Compare conditions

Put any two — or three — conditions side by side, adult or pediatric, to spot the look-alike differences fast, row by row.

Delirium Versus Dementia Versus Psychosis

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In one line

·Delirium is a sudden break in attention that flips on and off — and you can fix it. Dementia is a slow, steady loss of thinking that doesn't come back. Psychosis is seeing or believing things that aren't real.

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Normal physiology

·Your brain uses a careful balance of chemical messengers (neurotransmitters) to keep attention sharp, memory working, emotions steady, and your sense of what's real accurate. The prefrontal cortex (the front part of your brain, right behind your forehead) acts like a control tower — it filters distractions, holds focus, and checks if what you're seeing or thinking makes sense.

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What goes wrong

·In delirium, something sudden — infection, new medicine, dehydration, low oxygen, pain, constipation, or alcohol withdrawal — throws the brain's neurotransmitter balance way off. Acetylcholine (the attention messenger) drops and dopamine (the motivation and reality messenger) spikes, so the prefrontal cortex (your brain's control tower) goes offline and attention breaks. In dementia, brain cells die slowly — from Alzheimer's plaques (clumps of beta-amyloid protein), vascular damage (tiny strokes from high blood pressure or diabetes), Lewy bodies (clumps of alpha-synuclein protein), or frontotemporal shrinkage (neurons in the front and side of the brain dying off). Memory and thinking fade permanently, but attention stays okay early on. In psychosis, dopamine floods the mesolimbic pathway (the emotional and reward circuits deep in your brain) and the prefrontal cortex can't check if thoughts and perceptions match reality, so the person sees, hears, or believes things that aren't real — but attention and memory can still work fine at first.

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Hallmark signs

·Delirium: confusion that starts suddenly (over hours or a few days)
·Delirium: attention jumps around; the person cannot focus or follow a conversation
·Dementia: memory and thinking decline slowly (over months to years)
·Dementia: the person stays alert and aware of their surroundings (until very late stages)
·Psychosis: seeing, hearing, or believing things that are not real (hallucinations or delusions)
·Psychosis: thoughts may be disorganized or speech may jump from topic to topic without a clear link
·Delirium: the level of alertness swings — sometimes drowsy, sometimes agitated — within the same day
·Dementia: personality or behavior changes (apathy, irritability, losing social manners) develop over time

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Red flags · escalate now

·Sudden confusion with fever, low oxygen (blue lips or fingertips), very high or very low blood sugar, or a new medicine — suggests delirium and needs urgent work-up (blood tests, urine culture, chest X-ray, medication review) to find and fix the cause before the brain is permanently harmed
·Hallucinations or delusions with commands to hurt self or others, or the person cannot care for themselves safely (not eating, wandering into traffic, responding to voices) — needs immediate psychiatric evaluation and may need inpatient admission to keep the person and others safe
·Rapid memory loss over weeks (not years) with headache, seizures, fever, or new weakness on one side — may signal a brain bleed, tumor, herpes encephalitis, autoimmune encephalitis (like anti-NMDA receptor), or prion disease (Creutzfeldt-Jakob) rather than typical dementia, and requires urgent brain imaging (MRI) and lumbar puncture
·Delirium that does not improve after 72 hours of treating the cause (antibiotics for infection, stopping the offending drug, correcting electrolytes) — consider a second hidden cause, medication toxicity, or an unrecognized structural brain problem

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Workup

·Complete blood count (CBC) with differential
·Basic metabolic panel (BMP): sodium, potassium, glucose, creatinine, blood urea nitrogen (BUN)
·Urinalysis (UA) and urine culture
·Chest X-ray
·Medication review and urine drug screen
·Thyroid-stimulating hormone (TSH) and vitamin B12 level
·Head CT without contrast (or MRI if CT is unclear)
·Electroencephalogram (EEG) if nonconvulsive status epilepticus (a seizure that will not stop) suspected (delirium that does not improve with usual treatment or rhythmic twitching of face or hands)

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Treatment

·Identify and treat the medical cause: infection (antibiotics), medication side effect (stop the drug), low oxygen (oxygen or treat pneumonia or heart failure), low or high blood sugar (insulin or glucose), organ failure (dialysis for kidney failure, lactulose or rifaximin for liver failure)
·Reorient the person repeatedly: use their name, tell them the date and place, correct false beliefs gently, keep family or familiar people nearby, and use familiar objects like photos or glasses
·Avoid physical restraints; use one-to-one monitoring (a person stays with them at all times), soft lighting, a quiet room, a normal sleep schedule (wake them during the day, darken the room at night), and get them out of bed and walking as soon as safe
·Stop or reduce anticholinergic drugs (diphenhydramine, oxybutynin, promethazine, scopolamine), benzodiazepines (unless alcohol or benzodiazepine withdrawal), and opioids if possible
·Give haloperidol 0.5–1 mg IV/IM/PO or olanzapine 2.5–5 mg PO for severe agitation, hallucinations, or safety risk only—not for routine delirium
·For dementia after delirium clears: start donepezil 5 mg daily (increase to 10 mg after 4–6 weeks) or memantine 5 mg daily (titrate to 10 mg twice daily over 4 weeks). Consider adding memantine to donepezil for moderate to severe Alzheimer disease.
·For psychosis after delirium clears: start risperidone 0.5–1 mg daily or olanzapine 5–10 mg daily, plus cognitive-behavioral therapy (CBT) and case management to help with housing, medicine access, and regular appointments

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NCLEX trap

·Always find and treat the medical cause of delirium first. Antipsychotics are for safety only—if the patient might hurt themselves or others—not for cure. A delirious patient on antipsychotics without treatment of sepsis (a life-threatening infection spreading through the blood), low blood sugar, or stroke will die. The cause is what kills them, not the confusion itself.
·Delirium is sudden (hours to days) and reversible—you can fix it by treating the cause. Dementia is slow (months to years) and permanent—the brain cells die and cannot grow back. The speed of onset tells them apart. A patient with delirium can get completely better; one with dementia cannot.
·Delirium causes hallucinations too—especially at night, called sundowning (worsening confusion when the sun goes down). Look for sudden onset, broken attention (cannot focus or remember), and abnormal vitals (fever, fast heart, low oxygen). Treat the medical cause. Hallucinations from delirium go away when delirium is cured; you do not need months of antipsychotics.
·Restraints make delirium worse and can cause injury, blood clots, skin breakdown, or death. Instead, reorient the patient (tell them where they are, who you are, what day it is), keep them in a safe place with good lighting, fix the medical problem causing delirium, and use antipsychotics sparingly—only if they might hurt themselves or others.
·Delirium is a medical emergency. The person could have sepsis (infection spreading through the blood), stroke (blood clot blocking brain blood), heart attack, kidney failure, or poison in their system. Check blood work (complete blood count, sodium and potassium, kidney and liver tests, blood sugar), urine test, chest X-ray, and heart monitor immediately. Delirium can kill within hours if the cause is not treated.
·Delirious patients—especially older adults—are extra sensitive to medicines. Use the lowest dose needed for safety. Older delirious patients can have dangerous side effects (falls, stroke, heart rhythm problems, death) from normal doses. Once the medical cause is treated, you stop the antipsychotic. They do not need it long-term.

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