Delirium in older people: sudden confusion, causes and care

Delirium is the brain reacting to a separate problem. The NHS sudden-confusion page lists a person who may be unable to think or speak clearly or quickly, not know where they are, struggle to pay attention or remember things, or see or hear things that are not there. Alzheimer's Society adds that the common thread is that the person becomes less responsive or less alert to what is happening around them.

It is not the same thing as dementia, although the two can look alike to someone who does not know the person well. The table below sets out the differences described by Alzheimer's Society. One important exception it notes is dementia with Lewy bodies, which shares many symptoms with delirium and can be hard to tell apart without knowing the person.

Hyperactive delirium looks like restlessness, pacing, agitation, resisting personal care, suspicion of other people, or seeing someone by the bed who is not there. Hypoactive delirium is the opposite: the person seems withdrawn, sluggish or very sleepy, moves and talks less, eats and drinks less, and struggles to stay focused when awake. Mixed delirium swings between the two, sometimes within a single day.

Alzheimer's Society points out that hypoactive delirium is easy to miss because the person may simply look tired, and may go unnoticed when carers or staff are busy. For families, the practical lesson is that a normally chatty parent who has become unusually quiet and drowsy deserves the same urgency as one who has become agitated.

Often there is more than one cause, which is why a thorough assessment is needed. The NHS lists common causes of sudden confusion including infection (urinary tract infections are a common cause in older people or people with dementia), a stroke or TIA, low blood sugar in people with diabetes, a head injury, some prescription medicines, alcohol withdrawal or poisoning, carbon monoxide poisoning, a severe asthma attack or other lung or heart problems, and certain seizures. Alzheimer's Society adds pain, a major operation with general anaesthetic, fractures, poor nutrition or dehydration, constipation, urinary retention, low blood oxygen, and abnormal salt or sugar levels.

Anyone can develop delirium, but Alzheimer's Society lists these as raising the risk:

• Having dementia (the biggest single factor).

• Being older than 65, frail, or living with several medical conditions.

• Poor hearing or vision, an unfamiliar environment, or being sleep deprived.

• Not being able to sit up or move around.

• Taking certain medicines, particularly those that cause drowsiness.

• Having had delirium before.

The NHS says not to try to self-diagnose and to get medical help immediately if someone suddenly becomes confused, going to A&E or calling 999. It says not to drive yourself, and to bring any medicines. Alzheimer's Society advises that for a person with dementia you call the GP or NHS 111 straight away rather than hoping symptoms settle, and call 999 if the person seems seriously unwell or you are worried for anyone's safety. A GP would also want to hear about gradual forgetfulness or confusion, which the NHS says can sometimes be a sign of dementia.

While waiting, stay with the person, tell them who you are and where they are, use simple words and short sentences, and note down their medicines. The NHS advises against asking lots of questions and against stopping them moving around unless they are in danger. Alzheimer's Society suggests jotting down when the change began, how the person differs from usual, whether they are seeing things that are not there, and any recent illness, injury or medicine change.

• If your concerns about someone in hospital are not being heard, Alzheimer's Society says that in England Martha's Rule allows an urgent review by another clinical team; Wales is introducing a similar system called Call for Concern.

• Pack glasses, hearing aids, medicines and something familiar such as a photograph if admission is likely.

Alzheimer's Society explains that a doctor or nurse should assess the person's mental state as soon as possible. A short screening tool called the 4AT checks alertness, awareness, attention and whether symptoms come and go; it takes around two minutes. Once delirium is identified, the team looks for the cause with a physical examination and, where needed, blood tests, X-rays or other scans.

The only way to treat delirium is to resolve what is causing it. Alongside that, Alzheimer's Society lists helpful measures that staff, family and friends can use: calm short sentences, reminding the person where they are and who you are, familiar objects from home, regular eating and drinking, clean and working glasses and hearing aids, a clear 24-hour clock and calendar, a healthy sleep routine, and getting up and about as soon as it is safe. It says medicines for hallucinations, delusions or aggression should be considered only if the person is a risk to themselves or others or is severely distressed, and then a doctor may try a low dose of a sedative or an antipsychotic for a few days.

For many people symptoms improve within a few days once the causes are treated. Alzheimer's Society cautions that some people do not make a quick or full recovery and may still have problems with memory and thinking weeks or months later, particularly after delirium following a major operation. Prolonged and severe delirium over several weeks can increase the risk of developing dementia; the charity is clear that this does not mean delirium causes dementia, but it may speed up decline in someone already having memory and thinking problems.

After leaving hospital a person may need more help than before with everyday tasks. The hospital team can advise on caring for them and arrange extra health and social care support. Families may want to ask for the delirium to be recorded in discharge paperwork so the GP knows to review memory and function later.

Alzheimer's Society says that with the right care delirium can often be prevented, and that when someone comes into hospital or a care home, staff may check whether they are at risk and put measures in place. Families can support this by bringing in hearing aids and glasses, helping with drinks and meals, encouraging movement, keeping a familiar routine and flagging any new drowsiness-causing medicines to the pharmacist or doctor. Avoiding new, busy or confusing environments where possible is another point the charity makes.