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Nursing Field Notes / Neuro · The high-yield comparison · Med-Surg
🧠 NEURO SET NG-255 Neuro Overview NG-069 Alzheimer's NG-244 Dementia vs Delirium NG-258 Parkinson's NG-253 MS NG-245 Guillain-Barré

Dementia vs Delirium

Gradual and permanent · vs · SUDDEN, fluctuating and REVERSIBLE

NG-244 NEURO · COMPARISON ADHD-friendly visual edition

This is one of the highest-yield comparisons in the whole of med-surg, and it is a patient-safety question, not a trivia question. Delirium is an acute medical emergency with a cause you can find and fix — infection (especially a UTI in an older adult), hypoxia, drugs, electrolytes, pain. Dementia is slow, structural and permanent. The trap the exam sets, and the one that hurts real patients, is the sudden change in a person who already has dementia: that gets worked up as delirium — it is never “just the dementia getting worse”.

📄 Simple Nursing original — opens in Drive →

⚡ DELIRIUM = SUDDENHours to days · fluctuates · attention is impaired · REVERSIBLE if you find the cause.
🐌 DEMENTIA = GRADUALMonths to years · steady · attention intact early · irreversible.
🦠 THINK UTI FIRSTNew confusion in an older adult → infection until proven otherwise. Fever may be absent.
🚨 PRIORITY ACTIONASSESS THE CLIENT. Vitals, SpO₂, glucose, urine, med review — before you sedate, restrain or reassure anyone.
⏱️

ONSET AND COURSE

STEP 1

When did it start, and does it fluctuate? These two questions answer most exam items.

FIGURE 1 · ONSET AND COURSE — the single best way to tell them apartCognitive function on the vertical axis, time on the horizontal · read the panels ① → ③① DEMENTIA — gradual, over MONTHS TO YEARS · never returns to baselineNORMALSEVEREimpair.TIME → months to yearsSlow, steady, downhillIrreversible② DELIRIUM — SUDDEN (hours to days) · FLUCTUATES · returns to baseline once the cause is fixedNORMALSEVEREimpair.TIME → hours to daysABRUPT onset — you canoften name the DAYFLUCTUATES: lucid one hour, confused the next.Typically worse at night.CAUSE TREATED→ back to baseline③ THE TRAP — DELIRIUM on top of DEMENTIA · a sudden change in someone with dementia is NOT “just the dementia”NORMALSEVEREimpair.TIME →Known dementia — slow declineSUDDEN worsening today→ work it up as DELIRIUMTreat the cause and they comeback — to their dementia baseline,not to “normal”LINE COLORdementiadelirium

If a family member can tell you the DAY it started, you are looking at delirium. If nobody can name a day and it has been creeping for a year, you are looking at dementia.

⭐ THE comparison table — learn this row by row

DELIRIUMDEMENTIA
OnsetACUTE — hours to days. You can often name the day. GRADUAL — months to years. Nobody can name a day.
CourseFLUCTUATES hour to hour · lucid intervals · worse at night Steady and slowly progressive
AttentionIMPAIRED — this is the core feature. Cannot hold a thread. Intact until late
Level of consciousnessALTERED — drowsy or hyper-alert Normal — alert until late stages
DurationHours to days, sometimes weeksYears, until death
HallucinationsCommon, often visual and frightening Uncommon until late
SpeechRambling, incoherent, jumps around Word-finding difficulty, then loss of vocabulary
Sleep–wake cycleDisrupted / reversedFragmented but recognizable
CauseAn identifiable physiological insult — go and find it Structural brain disease (Alzheimer's, vascular, Lewy body, frontotemporal)
Reversible?YES — treat the causeNO
Priority actionASSESS THE CLIENT and find the cause Safety, routine, redirection, caregiver support
🧠 De-L-irium = Limited and Lasts a Little while. De-M-entia = daMage, and it's perManent.
FIGURE 4 · THE SAME SIX QUESTIONS, ASKED OF BOTH PATIENTSRead the rows straight across ① ↔ ② · ATTENTION and ONSET are the two that decide it① DEMENTIA at the bedsideMonths of gradual change② DELIRIUM at the bedsideIt started yesterday“Is it 1962? Where'sMother?” — but says itcalmly, and stays with youthrough the conversation.“There are bugs on thewall!” — pulling at the IV,cannot finish a sentence,drifts off mid-answer.👁️ ATTENTIONINTACT early — can hold a conversation⏱️ ONSETMonths to years · nobody can name the day🌊 COURSEStable through the day, slowly worse over months😴 ALERTNESSNormal — awake and alert👻 HALLUCINATIONSUncommon until late🔁 REVERSIBLE?NO — this is permanent damage👁️ ATTENTIONIMPAIRED — this is the core feature⏱️ ONSETHours to days · family can name the day🌊 COURSEFLUCTUATES hour to hour · worse at night😴 ALERTNESSAltered — drowsy OR hypervigilant👻 HALLUCINATIONSCommon — often visual, often frightening🔁 REVERSIBLE?YES — if you find and treat the cause

Two questions do most of the work: “When did this start?” and “Can they hold their attention on me?” Everything else is confirmation.

⭐ How to actually test attention in 30 seconds

  • “Say the months of the year backwards, starting with December.”
  • “Say the days of the week backwards.”
  • Digit span: repeat 5 numbers forwards, 3 backwards.
  • Watch for: losing the thread mid-sentence, being distracted by anything that moves, needing the question repeated.

Inattention is the single most useful bedside finding for delirium. A person with early dementia can usually still stay with you; a delirious person cannot.

🧠 Delirium can't pay attention. Dementia can't remember.
🔍

DELIRIUM — FIND THE CAUSE

STEP 2

Delirium is a symptom of something else. Your job is to go and find the something else.

FIGURE 2 · DELIRIUM ALWAYS HAS A CAUSE — go and find itRadial diagram · the center is the patient, each arrow points OUT to something you can test for and treat????ACUTE CONFUSION🦠 INFECTIONUTI (most common in older adults) ·pneumonia · sepsis#1 CAUSE🫁 HYPOXIALow SpO₂ · pneumonia · heart failure ·PE💊 DRUGSOpioids · benzodiazepines ·anticholinergics · polypharmacy ·alcohol withdrawal🧂 ELECTROLYTESLow sodium · low or high glucose ·dehydration · uremia😖 PAINUntreated pain · a full bladder ·constipation🛏️ ENVIRONMENTNew room · no glasses or hearing aids ·no sleep · no daylight · restraintsDELIRIUM = Drugs · Electrolytes · Lack of drugs (withdrawal) · Infection · Reduced sensory input · Intracranial · Urinary/faecal retention · Myocardial + pulmonary

Every arrow points to something you can measure or review in the next twenty minutes. Delirium without a cause simply means the cause has not been found yet.

🚨 The single highest-yield trap on this whole page

A resident with known dementia is suddenly much more confused today.

Work it up as DELIRIUM. Do NOT chart “dementia worsening”. Dementia does not change overnight. A sudden change on top of dementia is an acute medical problem — most often a urinary tract infection, pneumonia, dehydration, a new medication, urinary retention, constipation or uncontrolled pain.

People with dementia are the group at highest risk of developing delirium — and the group in whom it is missed most often, because everyone assumes the confusion is baseline.

🧠 “Sudden = search.” Sudden change in an older adult means go looking, every time.
FIGURE 3 · UTI IN AN OLDER ADULT — confusion may be the ONLY symptomRead LEFT (what the textbook says) → RIGHT (what actually happens in the frail older adult)① UNDER 65 with a UTIThe textbook picture② OLDER ADULT with a UTIThe picture that gets missed????confusion, not burning🔥 Fever🚻 Burning · urgency · frequency🩸 Cloudy or bloody urine😖 Suprapubic or flank pain🧠 Thinking stays NORMAL🧠 NEW CONFUSION — often the ONLY sign😴 Sudden lethargy, or new agitation🤕 A new fall · “gone off their legs”🍽️ Poor appetite · new incontinence🌡️ Fever may be ABSENT or low-gradeAny older adult with SUDDEN confusion gets: vital signs · SpO₂ · blood glucose · a urine sample · a medication review.

In frail older adults the immune and inflammatory response is blunted, so the classic burning and fever may never appear — the brain complains before the bladder does.

FIGURE 5 · SUDDEN CONFUSION? — these are the numbers you go and getRead LEFT → RIGHT · every one of these is a reversible cause you can find in minutes101.4 °F88%54mg/dL135–145Na⁺ 123LOWHIGHcloudy · foul🌡️ TEMPERATUREAny temp over100.3 °F / 38 °C— and remember fevermay be ABSENT🫁 OXYGEN (SpO₂)Below 92% (or belowthe patient's usual)= hypoxia untilproven otherwise🩸 BLOOD GLUCOSETypical adult fasting70–110 mg/dLLow glucose causesconfusion FAST🧂 SERUM SODIUMTypical adult 135–145 mEq/LLow sodium is aclassic, easily-missedcause🧫 URINECulture + urinalysis.Positive nitrites orleukocytes with newconfusion = treat

This is the exam's favorite “select all that apply”: which findings could be causing this delirium? Temperature, SpO₂, glucose, sodium and a positive urine culture are all yes. The ranges shown are typical adult reference ranges and vary between laboratories.

🧪 The lab and vital-sign values worth memorizing

  • Temperature — a documented fever over 100.3 °F (38 °C) plus new confusion is infection until proven otherwise. In older adults fever may be absent.
  • SpO₂ — under 92% (or a drop from the patient's normal) = hypoxia. Hypoxia makes people confused before it makes them breathless.
  • Blood glucose — typical adult fasting reference range 70–110 mg/dL. Hypoglycemia causes confusion within minutes and is fixed within minutes.
  • Serum sodium — typical adult reference range 135–145 mEq/L. A sodium of 123 is a classic, easily-missed cause.
  • Urinalysis + culture — positive nitrites/leukocyte esterase with new confusion.
  • Reference ranges vary between laboratories — these are typical adult values; always use the range your facility reports.
🧠 The classic select-all: positive urine culture with 101 °F · sodium 123 · SpO₂ 82% are all causes. Glucose 120 is not low enough to explain the confusion — it is the distractor.
FIGURE 6 · THE TWO FACES OF DELIRIUM — and the one that gets missedBoth patients are delirious · read LEFT (loud) → RIGHT (quiet) · the quiet one is more common and does worse① HYPERACTIVE deliriumThe one everybody notices② HYPOACTIVE deliriumMORE COMMON · most often MISSEDpulling at the IVzzzquiet · withdrawn · “no trouble at all”Agitated, restless, shoutingPulls at IVs, lines and dressingsTries to climb out of bedHallucinations and paranoiaGets noticed — and often gets sedatedQuiet, sleepy, slow to answerWithdrawn, apathetic, does not eatLooks like depression or “just tired”Still INATTENTIVE — test it, don't assumeMissed most often · WORSE outcomesA quiet patient is not automatically a settled patient. Test attention: “Say the months of the year backwards from December.”

Hypoactive delirium is the more common form and the one nobody calls about, because a quiet patient makes no noise. It carries a worse prognosis than the agitated form.

🚨 Priority action — in order

1
ASSESS THE CLIENT. Airway, breathing, circulation, vital signs, SpO₂, glucose, pain, bladder, last bowel movement, level of consciousness
↓
2
Review the medications — what is new, what was stopped, what was given in the last 24 hours
↓
3
Get the specimens — urinalysis and culture, bloods, and notify the provider
↓
4
Treat the cause and support the patient while it resolves

Never sedate or restrain a newly confused patient before assessing them. Sedation removes your ability to monitor the very thing you are worried about, and restraints make delirium worse.

🧠 If an option starts with “assess”, “obtain vital signs” or “check the client”, it is almost always the answer.

✅ Non-drug management of delirium — do all of this

  • Give the senses back: glasses ON, hearing aids IN, dentures in. Sensory deprivation feeds delirium.
  • Re-orient gently and often — clock, calendar, name badge, say what day it is. (This IS appropriate in delirium; it is not appropriate in advanced dementia.)
  • Protect sleep: lights on and curtains open by day, dark and quiet at night, cluster care so you are not waking them hourly.
  • Mobilize early and get them out of bed; treat pain, constipation and retention.
  • Hydration and nutrition; remove unnecessary lines and catheters (they are both a cause and a hazard).
  • Familiar faces — encourage family to stay; keep staff consistent.
🧠 Glasses · hearing aids · clock · daylight · pain · pee · poo. The delirium checklist.
🧠

DEMENTIA — LIVE WITH IT SAFELY

STEP 3

Irreversible damage. Care is about safety, routine and how you speak.

🧠 Dementia is an umbrella, not a diagnosis

  • Alzheimer's disease — the most common (≈60–80%). Memory first. Plaques and tangles. Full page here.
  • Vascular dementia — from strokes or small-vessel disease. Often step-wise decline rather than smooth.
  • Lewy body dementia — visual hallucinations, fluctuating cognition and parkinsonism. Extremely sensitive to antipsychotics.
  • Frontotemporal dementia — personality and behavior change first, memory later, often younger onset.
  • Parkinson's disease dementia — see NG-258.
  • Also: Huntington's disease and traumatic brain injury cause irreversible brain damage.
🧠 DeMentia = DaMage. Many roads, one destination.

💬 Managing the person with dementia — distraction, not correction

In end-stage dementia there is too much damage for the person to hold on to reality. Insisting on reality only produces anxiety and aggression, so interventions revolve around distraction.

  1. 1. Acknowledge and discuss the feeling — “You're worried about him.”
  2. 2. Redirect with a new activity — a crossword, folding towels, photographs, a walk.
  3. 3. Do NOT present reality or rationalise.

Encourage them to talk about the “mixed-up” feelings; place personal items and photographs at the bedside; provide a manual activity so a restraint is never needed.

SAME 3 STEPS NG-069 Alzheimer's — drawn out in full there.

⭐ Re-orient or redirect? The rule that decides

DELIRIUM → RE-ORIENTThe confusion is temporary and the brain can take the information in. Clock, calendar, “It's Tuesday morning, you're in the hospital, I'm your nurse.”
ADVANCED DEMENTIA → REDIRECTThe brain cannot store the correction. Repeating reality just re-inflicts the loss. Acknowledge the feeling and change the activity.
🧠 Delirium: bring them BACK. Dementia: take them SOMEWHERE ELSE.

🧪 What both have in common

  • Both raise the risk of falls, aspiration, dehydration and pressure injury.
  • Both need a calm, familiar, well-lit environment and a predictable routine.
  • Both are made worse by restraints, tethers (catheters, telemetry leads, IV poles), interrupted sleep and untreated pain.
  • Both need the family involved — they are your best source of what “normal” looks like.
  • Neither is a reason to talk to the patient like a child.
🧠 Ask the family: “Is this how they usually are?” That one question separates baseline from acute change better than any tool.

⭐ CAM — the 4-step delirium screen

The Confusion Assessment Method needs 1 AND 2, plus 3 OR 4:

  1. 1 · Acute onset and fluctuating course — is this a change from baseline, and does it come and go?
  2. 2 · Inattention — cannot hold a thread, easily distracted.
  3. 3 · Disorganized thinking — rambling, illogical, jumping between ideas.
  4. 4 · Altered level of consciousness — anything other than alert (drowsy, stuporous, or hypervigilant).
🧠 1 and 2, plus 3 or 4. Attention is compulsory — you cannot have delirium with normal attention.

🧪 Who is set up for delirium before anything even happens

PREDISPOSING (the loaded gun)Age over 65 · existing dementia or cognitive impairment · poor vision or hearing · frailty and immobility · polypharmacy · dehydration · previous delirium · alcohol use
PRECIPITATING (the trigger)Infection · surgery and anesthesia · a new drug · hypoxia · pain · dehydration · retention or constipation · a new environment · sleep deprivation · restraints

The more loaded the gun, the smaller the trigger needed. A frail 88-year-old can become delirious from constipation alone.

🧠 Loaded gun + small trigger. That is why the frailest patients look the sickest from the smallest problems.

🏥 Post-operative delirium — expect it and prevent it

  • Very common in older adults after hip fracture and after cardiac surgery.
  • Usual culprits: anesthetic and opioid load, pain, hypoxia, blood loss and anemia, electrolyte shifts, urinary retention, a new environment and disrupted sleep.
  • Treat pain properly. Under-treated pain causes more delirium than well-managed opioids do — but avoid the high-risk drugs (benzodiazepines, anticholinergics, meperidine).
  • Get them up and moving early, remove the catheter as soon as possible, restore the glasses and hearing aids in recovery.
  • Screen every shift with CAM in high-risk patients.
🧠 Pain, pee, pills, pO₂. Four Ps behind most post-op confusion.

✅ Prevention beats treatment — the non-drug bundle

  • Orientation: clock, calendar, familiar objects, staff who introduce themselves each time.
  • Sensory: glasses on, hearing aids in and working, adequate lighting.
  • Sleep: dark and quiet at night, no unnecessary observations, no caffeine in the evening.
  • Mobility: out of bed, walking every day, physiotherapy.
  • Hydration and nutrition: fluids in reach, help with meals, dentures in.
  • De-tether: remove catheters, telemetry and IV lines as soon as they are not needed.

These measures reduce the incidence of delirium — they are not just comfort measures.

🧠 Sight · Sound · Sleep · Steps · Sips. Five Ss and delirium halves.

💊 Medication is the LAST resort in delirium

  • First: find and treat the cause, and use every non-drug measure.
  • Medication is only for severe agitation that puts the patient or others at risk — never for the convenience of staff.
  • If used: lowest dose, shortest time, and reassess constantly.
  • Benzodiazepines usually make delirium worse — the exception is delirium from alcohol or benzodiazepine withdrawal, where they are the treatment.
  • Antipsychotics carry an increased mortality risk in older adults with dementia; if a person may have Lewy body dementia, they can cause a severe reaction.
  • Review every drug on the chart: which one started this?

Never treat agitation with sedation before you have assessed for a cause.

🧠 Sedation hides the very thing you are trying to find.

🚨 Depression — the third one in the differential

DELIRIUMDEMENTIADEPRESSION
OnsetHours–daysMonths–yearsWeeks–months
AttentionImpairedIntact earlyUsually intact, poor effort
Memory complaintCannot register anything Denies or hides the problemComplains loudly about memory
AnswersRambling, incoherentConfabulates, near-misses “I don't know” — gives up quickly
MoodFluctuates with the deliriumVariable, often flat Persistently low, anhedonia
Reversible?YesNoYes — it is treatable

Pseudodementia is depression in an older adult that looks like dementia. It is worth catching, because unlike dementia it gets better with treatment.

🧠 Dementia hides the deficit. Depression advertises it. Delirium can't even engage with the question.
⚖️

TELL THEM APART IN 10 SECONDS

STEP 4

If you remember nothing else on this page, remember these four lines.

⭐ The four-question sort

1 · When did it start?Hours/days = delirium. Months/years = dementia.
2 · Does it come and go?Fluctuating = delirium. Steady = dementia.
3 · Can they pay attention?No = delirium. Yes (early) = dementia.
4 · Is there a cause you can test for?Almost always with delirium. Go and test for it.
🧠 WHEN · WAVY · WATCHING · WHY. Four Ws and you have the answer.

✅ Documentation that protects the patient

Weak: “Patient confused as usual.”

Strong: “Baseline per daughter: oriented to person and place, walks to the bathroom alone. Today: not oriented to place, cannot say the months backwards, drowsy, temp 100.8 °F, urine cloudy. Provider notified 1420, urinalysis sent.”

🧠 Always chart the BASELINE next to today. A change is only visible against something.

❌ Answers that are always wrong here

  • ❌ “Apply restraints so the client doesn't pull the IV.”
  • ❌ “Administer the PRN sedative first, then assess.”
  • ❌ “Document that the dementia is worsening.”
  • ❌ “Reassure the family this is normal for her age.”
  • ❌ “Wait and reassess at the end of the shift.”

Confusion is never “normal for age”.

🧠 Assess before you sedate. Always.
⚡ SUDDEN = DELIRIUMHours to days, fluctuating, inattentive, altered alertness. Find the cause and it reverses.
🐌 GRADUAL = DEMENTIAMonths to years, steady, attention intact early, alert. Irreversible damage.
🦠 UTI · HYPOXIA · DRUGSPlus electrolytes, glucose, pain, retention, constipation, withdrawal. Fever may be ABSENT in the older adult.
🚨 ASSESS FIRSTVitals · SpO₂ · glucose · urine · med review. Never sedate or restrain before assessing.
🪤 THE TRAPSudden change in someone with dementia = work it up as delirium. Never chart “dementia worsening”.
🧭 ORIENT vs REDIRECTDelirium → re-orient (they can take it in). Advanced dementia → acknowledge the feeling and redirect.