01Approach to the Critical Patient/attcp92

Immediate stabilization and reversible causes screen

›Immediate bedside checks

›Point-of-care glucose

›If glucose under 4 mmol/L, immediate dextrose

›Recheck glucose 15 minutes after correction

›Thiamine before or with dextrose when malnutrition, alcohol use, or bariatric surgery history suspected

›Wernicke encephalopathy overlap risk

›Pulse oximetry and ventilation status

›If SpO2 below target, supplemental oxygen and airway repositioning

›Hypoxia as immediately reversible precipitant

›If hypoventilation after sedatives or opioids, airway repositioning and assisted ventilation

›Naloxone trial when opioid toxicity suspected

›Vital sign screen

›Fever or hypothermia

›Sepsis bundle activation if fever with hemodynamic instability

›Hypotension or shock

›Balanced crystalloid bolus with reassessment

›Severe hypertension with end-organ signs

›Hypertensive emergency pathway

›Airway and safety priorities

›If GCS 8 or loss of airway reflexes, intubation

›Aspiration precautions with head of bed elevation

›If severe agitation endangering self or staff, minimal effective sedation

›Lowest effective dose before escalation

›Avoid deep sedation as a default target

Time-critical threats and rapid bedside checks

›Danger-weighted differential at the bedside

›Hypoxia and hypoglycemia

›Most common immediately reversible and lethal-if-missed causes

›Sepsis and CNS infection

›Fever, hypotension, or meningismus prompt early empiric workup

›Intracranial hemorrhage or ischemic stroke

›Focal deficit or anticoagulant exposure mandates emergent neuroimaging

›Nonconvulsive status epilepticus

›Persistent unexplained altered mental status without focal deficit

›Subtle motor automatisms or eye deviation

›Alcohol or benzodiazepine withdrawal delirium

›Autonomic hyperactivity with tremor

›See Alcohol withdrawal and Delirium Tremens topics for CIWA-Ar based benzodiazepine titration

›Isolation and exposure screen

›Suspected meningococcemia, viral encephalitis, or active respiratory pathogen

›Droplet or contact isolation pending diagnosis

›Do not delay resuscitation for isolation logistics

Medical, withdrawal, and primary psychiatric sorting

›Initial decision points

›High suspicion delirium due to medical illness

›Acute onset and fluctuating course

›Inattention as the core deficit

›High suspicion withdrawal syndrome

›Autonomic hyperactivity with tremor and diaphoresis

›Timeline consistent with cessation of alcohol or sedative-hypnotic use

›High suspicion primary psychiatric disease

›Known stable psychiatric history with normal attention and normal vitals

›Organized delusions without fluctuating course argue against delirium

›Delirium superimposed on dementia

›Acute change from a documented cognitive baseline

›See Dementia and behavioral crisis topic for chronic baseline management

Iatrogenic harms in the delirious patient

›Routine ED interventions that require modification here

›Intubation

›Post-intubation sedation choice affects delirium incidence

›Benzodiazepine infusions increase delirium risk versus dexmedetomidine or propofol

›Intubation and immobilization are themselves independent delirium precipitants

›Sedation

›Benzodiazepines are an independent risk factor for incident and worsening delirium

›Avoid outside alcohol or benzodiazepine withdrawal, seizure activity, or specific antipsychotic contraindication

›Target light sedation rather than deep sedation as a default

›Fluid loading

›Under-resuscitation from dehydration is a common precipitant

›Over-resuscitation with hypotonic fluid risks hyponatremia and worsens confusion

›Avoid hypotonic maintenance fluids in the acutely delirious patient

›Oxygen

›Hypoxia is a clear precipitant requiring correction

›Hyperoxia confers no benefit once saturation targets are met

›Excess oxygen in chronic hypercapnic patients risks worsening hypercapnia

›Vasopressors

›Needed when hypoperfusion is driving cerebral dysfunction

›Catecholamine exposure and IV line complications in an agitated patient are additional risks

›Secure access and consider central access early if prolonged support anticipated

›Mechanical circulatory support including intra-aortic balloon pump

›Not indicated for delirium itself

›If placed for an unrelated cardiogenic indication, immobilization from the device is itself a delirium risk factor

›Early mobilization planning with the device team

›Anticoagulation

›Not indicated for delirium

›If present for an unrelated indication, an agitated fall raises intracranial hemorrhage risk

›Lower threshold for head CT after any fall or head strike

›Fibrinolysis

›Not indicated for delirium generally

›If delirium reflects acute ischemic stroke, standard inclusion and exclusion criteria apply

›Agitation can impair ability to remain still for imaging and consent discussion

›Analgesia

›Undertreated pain is a common precipitant of agitation and delirium

›Opioids can independently cause or worsen delirium

›Avoid meperidine due to anticholinergic and neurotoxic metabolite risk

›Use lowest effective multimodal dose, adjusted for renal function

02History/hx69

Presentation pattern and subtype recognition

›Subtype identification

›Hyperactive delirium

›Agitation, hypervigilance, and hallucinations

›Hypoactive delirium

›Withdrawn affect, reduced psychomotor activity, and quiet confusion

›Most common subtype in older adults

›Most frequently missed subtype without directed screening

›Mixed delirium

›Fluctuation between hyperactive and hypoactive states within the same day

›Course description

›Acute onset over hours to days

›Distinguishes delirium from the gradual decline of dementia

›Fluctuating course through the day

›Sundowning pattern with worsening in the evening

›Sleep-wake cycle disruption

›Day-night reversal

Precipitant screen

›Drug-related precipitants

›New medication starts or dose changes

›Anticholinergics

›Opioids

›Benzodiazepines and sedative-hypnotics

›Corticosteroids

›Polypharmacy burden

›Cumulative anticholinergic load

›Withdrawal exposure

›Alcohol use pattern and last drink

03Physical Exam/exam63

General appearance and vital sign clues

›Physiologic screen

›Vital sign abnormalities

›Fever or hypothermia

›Hypoxia or tachypnea

›Hypotension or severe hypertension

›Hydration status

›Dry mucous membranes

›Skin turgor

›Level of consciousness pattern

›Somnolence alternating with agitation

›Suggests mixed delirium

Neurologic and mental status exam

›Mental status domains

›Attention

›Digit span or months-of-year-backward as bedside attention test

›Inattention is the core diagnostic deficit in delirium

›Orientation

›Time, place, person

›Thought content and perception

›Hallucinations

›Disorganized speech

›Psychomotor activity

›Hyperactive agitation

›Hypoactive withdrawal and reduced spontaneous movement

›Focal and structural screen

›Pupillary size and reactivity

›Asymmetry suggests intracranial pathology

04Differential Diagnosis/ddx44

Life threats to exclude

›Danger-weighted causes, common and reversible first

›Hypoxia and hypoglycemia

›Immediately correctable and rapidly lethal if missed

›Sepsis and systemic infection

›Occult source in older adults

›Alcohol or benzodiazepine withdrawal delirium

›See Alcohol withdrawal and Delirium Tremens topics

›Intracranial hemorrhage or ischemic stroke

›Focal deficit or anticoagulant exposure

›Nonconvulsive status epilepticus

›Unexplained persistent altered mental status

›CNS infection

›Meningitis or encephalitis

›Hepatic or uremic encephalopathy

›See Hepatic encephalopathy topic for precipitant-specific management

Delirium subtypes, mimics, and superimposed dementia

›Distinguishing delirium from dementia

›Onset

›Delirium acute, dementia gradual

›Course

›Delirium fluctuates, dementia is comparatively stable day to day

›Attention

›Impaired in delirium, relatively preserved in early dementia

›Delirium superimposed on dementia

›Acute change from documented baseline

›See Dementia and behavioral crisis topic for chronic behavioral management

›Psychiatric mimics

05Laboratory Tests/lt65

Core evaluation

›Initial labs

›Glucose

›Hypoglycemia under 4 mmol/L as a reversible contributor

›Electrolytes

›Sodium mmol/L

›Hyponatremia under 135 mmol/L as a precipitant

›Potassium mmol/L

›Hypokalemia potentiates QT prolongation with antipsychotic use

›Calcium mmol/L

›Hypercalcemia as a precipitant

›Magnesium mmol/L

›Hypomagnesemia potentiates QT prolongation

›Renal function

›Creatinine umol/L

›Uremic encephalopathy and opioid metabolite accumulation risk

›Liver tests

›Bilirubin and transaminases

›Hepatic encephalopathy concern, see Hepatic encephalopathy topic

›CBC

›Leukocytosis for infection

›Anemia as a hypoxia contributor

Infection workup

›Infection markers and cultures

›Blood cultures

›Fever or shock, two sets before antibiotics when feasible

›Do not delay antibiotics in an unstable patient

›Urinalysis and urine culture

06Diagnostic Tests/dt54

Scoring Systems

›Delirium screening and severity tools

›Confusion Assessment Method

›Feature 1, acute onset and fluctuating course

›Feature 2, inattention

›Feature 3, disorganized thinking

›Feature 4, altered level of consciousness

›Diagnostic algorithm requires features 1 and 2, plus either 3 or 4

›Confusion Assessment Method for the ICU

›Adapted for mechanically ventilated or nonverbal patients

›Assessed only when Richmond Agitation-Sedation Scale is -3 or higher

›If -4 or -5, reassess later rather than scoring

›4AT rapid screening tool

›Alertness component

›Abbreviated mental test four component

›Attention component, months of the year backward

›Acute change or fluctuating course component

›Score 4 or higher, delirium likely

›Score 1 to 3, possible cognitive impairment, further assessment needed

›Score 0, delirium unlikely

›Richmond Agitation-Sedation Scale

›Used for sedation depth monitoring, see Agitation-behavioral emergency topic for full scale

›Target RASS 0 to -2 for most sedation goals

›Deeper sedation reserved for specific indications such as status epilepticus or elevated intracranial pressure

›Delirium Rating Scale severity tools

›Research and specialist severity tracking, not a primary ED screening tool

MRI

›Neuroimaging MRI role

07Disposition/dispo34

Level of care decisions

›Admission indications

›Delirium suspected or confirmed with unresolved precipitant

›Underlying medical trigger identified or still being investigated

›Unstable physiology

›Persistent abnormal vital signs

›Inability to ensure safe supervision at home

›No reliable caregiver

›ICU criteria

›Airway protection concern

›GCS 8 or loss of airway reflexes

›Refractory severe agitation requiring continuous infusion sedation

›Dexmedetomidine or equivalent infusion requirement

›Hemodynamic instability

›Vasopressor requirement

›Need for continuous EEG monitoring

›Suspected nonconvulsive status epilepticus

Transfer and specialty triggers

›Transfer criteria for non-tertiary EDs

›Neurosurgical need

›Subdural hematoma or mass lesion requiring intervention

›EEG unavailable locally

›Suspected nonconvulsive status epilepticus requiring continuous monitoring

›ICU-level sedation or monitoring unavailable locally

›Refractory agitation requiring titrated infusion sedation

›Toxicology or psychiatric specialty unavailable locally

›Complex co-ingestion or safety planning need

08Treatment/t126

Nonpharmacologic management, environment, and restraint

›Environmental and supportive measures

›Reorientation

›Clocks, calendars, and frequent staff reorientation

›Sensory aid restoration

›Return glasses and hearing aids as soon as safe

›Sleep-wake hygiene

›Minimize overnight interruptions and reduce daytime napping

›Early mobilization

›Out of bed as soon as medically safe

›Hydration and nutrition

›Oral intake support unless contraindicated

›Pain control

›Multimodal analgesia before assuming behavioral cause

›Family and familiar presence

›Reduces distress and supports reorientation

›Physical restraint principles

›Indications

›Immediate danger to self or staff after failed de-escalation

›Technique

›Least restrictive effective method, supine with head elevation when feasible

›Monitoring

›Continuous pulse oximetry and frequent reassessment for release

›Medical risks

›Prolonged four-point or prone restraint risks positional asphyxia and rhabdomyolysis

›Rhabdomyolysis can progress to hyperkalemia and cardiac arrest if unrecognized

›Restraints themselves are an independent delirium precipitant

›Remove as soon as safety allows

Pharmacologic strategy selection and principles

›Core principle

›Treat the precipitant first

›Pharmacologic sedation does not treat delirium, it manages distressing symptoms or danger

›Reserve medication for distressing psychotic symptoms or dangerous agitation

›Do not medicate quiet hypoactive delirium for sedation purposes

›Choose the lowest effective dose and reassess frequently

›Start doses lower than standard primary-psychiatric-agitation protocols, especially in older adults

›See Agitation-behavioral emergency topic for high-dose rapid tranquilization in uncontrolled violent agitation

›Antipsychotics generally preferred over benzodiazepines in non-withdrawal delirium

›Benzodiazepines independently worsen and can precipitate delirium outside withdrawal or seizure indications

Antipsychotic dosing and monitoring

›Haloperidol

›Haloperidol PO or IV 0.5 mg for distressing hyperactive symptoms

›Repeat every 4 to 6 hours as needed

›Maximum 3 mg in 24 hours in frail older adults

›In younger ICU patients without QTc risk, higher total daily dosing may be used under specialist guidance

›IV route carries greater QTc prolongation risk than PO or IM

›ECG before initiation and during use

›Do not use in Parkinson disease or Lewy body dementia

›High extrapyramidal and neuroleptic sensitivity risk

›Quetiapine

›Quetiapine PO 12.5 to 25 mg at night

›Titrate by 12.5 to 25 mg increments

›Maximum approximately 100 to 200 mg per day for delirium

›Preferred over haloperidol in Parkinson disease or Lewy body dementia

›Lower extrapyramidal risk

›Risperidone

›Risperidone PO 0.25 to 0.5 mg

›Repeat every 4 to 6 hours as needed to a similar low-dose ceiling as haloperidol

›Olanzapine

›Olanzapine PO 2.5 to 5 mg

›Higher anticholinergic burden than haloperidol or risperidone, less preferred in delirium

›Avoid concomitant parenteral benzodiazepine within a short interval

›Combined respiratory depression and hypotension risk

›Safety monitoring for all antipsychotics

›QTc greater than 500 ms

›Increased torsades de pointes risk, especially with concurrent hypokalemia or hypomagnesemia

›Correct potassium and magnesium before or alongside antipsychotic dosing

›Baseline QT-prolonging medication review

›Additive risk with other QT-prolonging drugs

Benzodiazepine and alternative sedative dosing

›Benzodiazepines, narrow indication in delirium

›Not recommended as first-line for non-withdrawal delirium

›Worsens hypoactive delirium and increases fall and respiratory depression risk in older adults

›Lorazepam PO or IV 0.5 to 1 mg

›Reserved for alcohol or benzodiazepine withdrawal, seizure-related agitation, or antipsychotic contraindication

›See Alcohol withdrawal and Delirium Tremens topics for symptom-triggered dosing protocols

›A clinician electing a trial dose still needs the exact number even when the drug is discouraged

›Low anticholinergic-burden alternatives

›Trazodone PO 25 to 50 mg at night

›For sleep-wake disruption without significant agitation

›Melatonin PO 3 to 5 mg at night

›Circadian support, low harm, weak evidence for delirium prevention

Dexmedetomidine and ICU delirium infusion

›Infusion protocol

›Dexmedetomidine IV infusion 0.2 to 0.7 mcg/kg/hour

›Omit loading bolus in delirium-prone patients

›Bolus dosing is associated with bradycardia and hypotension

›Titrate by 0.1 to 0.2 mcg/kg/hour every 30 minutes to target RASS 0 to -2

›Maximum 1.5 mcg/kg/hour

›Monitoring cadence

›Continuous ECG and blood pressure monitoring

›Vital signs and RASS reassessment every 15 minutes during titration

›Extend to hourly once the target is stable

›Weaning

›Taper by approximately half or over several hours rather than abrupt discontinuation

›Abrupt discontinuation risks rebound hypertension, tachycardia, and agitation

›Precautions

›Bradycardia and hypotension

›Reduce rate or hold for symptomatic bradycardia

Precipitant-directed therapy

›Infection

›Treat per suspected source and local antibiogram

›See Sepsis, Urosepsis, and Bacterial meningitis topics for regimens

›Withdrawal

›Alcohol or benzodiazepine withdrawal delirium

›See Alcohol withdrawal and Delirium Tremens topics for full symptom-triggered protocol

›Metabolic and nutritional

›Thiamine IV 100 mg daily for malnutrition, alcohol use, or bariatric surgery risk

›Given before or with glucose

›Higher-dose protocols per local practice when Wernicke encephalopathy is suspected

›Electrolyte correction

›Potassium and magnesium repletion to normal range

›Reduces QT-prolongation risk with antipsychotic use

›Sodium correction no faster than 8 mmol/L per 24 hours

›Retention and constipation

›Bladder decompression for urinary retention

›Bowel regimen for fecal impaction

›Medication reconciliation

›Discontinue anticholinergics, unnecessary sedatives, and recently started deliriogenic agents

›Reassess necessity of each active medication daily

›Hypoxia and hypercapnia correction

›Supplemental oxygen to target, see nonpharmacologic and monitoring sections for exceptions by comorbidity

Refractory agitation and troubleshooting

›Therapy-not-working reassessment

›Persistent agitation despite antipsychotic and benzodiazepine trial

›Reassess for undiagnosed pain

›Reassess for urinary retention or fecal impaction

›Reassess for evolving alcohol or benzodiazepine withdrawal

›Reassess for an evolving CNS catastrophe such as expanding hemorrhage or nonconvulsive status epilepticus

›Reconsider whether the primary driver was ever medication-responsive

›Escalation pathway

›ICU-level continuous infusion sedation when danger persists despite intermittent dosing

›See Agitation-behavioral emergency topic for dissociative sedation dosing in immediately dangerous uncontrolled violence

09Special Populations/sp47

Pregnancy

›Pregnancy considerations

›Obstetric-specific differential

›Eclampsia or severe preeclampsia with hypertension and headache

›Amniotic fluid embolism in the peripartum period

›Postpartum psychosis and postpartum infection as mimics

›Medication selection

›Haloperidol generally preferred when an antipsychotic is needed

›Benzodiazepines used only when benefit clearly outweighs risk

›Obstetric coordination

›Fetal monitoring when viable gestation and maternal stabilization achieved

›Early obstetrics consultation

Geriatric

›Older adult considerations

›Highest-risk population for delirium

›Hypoactive subtype predominates and is systematically underrecognized

›Formal attention testing on every altered or unusually quiet older patient

›Polypharmacy and anticholinergic burden

›Deprescribing review as part of the precipitant workup

›Medication dosing

›Start at the lowest listed antipsychotic dose and titrate slowly

›Avoid benzodiazepines outside withdrawal indications

›Paradoxical worsening of confusion and falls risk

›Delirium superimposed on dementia

›Acute change from a documented cognitive baseline

›See Dementia and behavioral crisis topic for chronic behavioral management

›Falls and sensory aid restoration

›Return glasses and hearing aids promptly

10Background/b33

Epidemiology

›Prevalence

›Roughly 8 to 17 percent of older adults presenting to the ED

›Roughly 18 to 35 percent of hospitalized older adults at some point during admission

›Up to 60 to 80 percent of mechanically ventilated ICU patients

›Roughly 10 to 50 percent of postoperative patients depending on surgery type

›Higher after hip fracture repair and cardiac surgery

›Detection gap

›Missed by ED clinicians in the majority of encounters, historically cited around two-thirds to three-quarters

›Hypoactive subtype disproportionately missed

›Outcomes

›Associated with roughly a twofold increase in in-hospital mortality

›Associated with longer hospital stay and higher rates of institutionalization at discharge

›Associated with increased long-term risk of incident dementia after an episode

Pathophysiology

›Proposed mechanisms

›Neuroinflammation

›Cytokine-mediated blood-brain barrier disruption, prominent in sepsis and after surgery

›Cholinergic deficiency hypothesis

›Anticholinergic medications precipitate or worsen delirium

›Relative dopaminergic excess

›Rationale underlying dopamine-blocking antipsychotic use for distressing hyperactive symptoms

›Network disconnection and EEG slowing

›Diffuse cortical dysfunction pattern

›Circadian and melatonin disruption

›Contributes to sleep-wake cycle reversal

Therapeutic Considerations

›Treatment rationale

11Patient Discharge Instructions/pdi22

copy discharge instructions

›Discharge instructions

›Condition summary

›Confusion episode and the cause identified in the ED

›Medication guidance

›Take prescribed medications only as directed

›Avoid alcohol and non-prescribed sedating medications

›Warning symptoms to act on

›New or worsening confusion

›Unable to stay awake or difficult to rouse

›Fever above 38 degrees Celsius

›Falls or new weakness

›Return to ED immediately for

›Worsening confusion or unresponsiveness

›Fever with shaking chills

›New weakness, numbness, or difficulty speaking

›Seizure activity

›Safety planning

›Reliable adult supervision for 24 to 48 hours

›Do not drive until cleared

›Follow-up

›Primary care or geriatric follow-up within 3 to 7 days

›Sooner if symptoms recur

12References/r19

Clinical guidelines and key sources

›Reference list

›Society of Critical Care Medicine PADIS guidelines for pain, agitation and sedation, delirium, immobility, and sleep disruption in adult ICU patients

›Recommends against routine antipsychotic prophylaxis for delirium prevention

›Favors nonpharmacologic multicomponent prevention bundles

›American Geriatrics Society consensus recommendations on postoperative delirium in older adults

›Nonpharmacologic prevention emphasis

›Conservative low-dose antipsychotic use for distressing symptoms

›NICE clinical guideline on delirium prevention, diagnosis, and management

›Multicomponent nonpharmacologic intervention as first-line

›MIND-USA randomized trial of haloperidol and ziprasidone in critically ill patients with delirium

›No benefit on delirium duration or survival

›Inouye and colleagues, Confusion Assessment Method validation and Hospital Elder Life Program literature

›Foundation for bedside delirium screening and multicomponent prevention

›Han and colleagues, studies on missed delirium detection in the emergency department

›Documents high rates of missed hypoactive delirium

›Alcohol withdrawal and Delirium Tremens topics

›CIWA-Ar based benzodiazepine titration protocols

›Dementia and behavioral crisis topic

›Chronic baseline behavioral management

Evidence & Review

Evidence & Review