Delirium vs dementia: when sudden confusion is an emergency
Delirium vs dementia: delirium comes on in hours or days and needs a doctor today. How to tell, what to tell hospital staff, and how to help him recover.
Delirium vs dementia comes down to speed. Dementia changes slowly, over months and years. Delirium comes on over hours or days, makes it hard to pay attention or stay awake, and often gets better and worse within the same day. If your dad has dementia and is suddenly much more confused, sleepy, agitated or seeing things, treat it as a medical problem and call his doctor today. Delirium usually has a cause, like an infection, a new medicine, dehydration or surgery, and many of those causes can be treated.
Families often hear "well, he does have dementia" from someone who met him an hour ago. You're the one who knows his normal.
Delirium vs dementia: how to tell the difference
They can look alike in a single moment. The pattern over time is what gives delirium away. These differences come from MedlinePlus, the National Library of Medicine's health site, which also notes that in delirium alertness swings during the day, often better in the morning and worse at night.
| Delirium | Dementia | |
|---|---|---|
| How it starts | Suddenly, over hours or days | Gradually, over months or years |
| Main problem | Attention and staying alert | Usually memory first |
| How long | Hours to weeks, often gets better | Keeps progressing |
The attention part is the easiest thing to check at home. A dad with plain dementia may not know what year it is, but he can usually look at you and follow a short back-and-forth. In delirium, he drifts off in the middle of a sentence, can't keep his eyes on you, or answers a question you asked five minutes ago.
Having dementia doesn't protect him from delirium. It does the opposite. MedlinePlus lists dementia, older age, surgery and being in a hospital as risk factors. The Alzheimer's Association says people already living with dementia are especially vulnerable, and an episode can speed up their decline. So the question is rarely "which one is it?" It's "is something new happening on top of his dementia?"
The quiet delirium that looks like a bad day
People picture delirium as yelling and pulling at an IV. That's the hyperactive kind. MedlinePlus describes a hypoactive kind too, where the person seems sleepy, tired or depressed, and a mixed kind that switches between the two.
The quiet kind is easy to miss, especially by staff who've never met him. A dad who suddenly sleeps through lunch, barely opens his eyes when you say his name and stops reaching for his coffee isn't just having an off day. If that came on over a day or two, it needs the same urgent call as shouting does. If the withdrawal crept in slowly over months instead, the guide on dementia apathy vs depression is a better fit.
Why sudden change is an urgent call
Delirium usually has a trigger. MedlinePlus lists infections such as urinary tract infections, pneumonia and the flu, medicines including pain medicines and sedatives, surgery and general anesthesia, dehydration, severe pain and serious lack of sleep. Find and treat the cause, and the confusion often lifts.
Pain is one that families miss. The National Institute on Aging notes that people with dementia may not be able to tell you they hurt. Watch for grimacing, moaning, shifting position over and over, trouble sleeping or refusing food, which can mean a sore tooth.
If it's after hours, call the after-hours line or the nurse line on his insurance card. Don't wait until Monday to see if it settles.
What to tell the doctor and hospital staff
Nobody in that building knows his baseline. The National Institute on Aging tells caregivers to help hospital staff understand the person's usual functioning and behavior, because that's what lets them tell dementia apart from delirium. It also says to tell the doctor right away if he seems suddenly worse or different.
Staff hear "he's confused" all day. Give them before and after.
- What he could do last week: dress himself, feed himself, walk to the bathroom, know your name.
- When the change started, and how fast.
- Anything new: a medicine, a fall, a fever, a procedure.
- How to talk with him so he understands, which NIA also recommends you explain.
The Alzheimer's Association adds a few more. Check that his dementia diagnosis is on the chart. Remind staff that he may give wrong answers to their questions, and ask to be included when decisions get made. Tell them about any past bad reactions to medicines and any history of wandering.
Take Denise, whose father went in for a hip repair. On the second night he pulled at his IV and called the nurse by his late wife's name. A doctor told her that was "his dementia." Denise showed him a phone video from the week before, her dad teasing her over breakfast, and asked them to check for delirium. The team brought back his hearing aids, kept the room bright during the day, arranged a sitter at night and reviewed his medicines. By the end of the week he was clearer, though not quite back to where he'd been.
What to say when something's wrong
Short and specific beats polite and vague. NIA warns you may need to repeat the story to each new person.
How to help during a hospital stay
You can't fix delirium yourself, but you can help him come out of it. These tips come from NIA, MedlinePlus and the Alzheimer's Association.
- Have someone familiar with him as much as possible. NIA suggests a family member, friend or paid caregiver. Take shifts. You need sleep too.
- Put his glasses and hearing aids on him. Keep a clock and a calendar where he can see them, and good light in the daytime.
- Protect his sleep. Ask the night nurse what can be done so he gets longer stretches of it.
- Help him eat and drink. NIA says older adults can become undernourished in the hospital. Open the containers, sit with him at meals and offer sips often.
- Get him up if staff say it's safe. Long bed rest weakens muscles and raises the risk of falls.
- Cut the noise. Turn off the TV and lower the phone. Put his street clothes out of sight so they don't make him want to leave.
- Ask what every new medicine is for, and say so if one has made him confused before.
- Ask whether the hospital has a delirium prevention program, such as the Hospital Elder Life Program, often called HELP. The Alzheimer's Association suggests asking for one.
After he comes home
Start on discharge early. NIA suggests asking the discharge planner about home health services and equipment, and expecting to do more care once he's home. The Alzheimer's Association says to make sure the discharge team knows about his dementia. If you don't think you can manage him safely at home, say so to the discharge planner before the papers are signed. The guide on when it's time for memory care can help you think it through.
Expect a slow climb. MedlinePlus says delirium often lasts about a week, and thinking can take several more weeks to get back to normal. The Alzheimer's Association notes that in some people it lingers for months. Keep a short daily note on his sleep, his eating, and how clear he is in the morning versus the evening. Bring it and every pill bottle to the first follow-up.
Questions caregivers ask
Can surgery cause dementia in the elderly?
Confusion after surgery is often delirium, and MedlinePlus lists surgery and general anesthesia among its causes. The Alzheimer's Association says an episode of delirium is linked to a higher risk of later dementia. Researchers don't yet know whether delirium causes that or uncovers disease that was already there. Before a planned operation, ask the surgeon how the anesthesia could affect his thinking.
How long does hospital delirium last?
Often days to about a week once the cause is treated, with several more weeks before thinking settles. In some older adults it lasts months. If he's not improving, or he's getting worse, tell his doctor.
Can a UTI cause sudden confusion in someone with dementia?
Yes. Urinary tract infections are one of the infections MedlinePlus lists as causes of delirium. If he's suddenly more confused, ask his doctor whether he should be checked for an infection. Don't guess and wait.
