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Dr. Chrysoula I. Liakou MD, PhD
Call 112 now if any of these apply
Sudden confusion is called delirium, and it is a medical emergency until proven otherwise. Call 112, or get someone to emergency care now, if a person of any age:
- has become confused suddenly, over hours or days, even if it comes and goes or briefly clears;
- is confused with a drooping face, weakness in one arm, slurred speech, sudden severe headache or sudden vision loss (possible stroke);
- has diabetes and becomes confused, shaky, sweaty or drowsy (possible low blood sugar): if they are fully awake and can swallow safely, give something sugary, and call 112 if they do not recover within minutes;
- is confused with fever, shivering, fast breathing, a fast heartbeat, or a new rash that does not fade under a glass (possible severe infection, including meningitis);
- becomes confused after a head injury or a fall, however minor it seemed;
- is confused after heavy drinking has suddenly stopped, or with a suspected overdose or poisoning, including possible carbon monoxide exposure;
- is becoming impossible to keep awake, or cannot be woken properly.
This applies just as strongly to someone who already has dementia: a sudden change on top of dementia is still delirium, and still an emergency.[1] Do not wait to see if the morning is better.
If you are having thoughts of harming yourself, call 112 in an emergency. You can also find your national crisis helpline at findahelpline.com. You do not have to wait for an appointment.
- Treated online: Assessment only, for confusion that has developed gradually over months; sudden confusion (delirium) needs 112 or emergency care, and dementia is diagnosed in person.
- What it is: confusion is a change in thinking, attention or memory; sudden confusion over hours or days is delirium, a treatable emergency, while slow change over months points to dementia, depression, medicines or a treatable medical cause.
- Common causes of delirium: infection (urine and chest infections above all), new medicines or dose changes, dehydration, low sodium, low blood sugar, stroke, head injury and alcohol withdrawal; most are treatable once found.
- Medicines that cloud thinking: sedatives, sleeping tablets, strong painkillers, some bladder medicines and older antihistamines, alone or in combination, especially after 65.
- How long: delirium usually clears within days to a few weeks once its cause is treated, though it can take longer in older people and in people who already have dementia.
- Emergency: call 112 for confusion that is new over hours or days, confusion with a drooping face, weak arm or slurred speech, with fever, after a head injury, in someone with diabetes, or with drowsiness you cannot rouse them from.
A video consultation is only appropriate when none of the emergency features above apply and the change has developed gradually, over months. If you are reading this page for a relative whose confusion is new today, the red box is your answer: use 112 or emergency care now. If the story is slower, an online doctor can help you work out what is happening and what to do next.
Can an online doctor help with confusion?
Yes. Confusion developing over hours or days, called delirium, is a medical emergency until proven otherwise: common causes include infection, stroke, low blood sugar, dehydration, medicine side effects, head injury and alcohol withdrawal.[1] Call 112 or get emergency care the same day. Gradual change over months is different: it needs assessment, not an ambulance, and that assessment can start online.
How an online consultation helps with confusion
- Sorting sudden from gradual: The single most important job with confusion, done first and honestly. If anything in your description points to delirium, the doctor stops and directs you to emergency care immediately, including mid-consultation.
- A calm place to lay out the story: Most of these consultations are booked by a worried son, daughter or partner. The doctor helps you turn months of small incidents into a usable timeline, with your relative on screen alongside you where possible.
- The work-up, ordered properly: Gradual cognitive change always deserves a physical check: blood tests for thyroid, vitamin B12, blood sugar and more, directed locally, plus a hard look at the medication list, because treatable causes hide there.[2]
- The memory-clinic route, explained: If the picture fits a true memory decline, the doctor explains the referral pathway to a memory clinic or neurology service, what the testing involves, and why going early is worth it.
What causes sudden confusion?
Sudden confusion means the brain is being upset by something acting on it now: infection anywhere in the body (urine and chest infections are classic, especially in older people), new medicines or dose changes, dehydration, low sodium, low blood sugar, stroke, head injury, alcohol withdrawal or poisoning.[4] That is why delirium is treated as an emergency: the cause needs finding today, and most causes are treatable.[1]
Two patterns are easy to miss. Delirium fluctuates, so a person can seem almost normal at lunchtime and lost by evening; the fluctuation is part of the condition, not reassurance. And not all delirium is agitated: hypoactive delirium makes people quiet, drowsy and withdrawn, which families often read as tiredness or low mood.[4] A person who is suddenly "not themselves", vague, unable to follow conversation or drifting off mid-sentence deserves the same urgency as one who is visibly distressed.[1]
Is it delirium, dementia or something else?
Speed is the sharpest separator. Delirium arrives over hours or days, fluctuates, and disturbs attention first: the person cannot focus or follow. Dementia builds over months or years, with memory for recent events usually failing first while attention holds early on. Delirium is usually reversible once its cause is treated; dementia progresses slowly. The two also combine, because dementia makes the brain more vulnerable to delirium, which is why a sudden change in someone with dementia goes to emergency care, not to a booking calendar.[1][3]
A third pattern matters and is genuinely hopeful: low mood can convincingly mimic memory failure. Depression blunts concentration, so information never lands properly in the first place, and people describe forgetting when the real problem is attention. Poor sleep and chronic stress do the same. These are treatable, and improvement with treatment is itself diagnostic; the depression page explains the assessment, and disturbed sleep has its own page covering insomnia and its treatment.
Gradual memory change and the memory-clinic pathway
When thinking has genuinely been slipping over months (repeating questions, losing the thread of plots and conversations, getting lost on familiar routes, struggling with bills and gadgets that used to be easy), the pathway is structured, and an online consultation can start it properly. First, a careful history, ideally with a family member who has watched the change. Second, exclusion of reversible contributors: blood tests for thyroid function, vitamin B12 and folate, blood sugar, kidney and liver function, directed to a laboratory near you, plus a medication review, because sedating and anticholinergic medicines quietly fog cognition.[2] Third, referral to a memory clinic or neurology service for formal cognitive testing and brain imaging, which is where diagnosis actually happens.[2]
Going early is worth it, and not only for the minority whose cause turns out reversible. Early assessment gives the clearest baseline for tracking change, the widest treatment options, and time to plan while the person themselves can lead the planning: finances, driving, wishes.[3] The kind but honest conversation about driving belongs here too: the doctor explains what the diagnosis means for driving, and raising it early keeps the choice in the family’s hands rather than an emergency’s.
Where each confusion pattern should be assessed
Swipe sideways to compare →
| Presentation | Likely first step | Suitable for online care? | When referral or in-person care is needed |
|---|---|---|---|
| Confusion arriving over hours or days, at any age | Emergency assessment for delirium | No | Call 112 now[1] |
| Sudden change in someone who already has dementia | Emergency or same-day in-person assessment | No | Delirium on top of dementia is still an emergency |
| New fogginess after a medicine change | Online medication review with the full prescription list | Often yes | Severe drowsiness or worsening: same-day in-person care |
| Memory slipping gradually over months | Online history with family, blood tests directed, memory-clinic referral | Yes, for assessment and referral | Formal diagnosis needs in-person cognitive testing and imaging[2] |
| Poor concentration with low mood, stress or broken sleep | Online mental health and sleep assessment | Usually yes | If memory keeps declining despite mood and sleep improving |
No emergency features, but you are still worried? A doctor can tell you in one consultation.
See available times →What the doctor checks in an online confusion consultation
Bring a family member if you can, and the medicine boxes; both are genuinely useful. The doctor will typically work through:
- The timeline, precisely: when was the last time they managed the bills, the drive to the coast, the family recipe; anchoring change to real events separates months from days, which is the whole game.
- Attention or memory: whether the person loses focus mid-sentence (points to delirium or mood) or loses recent events while following conversation well (points to memory decline).
- The medication list: every prescription, pharmacy purchase and supplement, looking hard at sedatives, strong painkillers, bladder medicines and older antihistamines, which are common reversible foggers.[2]
- Alcohol, honestly: quantity, pattern, and any recent sudden stops.
- Mood and sleep: screening for depression and for sleep problems, the two great mimics of memory failure.
- Physical clues: recent infections, falls, head knocks, weight loss, incontinence, walking changes, tremor.
- Function and safety at home: cooking, the cooker itself, wandering, driving, money; asked practically, to build a safety picture rather than a judgement.
- What the family has noticed: often the most sensitive instrument in the room, and treated that way.
One limit is stated plainly: no video call can diagnose dementia. Diagnosis needs in-person cognitive testing and usually brain imaging. What the consultation delivers is the correct next step, taken without months of waiting and wondering.
Treatment options for confusion
What you can do at home
For gradual change while assessment is underway: keep routines steady and visible (one calendar, one list, one place for keys), get hearing and vision checked and corrected because both masquerade as cognitive decline, keep blood pressure and diabetes well managed, cut alcohol, protect sleep, and keep the person moving and socially connected, which supports thinking better than any supplement. For safety: a cooker that switches itself off, medicines in a dosette box, and important documents sorted while it is easy. If several people in the household are foggy, headachy or unusually tired at once, and it lifts away from home, check your carbon monoxide alarm and get the boiler checked; it is rare, reversible and missed.
Medication honesty
There is no prescription that fixes confusion, and the online role is often subtraction rather than addition: identifying medicines that may be fogging thinking and agreeing changes with whoever prescribes them. A prescription is never issued without a consultation, and what can be treated online is the treatable contributors: confirmed thyroid problems, vitamin B12 deficiency, depression, poor sleep. Dementia medicines are started by specialists after formal diagnosis, not through a video call.[2] Sedatives make confusion worse, not better, and are not prescribed online.
When confusion is assessed online, and when you need in-person care
Assessed online: gradual memory and thinking changes, with family involvement welcomed; brain fog tied to low mood, stress, poor sleep or menopause; medication-related fogginess; and follow-up while blood tests and referrals progress, so nobody is left holding the worry alone.
In-person care: anything sudden goes to 112 or same-day emergency care, including when it emerges mid-consultation; gradual decline with a completed work-up goes to a memory clinic or neurology for formal testing; rapid progression over weeks, confusion in someone under 65, or confusion with new neurological signs (weakness, walking or speech changes) goes promptly to specialist care; and alcohol-related cognitive problems go to local services where supervised treatment and vitamin support are available. When stress or burnout is the real driver of a foggy head, the doctor treats that honestly instead of labelling it a memory problem.
How Mobi Doctor works
- Book a time that suits you: open daily 7am–11pm CET. You can see a doctor over video, usually within 15 minutes. No subscription, exact price up front.
- Speak to a licensed doctor about confusion: a private video call from anywhere in Europe; family members can join, and often should, to fill in the story.
- Leave with a clear next step: tests directed locally, a referral letter, or treatment for a reversible cause; prescriptions only when right; if your doctor decides you need to be seen in person, you get a full refund.
No sign-up needed
Confusion can have more than one cause. Tick every symptom you have to see each condition page that mentions it. It finds the right page, not a diagnosis: a doctor gives you that on a video call. If you have an emergency sign listed on this page, call 112 instead.
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Not sure this is the right page? Look up any symptom in the full symptom checker, or book and describe it to a doctor.
Frequently asked questions about confusion
What is confusion, medically?
Confusion means thinking, attention or memory that is not working as it should: not knowing the day or place, losing the thread of a conversation, rambling, or being unable to focus. Doctors split it by speed. Confusion that arrives over hours or days is delirium, an emergency with a treatable cause; confusion that creeps in over months points to dementia, depression, medicines or another slow cause.
What should I do right now if someone is suddenly confused?
Treat sudden confusion as an emergency. Call 112 if there are stroke signs, fever, a head injury, diabetes, drowsiness or you cannot rouse them properly; otherwise get them to emergency care without delay. Sudden confusion is delirium until proven otherwise, its causes are usually treatable, and the earlier the cause is found the better the recovery.
What are the signs of delirium?
Delirium shows as confusion that came on over hours or days and fluctuates, often worse at night: poor attention, rambling or muddled speech, not knowing where they are, seeing things that are not there, and either agitation or an unusual quietness and drowsiness. The quiet form is missed most often, so a relative who seems withdrawn and sleepy after a change should raise the same alarm as one who is agitated.
What causes confusion in older people?
In older people confusion is most often triggered by infection (a urine or chest infection is the classic cause), a new medicine or dose change, dehydration, constipation, pain, low sodium, low blood sugar, a stroke or a fall with head injury. An ageing brain has less reserve, so a problem that would barely register at 40 can produce marked confusion at 80.
Can a urine infection or dehydration really cause confusion?
Yes. In older people a urine infection or dehydration is one of the commonest causes of sudden confusion, sometimes with no fever and no bladder symptoms at all. The confusion is delirium, not dementia, and it usually clears over days once the infection is treated and fluids are restored, which is why new confusion in an older relative needs a medical assessment without delay.
Is confusion always dementia?
No, confusion is not always dementia. Sudden confusion is delirium, a treatable emergency with causes like infection, medicines or low blood sugar. Gradual fogginess can come from thyroid problems, vitamin B12 deficiency, depression, poor sleep, alcohol or medication side effects, all of them treatable. Dementia is one cause of slow change among several, and it is diagnosed only after those are excluded.
Can an online doctor diagnose dementia?
No, an online doctor cannot diagnose dementia, and any service claiming to should be avoided. Dementia diagnosis needs in-person cognitive testing and usually brain imaging. What an online doctor can genuinely do about confusion is take a proper history with your family, order the blood tests that exclude reversible causes, and start the memory-clinic referral.
Can medicines cause confusion?
Yes, medicines commonly cause confusion, and it is one of the most fixable causes. Sedatives, sleeping tablets, strong painkillers, some bladder medicines and older antihistamines are frequent culprits, alone or in combination, especially in older people. Never stop medicines abruptly; bring the boxes to the consultation and the doctor reviews what can be changed.
How long does confusion last after an infection, surgery or a stroke?
Delirium usually clears within days to a couple of weeks once its cause is treated, but in older people, after major surgery or in someone who already has dementia, confusion can take weeks or occasionally months to settle fully. Confusion after a stroke follows the stroke's own recovery and needs the stroke team's assessment rather than a wait-and-see approach.
How can confusion be prevented in an older relative?
Confusion from delirium is often preventable: keep them drinking enough, treat infections and constipation early, review medicines regularly with a doctor, make sure glasses and hearing aids are worn, keep a clock and calendar in view, protect night-time sleep, keep them moving and avoid unnecessary sedatives. During a hospital stay, a familiar face and the same routines reduce the risk markedly.
What can we do at home while a gradual memory change is being assessed?
For gradual confusion, keep routines steady and visible: one calendar, one list, one place for keys. Get hearing and vision checked and corrected, keep blood pressure and diabetes well managed, cut alcohol, protect sleep, and keep the person active and socially connected, which supports thinking better than any supplement. For safety, check the cooker, medicines and driving.
Is confusion near the end of life different?
In the last weeks of life, confusion is common and usually comes from the illness itself, dehydration, infection or the medicines needed for comfort. It is managed by the palliative care team, who look for reversible causes, adjust medicines and support the family; it is not a reason to call an online doctor, and a sudden change still deserves a call to the team caring for them.
- Delirium: prevention, diagnosis and management in hospital and long-term care (CG103), NICE, National Institute for Health and Care Excellence, 2010 (updated 2023).
- Dementia: assessment, management and support for people living with dementia and their carers (NG97), NICE, National Institute for Health and Care Excellence, 2018.
- Dementia: fact sheet, WHO, World Health Organization, 2023.
- Delirium, NICE Clinical Knowledge Summaries, revised 2024.
- Delirium information and resources, EDA, European Delirium Association, 2025.
- Sudden confusion (delirium), NHS, National Health Service (UK), accessed October 2026.
This page is for information only and is not a substitute for a medical consultation. Guideline links are provided for transparency; treatment decisions are made with your doctor.
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