Sudden confusion (delirium)

Someone who was themselves yesterday suddenly cannot say where they are or what the date is, loses the thread of a conversation, starts seeing things that are not there — or the opposite, falls silent and dozes all day. This is called delirium, and the essential point is that it almost never comes out of nowhere. Delirium is how the brain responds to something going wrong elsewhere in the body, so the first hours should be spent looking for the cause, not for a sedative. The cause is usually found, and found quickly: a urine infection, dehydration, a new medicine, pain, a bladder that will not empty. Sudden confusion is therefore not something to watch until morning; it is a reason to be seen the same day.

What it looks like from the outside

Delirium is recognised not by a single sign but by how fast it arrives: the change takes hours or a day or two, and relatives can usually name the day things stopped being right.

• Attention falls apart. The person cannot follow a conversation, drifts off mid-sentence, asks you to repeat things, cannot manage a two-step request.
• They do not know where they are or what time of day it is: getting dressed for work at night, not recognising their own flat, taking a hospital bay for their bedroom.
• Speech and thinking become broken. Sentences trail off, words are hard to find, answers do not match the question.
• Hallucinations and false beliefs appear. Usually visual: people in the room, animals, insects. Sometimes a conviction that they have been robbed or that someone means them harm.
• The state fluctuates. Almost normal in the morning, clearly worse by evening and at night. That swing within a single day is so typical that on its own it points to delirium.
• Sleep flips over: wakeful and anxious at night, drowsy during the day.

You can test it with plain questions: what is your name, how old are you, what day is it, where are we. If the answers are hesitant or absent, and this person answered easily before, it is a medical situation and not stubbornness or simple tiredness.

The quiet delirium that is mistaken for weakness

People think of delirium when someone is agitated, trying to leave and talking to an invisible visitor. But in many, and especially in older people, it works the other way round: they lie still, barely move, answer in single words after a long pause, refuse food and complain of nothing. This is the quiet, or hypoactive, form. It is no rarer than the noisy kind and it is missed far more often, because from the outside it looks like someone who has simply gone downhill, is sleeping off an illness, or is depressed.

The danger is that the cause is exactly the same and exactly as urgent. Pneumonia, dehydration, sepsis and too much sleeping medication all present like this — as fading, not as uproar. If an older person has become markedly slowed over a day or two and has stopped getting up and talking, that is looked into today rather than left to rest.

This is not dementia and not old age

Confusion in an older person is nearly always put down to age, and that is the commonest and costliest mistake. Age alone does not leave anyone disorientated in the space of one evening.

Telling delirium from dementia is easier than it sounds: the difference comes down to speed and steadiness.

• Onset. Delirium arrives over hours or days and the family can give a date. Dementia builds over months and years and nobody can say when it began.
• Fluctuation. In delirium the state shifts within a single day, better at times and worse at others. In dementia it is level from one day to the next.
• Attention. Delirium breaks the ability to concentrate first. In dementia memory goes first and attention holds up for a long time.
• Level of awareness. In delirium the clarity of consciousness itself changes: the person is here, then drifts away. In dementia they are awake and present in the moment, even while forgetting.
• Reversibility. Delirium settles once the cause is removed. Dementia does not.

One does not rule out the other: delirium comes especially easily to someone with dementia, and a sharp deterioration in that person is nearly always a new acute cause rather than the illness taking a step forward. "They have dementia, what did you expect" explains nothing about a sudden change.

What has to be looked for the same day

There are many causes, but the common ones form a narrow circle and nearly all of them are fixable: remove the cause and the person usually returns to how they were. Surroundings sit slightly apart — a move, a hospital ward, an anaesthetic, a sleepless night, darkness, being without glasses and hearing aid. They do not cause delirium, but they clear the way for it.

• Infection. In older people confusion can be the only sign of an infection, with no fever and no complaints. A urine infection or pneumonia are the usual culprits.
• Dehydration and disturbed blood salts: hot weather, vomiting, diarrhoea, water tablets, or simply drinking too little. A low sodium level produces confusion very characteristically.
• Medicines are the most underrated cause. Sleeping tablets and tranquillisers, strong painkillers, antihistamines and travel sickness remedies, drugs for incontinence and for spasm, some drugs for parkinsonism and depression. Starting one is a risk, so is a dose increase, and so is the sheer number of them: five or six together do what none does alone.
• Abrupt withdrawal. Stopping alcohol in a daily drinker, or stopping sleeping tablets or tranquillisers, is a classic cause of severe delirium one to three days after the last dose. Say so plainly to the doctor, however awkward it feels.
• Alcohol and other substances: intoxication, poisoning, drug use.
• Low blood sugar. In someone with diabetes this is the first thing checked and the first thing put right, in a minute.
• Urinary retention and severe constipation. A full bladder alone can tip an older person into delirium, and a catheter settles it in half an hour.
• Pain the person cannot report: after a fracture, from a pressure sore.
• Lack of oxygen: a flare of lung disease, an asthma attack, heart failure, severe anaemia.
• Stroke and transient ischaemic attack.
• Head injury, including a mild knock a week ago in an older person or in anyone taking blood-thinning medicines.
• Carbon monoxide poisoning — suspect it if several people in the same house feel unwell and feel better outside it.
• A seizure and the state that follows it.

When to call an ambulance

Sudden confusion is by itself reason enough for urgent help. Do not try to work it out at home and do not diagnose from the internet. Call an ambulance — the single European number 112 works in Spain, Italy, Portugal, Poland and Ukraine — if the confusion came on suddenly, and all the more so with any of the following:

• the face has dropped on one side, an arm or leg will not lift, speech is slurred, vision has gone on one side — this is what a stroke looks like, and here minutes count;
• the person does not respond or cannot be woken, or there has been a faint or a fit;
• sudden severe headache, vomiting, dislike of light, a stiff neck, a rash that does not fade when a glass is pressed on it;
• fever with shivering, fast breathing, cold clammy skin, little urine — signs of severe infection;
• difficulty breathing, blue lips, chest pain;
• confusion in someone with diabetes: give a sugary drink or a glucose tablet if they are conscious and swallowing safely, and still call for help;
• there has been a head injury, even several days ago;
• they drank daily and stopped abruptly, with tremor, sweating and fear;
• you suspect poisoning by medicines, drugs or carbon monoxide.

Do not drive them yourself if they are agitated or may lose consciousness. Take all their medicines with you — boxes, blister packs or at least a list. It is the single most useful thing you can hand the doctor.

What to do while help is on the way

A great deal rests on whoever is there in those hours, and almost all of it comes down to calm and simplicity.

• Do not leave the person alone. Give your name, say where they are and what day it is, and repeat it as often as needed.
• Use short sentences and one question at a time, in an ordinary voice. Do not argue with hallucinations: say that you cannot see it, but that you believe they are frightened.
• Put their glasses and hearing aid on if they use them — half the misunderstanding goes with that alone.
• Leave a soft light on, cut the background noise, ask visitors to step out, offer a drink of water.
• Do not hold them down or tie them. If they are walking about the room and it is safe, let them: clear cables and rugs from the floor and lock the door and windows.
• Write down when the change started, which medicines were begun or stopped in the last few days, how much alcohol they have drunk, and when they last passed urine and ate.

How doctors work it out

The tests are not there to confirm the delirium, which is plain enough, but to find the cause, and they are usually quick: asking whoever came along what the person was like a week ago, an examination, blood pressure, pulse, temperature, oxygen level and blood sugar, blood and urine tests, an electrocardiogram. Then, depending on the picture, a chest X-ray, a urine culture, and a head scan after injury, with focal neurological signs, or when the deterioration remains unexplained.

A separate and very important part is a review of every medicine: the doctor looks for what was started, stopped or doubled in the past few days. Treatment has two halves — remove the cause that was found, and support the person while they come back. Sedatives are used reluctantly, at the smallest dose, and only when agitation threatens safety, because on their own they do not treat delirium and can prolong it.

How long it lasts and how to avoid a repeat

Once the cause is gone, clarity returns, but not at once: in a day or two in younger people, often over a week or two in older ones, while weakness, poor concentration and broken sleep last longer. Part of what happened will not be remembered at all, part will be remembered as a frightening dream. It is worth talking about calmly, because many people are later ashamed of how they behaved and say nothing.

Having had delirium is a sign that the brain is vulnerable and that it may happen again with the next illness or operation. Simple things lower the risk: enough to drink, regular meals, glasses and hearing aid within reach, daylight by day and darkness at night, walking early after surgery, treating pain and constipation, and reviewing the medicine list once a year. If an admission or an anaesthetic is coming up, say in advance that there has been a delirium before: it changes the care given.

Online consultation

If the confusion is happening right now, do not write to us — call an ambulance, because this is dealt with in person and urgently. An online consultation is useful around that episode. Beforehand, a doctor can help you tell an acute change from a slow decline of years, and say what to measure, what to note down and what to bring. Afterwards, they can go through the discharge letter and the prescriptions, explain why delirium happened to this particular person, help review a long medicine list and put together a plan in case it recurs. And they will answer the question people ask most: whether an episode of delirium means dementia has started.

This material is for information only and does not replace medical advice.