help)__ to find out what to do if someone suddenly becomes confused.  

But if you’re worried that you or a relative has gradually become more confused, book an appointment with a doctor. It may not be a sign of anything serious, but it’s important to get checked out.

Family members or close friends are usually the first to notice signs of sudden confusion happening in someone they care about – if this is you, it’s a good idea to accompany them to the appointment, if you can.

The doctor will probably ask questions about the symptoms and when they started, and go through a medical history, including any recent illnesses, pain, and medication.

They may ask a few questions to help them understand the person’s level of confusion – such as what year it is.

Your healthcare professional may also run some tests to get more insight into the underlying cause of sudden confusion. These may include:

- __a neurological exam__ – checking vision, balance, coordination and reflexes. This can work out whether a stroke, or another disease, may be causing the confusion
- __blood and urine tests__
- __brain imaging tests__ – if the diagnosis is still unclear after tests.

## What are the treatments? 

Treatment for sudden confusion depends on what has triggered it in the first place. Sometimes, it may be a case of diagnosing and treating the underlying cause. 

For example, if a healthcare professional thinks that certain medicines might be triggering confusion, they may advise stopping them. Or, if an illness has led to delirium, treating it may resolve the problem.

Once the cause has been treated and sudden confusion has gone away, a healthcare professional may advise things to help recovery, such as rehabilitation, improved nutrition, and hydration. 

## Where to find support

Watching someone you care about have sudden confusion can be very unsettling. And if you’ve experienced this yourself, you may feel shaken afterwards, and wonder how you can prevent it happening again. The following organizations offer support and information:

- The Delirium Hub via the British Geriatrics Society (UK): [www.bgs.org.uk/resources/bgs-hubs/delirium-hub](https://www.bgs.org.uk/resources/bgs-hubs/delirium-hub) 
- Family Caregiver Alliance (US): [www.caregiver.org/](https://www.caregiver.org/) 

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References

Amelia Glean

Charlotte Haigh

Dr Emily Blount

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Sudden confusion (delirium) can have lots of different causes. While delirium is often treatable, some causes are serious, so find out what to do if someone is affected.