Delirium and UTIs in older people: signs, causes and what to do

Delirium is a sudden change in someone’s thinking, alertness or behaviour that develops over hours or days, and in older people it is often triggered by an infection, dehydration, constipation, pain or a new medicine. Unlike dementia it is usually temporary, but it is a medical emergency: the NHS says to call 999 or go to A&E if someone suddenly becomes confused. A urine infection is one possible cause, but national guidance warns against blaming every confused episode on a UTI.

In short

• NICE lists four main risk factors for delirium: being 65 or older, having dementia or cognitive impairment, a current hip fracture, and severe illness.
• The NHS says to call 999 if someone with a suspected UTI is confused, drowsy or has difficulty speaking. If you are unsure, call 111.
• UK Health Security Agency (UKHSA) guidance for adults over 65 says “Do not perform urine dipsticks” because results become less reliable with age.
• By 80, about half of older adults living in care homes can have bacteria in their urine without any infection, according to UKHSA. Antibiotics do not help this and can cause harm.
• “Quiet” (hypoactive) delirium, where someone becomes withdrawn and sleepy, is the type most often missed.
• Delirium can last days or weeks. Avoid making permanent care decisions, such as a care home move, while it is still clearing.

Delirium or dementia? How to tell the difference

The biggest clue is speed. Dementia changes over months and years. Delirium changes over hours or days, and often fluctuates, with someone lucid in the morning and very confused by evening. People with dementia are more likely to develop delirium, and the two can exist together, which is why families are often the first to notice that “this is not like Mum”.

The three types

• Hyperactive delirium: restless, agitated, trying to get out of bed, pulling at drips, sometimes seeing things that are not there.
• Hypoactive delirium: withdrawn, sleepy, slow to answer, not eating or drinking. NICE warns this is often missed because the person seems “quiet” rather than unwell.
• Mixed: swings between the two.

Common causes

Delirium usually has more than one cause. UKHSA’s guidance for clinicians uses the memory aid PINCH ME to check them: Pain, other INfection, Nutrition, Constipation, Hydration, Medication and Environment change. In everyday terms, look for:

• infections, including chest infections, skin infections and urine infections;
• not drinking enough, especially in hot weather or when someone is afraid of incontinence;
• constipation or urinary retention;
• new or changed medicines, including some sleeping tablets, strong painkillers and bladder medicines;
• pain, for example after a fall;
• a move to hospital, a care home or respite, poor sleep, or missing glasses and hearing aids.

Stroke, low blood sugar in diabetes, head injury and alcohol withdrawal can also cause sudden confusion, which is why medical assessment matters rather than guessing.

UTIs in older people: the myths

Myth 1: confusion means a urine infection

UTIs are a common cause of sudden confusion in older people and people with dementia, and the NHS lists agitation or confusion among UTI symptoms in frail older people. But they are not the only cause, and treating a “UTI” that is not there can mean the real problem, such as a chest infection, constipation or a medicine side effect, is missed. UKHSA’s decision tool says that if the only signs are fever with delirium, other infections should be excluded before treating for a UTI.

Myth 2: a dipstick test will tell you

For adults over 65, UKHSA guidance is clear: “Do not perform urine dipsticks.” As people age, more of them carry bacteria in the urine without being ill, known as asymptomatic bacteriuria. By 80, about half of care home residents may have it. A dipstick will often be positive whatever the cause of the confusion. The same advice applies to people with long-term catheters. Instead, clinicians look at symptoms and send a urine sample to the laboratory before starting antibiotics, because resistance is more common in older adults.

What clinicians look for instead

Under the UKHSA tool, signs that point towards a UTI in someone over 65 include new pain when passing urine, or two or more of: a fever, new frequency or urgency, new incontinence, new or worsening delirium or decline in daily functioning, new pain above the pubic bone, or visible blood in the urine. Signs of a kidney infection or sepsis, such as back or loin pain, shivering, vomiting, or a very high or low temperature, need urgent assessment.

Myth 3: cranberry juice and forcing fluids fix it

Drinking enough matters, but there is no need to push excessive amounts. The NHS suggests drinking enough to pass pale urine regularly during the day and limiting drinks that can irritate the bladder, such as fruit juice, coffee and alcohol.

Hydration: practical tips

• Offer small drinks often rather than large glasses; leave a drink within reach at all times.
• Use a cup your parent can manage, such as a lighter mug or a two-handled beaker.
• Count foods with high water content: soup, jelly, yoghurt, fruit and ice lollies.
• Reassure anyone who restricts drinks for fear of accidents; good continence products are safer than dehydration.
• Keep an eye on urine colour and on drinks left untouched. Paid carers can record fluid intake if you ask.

When to call 999, 111 or the GP

While you wait, stay with the person, speak calmly in short sentences, avoid lots of questions, and bring their medicines and glasses to hospital.

Delirium after hospital and discharge into care

Delirium often starts or gets worse in hospital, and it can take days or weeks to clear after discharge. NICE says families should be told that delirium is common and usually temporary, and encouraged to report any sudden changes. You can help by visiting, bringing familiar objects, glasses and hearing aids, and telling staff what is normal for your parent.

Be cautious about decisions made while someone is still delirious. Mental capacity is decision-specific and time-specific under the Mental Capacity Act 2005, so a person who cannot decide where to live today may be able to next week. Ask whether a mental capacity assessment was done and when. If a care home placement is proposed straight from hospital, ask whether it is a short-term discharge bed or a permanent move, who is paying, and when needs will be reassessed. Our guides on care after hospital discharge, free short-term care after hospital and reablement explain your options, and what to do about an unsafe discharge covers how to challenge a plan.

A short stay of convalescent care can help someone recover in a calm setting before deciding on longer-term care. If a permanent move does follow, see when it is time for a care home and use the funding checker to see what help may be available.

Preventing delirium in a care home or at home

NICE’s prevention measures translate well to everyday care: keep the same familiar carers where possible, use good lighting and a visible clock and calendar, make sure glasses and hearing aids are in use, encourage drinking and regular bowels, keep people moving, manage pain and protect night-time sleep. When choosing a home, ask how staff spot a sudden change and how they record fluids. Our care home visiting questions include these.

Scotland, Wales and Northern Ireland

The clinical picture is the same. NICE and UKHSA guidance is written for England and widely followed elsewhere; Scotland has its own SIGN guidance on delirium. NHS 111 runs in England, Scotland and Wales. In Northern Ireland, contact your GP or out-of-hours service, or call 999 in an emergency.

Frequently asked questions

Can a UTI cause sudden confusion in the elderly?

Yes. Urine infections are a common cause of delirium in older people and people with dementia. But many other things cause it too, including chest infections, dehydration, constipation and medicines. The NHS says to call 999 if someone with a suspected UTI becomes confused, drowsy or has difficulty speaking.

Why won’t the GP do a urine dipstick test for my mum?

UKHSA guidance for adults over 65 says not to use urine dipsticks because they become less reliable with age. Many older people carry bacteria in their urine without infection; by 80, about half of care home residents may do so. Clinicians assess symptoms instead and send a sample to the lab.

How long does delirium last in older people?

It varies. Delirium often improves within days once the cause is treated, but in older people and those with dementia it can take weeks to clear fully. NICE describes delirium as common and usually temporary. Tell the GP if confusion has not improved or gets worse after discharge.

What is the difference between delirium and dementia?

Delirium starts suddenly, over hours or days, fluctuates and usually improves once the cause is treated. Dementia develops gradually over months or years and is progressive. Someone with dementia can also get delirium, so any sudden change in a person with dementia should be treated as possible delirium.

Should I call 111 or 999 for sudden confusion?

Call 999 or go to A&E if someone suddenly becomes confused, very drowsy or has difficulty speaking, as the NHS advises. Call 111 or ask for an urgent GP appointment for a suspected UTI in someone aged 65 or over without those warning signs, or if you are unsure.

Can delirium affect a decision to move into a care home?

It can. Under the Mental Capacity Act 2005, capacity is judged for each decision at the time it is made. Someone who is delirious may lack capacity temporarily. Where possible, delay permanent decisions until the delirium has cleared, and ask for short-term or discharge-to-assess care in the meantime.

Sources

• NHS: Confusion
• NHS: Urinary tract infections (UTIs)
• UKHSA: Urinary tract infection, diagnostic tools for primary care
• UKHSA: Diagnosis of urinary tract infections, quick reference tools
• NICE CG103: Delirium, prevention, diagnosis and management
• Mental Capacity Act 2005

General information, not legal or financial advice. Figures for 2026/27, checked October 2026.

Reviewed by The Care Panel team on 29 October 2026. This guide is general information about care in England, not legal, medical or financial advice. Rules and rates change; check with your council or an adviser before making decisions.