Psychosocial, Behavioral & Cognitive · Topic 1 of 7

Delirium

Psychosocial · acute brain dysfunction

Delirium

Acute, fluctuating inattention from a medical cause. Screen every shift with the CAM-ICU, find and reverse the cause, and do not reach for routine antipsychotics.

Key numbers

CAM-ICU: acute change, inattention, plus one1 + 2 + (3 or 4)

Screen every shift with CAM-ICURASS −3 or lighter

Delirium raises 1-year mortality30–50% die within 1 yr

01 · What it isAcute, fluctuating inattention from illness

Delirium = a disturbance in attention and awareness that develops over hours to days, fluctuates through the day and alters cognition, caused by a medical condition, a substance or medication, or withdrawal.

02 · WatchScreen every shift with CAM-ICU

Screen ICU adults for delirium every shift with CAM-ICU or ICDSC; the patient must respond to voice (RASS −3 or lighter) — at RASS −4 or −5, record unable to assess and recheck.

03 · The ruleNo routine antipsychotics for delirium

Do not routinely treat delirium with haloperidol or an atypical antipsychotic: in MIND-USA neither shortened delirium, ventilation, stay or mortality; PADIS 2018 suggests against routine use and the 2025 update makes no recommendation.

Presentation

What you'll see

Hypoactive delirium looks like depressionHypoactive delirium — quiet, withdrawn, lethargic — is common in very old patients, is easily mistaken for depression and is missed without routine screening; antipsychotics and benzodiazepines are not used to treat it.

Diagnosis & monitoring

Work-up

CAM-ICU: acute change, inattention, plus one must knowCAM-ICU is positive with (1) acute change or fluctuating mental status plus (2) inattention, plus either (3) altered level of consciousness (any RASS other than 0) or (4) disorganized thinking.

Do right now

In this order

First moves

Screen every shift with CAM-ICURASS −3 or lighter

→

Search for and reverse the cause

→

Stop anticholinergics and sedatives in older adults

→

Prevent with multicomponent nonpharmacologic care

→

Low-dose antipsychotic only for dangerous agitation

Why each step

Screen every shift with CAM-ICUScreen ICU adults for delirium every shift with CAM-ICU or ICDSC; the patient must respond to voice (RASS −3 or lighter) — at RASS −4 or −5, record unable to assess and recheck.

Search for and reverse the causeTreat delirium by finding and correcting its cause: review every medication (anticholinergics, benzodiazepines, opioids, sedatives, steroids), and look for infection, hypoxia, hypoglycemia, electrolyte and fluid disorders, withdrawal, urinary retention and constipation.

Stop anticholinergics and sedatives in older adultsIn older adults with or at high risk of delirium, avoid drugs that induce or worsen it (AGS Beers 2023): anticholinergics (e.g., diphenhydramine), benzodiazepines, Z-drug hypnotics, H2 blockers and antipsychotics; minimize corticosteroids and opioids.

Prevent with multicomponent nonpharmacologic carePrevention is nonpharmacologic and multicomponent: frequent reorientation, glasses and hearing aids, sleep protocol, early mobility, hydration and nutrition, scheduled pain control, and early removal of catheters and restraints.

Low-dose antipsychotic only for dangerous agitationReserve a short course of low-dose haloperidol or an atypical antipsychotic for severe agitation or distressing psychosis that threatens safety after nonpharmacologic measures fail; stop it as soon as the agitation resolves.

Management

Orders

Dexmedetomidine when agitation blocks extubationFor a mechanically ventilated adult whose agitated delirium is preventing weaning or extubation, PADIS suggests dexmedetomidine (conditional recommendation).

Avoid physical restraints; use a sitterPhysical restraints, IV lines and bladder catheters worsen agitation and injury; a sitter (constant observer) can often replace restraints, and any restraint must be released regularly and stopped as soon as possible.

Targeted work-up for the causeUsual work-up: CBC, electrolytes, renal function, glucose, oximetry or ABG, urinalysis, chest radiograph and cultures if infection is possible, drug levels, urine drug screen, head CT or MRI; EEG for suspected nonconvulsive status.

Red flags & don'ts

Avoid harm

Avoid benzodiazepines unless alcohol or benzodiazepine withdrawal avoidAvoid benzodiazepines in delirium — they worsen confusion and sedation; the exception is delirium from alcohol or benzodiazepine withdrawal, where IV benzodiazepines are the drugs of choice.

Delirium raises 1-year mortality complication30–50% of hospitalized patients with delirium die within 1 year; delirium also raises the risk of lasting cognitive and functional decline and institutionalization for up to 2 years.

The rules

Know these

No drug prophylaxis for deliriumDo not give haloperidol, an atypical antipsychotic, dexmedetomidine, a statin or ketamine to prevent delirium in all critically ill adults (PADIS conditional recommendation).

Delirium or a primary psychiatric disorder?

Commonly confused

Onset	Hours to days
Attention	Impaired — the core feature
Level of consciousness	Fluctuates over the day
Cause	Medical illness, drug or withdrawal
Quiet, withdrawn older patient	Think hypoactive delirium first

More detail

Reference

Show 4 reference facts

Delirium affects about 15–50% of older adults at some point during a hospital stay; dementia, Parkinson disease, stroke, polypharmacy, sensory deprivation and ICU care raise the risk.

Proposed mechanisms include cholinergic deficiency, impaired cerebral oxidative metabolism and inflammatory cytokines (IL-1β, IL-6, TNF-α) — which is why anticholinergic drugs so readily precipitate delirium in older adults.

The 2025 PADIS focused update conditionally suggests melatonin over no melatonin for ICU adults, and dexmedetomidine over propofol for ventilated adults when light sedation or less delirium is the priority.

Ophthalmoplegia and ataxia with confusion suggest Wernicke encephalopathy; correct thiamine and vitamin B12 deficiency and provide adequate nutrition and hydration.

Pearl

Delirium is a symptom, not a diagnosis: the antipsychotic quiets it, the work-up cures it.

Sources · Merck Manual Professional — Delirium · Devlin JW et al. Clinical Practice Guidelines for the Prevention and Management of Pain, Agitation/Sedation, Delirium, Immobility, and Sleep Disruption in Adult Patients in the ICU (PADIS). Crit Care Med 2018;46:e825–e873 · Lewis K et al. A Focused Update to the PADIS Clinical Practice Guidelines (anxiety, agitation/sedation, delirium, immobility, sleep). Crit Care Med 2025 · ICU Delirium and Cognitive Impairment Study Group (Vanderbilt CIBS) — Management of Delirium in the ICU · Chanques G et al. The 2014 updated version of the CAM-ICU compared to DSM-5 and other methods used by intensivists. Ann Intensive Care 2018;8 (Table 1: CAM-ICU features) · ICU Delirium and Cognitive Impairment Study Group — Monitoring Delirium in the ICU (assess once per shift with CAM-ICU or ICDSC per PADIS 2018) · American Geriatrics Society 2023 Updated AGS Beers Criteria (Table 3: delirium and dementia). J Am Geriatr Soc 2023;71:2052–2081 · American Geriatrics Society abstracted clinical practice guideline for postoperative delirium in older adults. J Am Geriatr Soc 2015;63:142–150 (reaffirmed 2021) · Girard TD et al. Haloperidol and Ziprasidone for Treatment of Delirium in Critical Illness (MIND-USA). N Engl J Med 2018;379:2506–2516 · SCCM / Vanderbilt — Confusion Assessment Method for the ICU (CAM-ICU) Flowsheet (features 1–4; RASS other than zero = altered level of consciousness) · Ely EW et al. The Complete CAM-ICU Training Manual (2016): RASS ≥ −3 proceed to CAM-ICU; RASS −4/−5 stop, unable to assess, recheck later · Guideline Central — SCCM PADIS guideline summary: 2025 focused update and 2018 recommendations (delirium prevention, treatment, dexmedetomidine) · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).