Perioperative & Surgical Care

Postoperative delirium: prevention and management

Clinical Overview and When to Suspect Postoperative Delirium

— Incidence 15–25% after major elective surgery, 40–60% after hip fracture repair, up to 80% in postoperative ICU patients

— Independently associated with 2-fold increase in 1-year mortality, prolonged LOS, new nursing-home placement, and persistent cognitive decline

— Any acute change in mental status, attention, or behavior in a postoperative patient

— "Sweet, cooperative grandma is now pulling at her IV" — hypoactive delirium is more common and more often missed than hyperactive

— New disorientation, paranoid statements, hallucinations, reversal of sleep-wake cycle, or simply "not herself" per family

— Age ≥65, baseline cognitive impairment/dementia, frailty, sensory impairment (vision/hearing), prior delirium, polypharmacy, depression, alcohol use, poor functional status, malnutrition

— Anesthesia depth, benzodiazepines, anticholinergics, meperidine, undertreated pain, hypoxia, hypotension, infection, urinary retention, constipation, electrolyte derangements, sleep disruption, restraints, indwelling catheters, blood loss/anemia

Board pearl: On Step 3, an elderly hip-fracture patient who becomes inattentive on POD 2 has delirium until proven otherwise — do not anchor on "dementia worsening" or "ICU psychosis." The cognitive baseline was preoperative; any acute deviation triggers a delirium workup.

Step 3 management framing: Think of postoperative delirium in three CCS moves — (1) screen and recognize, (2) hunt for and reverse precipitants, (3) use nonpharmacologic prevention/treatment first and reserve antipsychotics for danger to self/others. Early recognition on rounds, not at 3 AM by the covering intern, is the single biggest outcome lever.

Definition: Acute, fluctuating disturbance of attention and awareness with altered cognition, developing within hours to days after surgery — a medical emergency, not "just sundowning."

Epidemiology:

When to suspect (peak onset POD 1–3):

Key predisposing risk factors (the patient brings these to the OR):

Key precipitating factors (the perioperative course adds these):

Presentation Patterns and Key History

— Hyperactive (~25%): agitation, restlessness, pulling lines, combative, hallucinations — easy to identify, often over-treated with antipsychotics

— Hypoactive (~50%): lethargy, withdrawal, flat affect, slowed responses — most common and most missed; mistaken for depression, fatigue, or "doing well and quiet"

— Mixed (~25%): fluctuates between the two within the same day

— Acute onset and fluctuating course (hours to days, waxing/waning)

— Inattention (cannot recite months backward, digit span, days of week reverse)

— Plus either disorganized thinking (rambling, illogical) or altered level of consciousness (hyperalert or drowsy)

— Baseline cognition: "Was she paying bills, driving, managing meds before surgery?"

— Sensory aids at home: glasses, hearing aids (often left at home or lost in OR)

— Substance history: daily alcohol (withdrawal peaks POD 2–4), benzodiazepines, opioids, cannabis

— Medication reconciliation: anticholinergics (diphenhydramine, oxybutynin, TCAs), benzos, sleep aids, gabapentinoids

— Prior delirium episodes, especially postoperative

— POD 0–1: residual anesthesia, hypoxia, hypotension, hypoglycemia

— POD 2–4: alcohol/benzo withdrawal, pneumonia, UTI, urinary retention, opioid accumulation

— POD 3–7: surgical site infection, DVT/PE, MI, anastomotic leak

— POD 5+: delayed sepsis, C. difficile, electrolyte shifts, deconditioning delirium

Key distinction: Delirium vs dementia vs depression — delirium has acute onset, fluctuation, and inattention; dementia is chronic and gradual with preserved attention early; depression has stable affect with intact (if slow) attention. A patient with dementia who acutely worsens has delirium superimposed on dementia — treat as delirium.

Board pearl: A "quiet, sleepy" elderly postop patient who fails to engage on rounds is the classic hypoactive delirium vignette — order a CAM, not just "encourage ambulation."

Three motoric subtypes — recognize all three:

Core diagnostic features (DSM-5 / CAM):

History — ask the family, not just the chart:

Temporal clues by postoperative day:

Physical Exam Findings and Bedside Assessment

— CAM (Confusion Assessment Method): requires (1) acute onset + fluctuation AND (2) inattention, PLUS (3) disorganized thinking OR (4) altered LOC. Sensitivity ~90% when used correctly

— CAM-ICU for intubated/nonverbal patients; 4AT is a rapid alternative (alertness, AMT-4, attention, acute change)

— Attention tests: months of year backward, days of week backward, serial 7s, digit span (normal ≥5 forward)

— RASS (Richmond Agitation-Sedation Scale): any score other than 0 in a non-sedated patient is abnormal

— Vitals: fever (infection), tachycardia (withdrawal, PE, sepsis, pain), hypotension (sepsis, hypovolemia), hypoxia (pneumonia, PE, atelectasis), hypertension + tachycardia + tremor (alcohol withdrawal)

— Hydration: dry mucous membranes, poor skin turgor, orthostasis

— Bladder scan: palpable suprapubic fullness — urinary retention is a top reversible cause

— Abdomen: distension, absent bowel sounds (ileus), tenderness (anastomotic leak, ischemia), fecal impaction on rectal exam

— Pupils (pinpoint = opioid; dilated = anticholinergic, withdrawal)

— Asterixis (uremia, hepatic, hypercapnia), myoclonus (serotonin syndrome, uremia)

— Focal deficits mandate stroke workup — delirium alone should not produce lateralizing signs

— Tremor + diaphoresis + autonomic hyperactivity → alcohol/benzo withdrawal

— Wound: erythema, drainage, dehiscence

— Indwelling Foley, CVC, drains — all delirium amplifiers and infection sources; remove what isn't needed today

CCS pearl: On the CCS case, early orders should include "bladder scan," "remove Foley if not needed," "medication reconciliation," and "CAM assessment q-shift" — these score points and reflect real-world prevention bundles.

Board pearl: Focal neurologic signs in a "delirious" postop patient = stop and get a non-contrast head CT before blaming opioids.

Mental status exam — structured bedside tools:

General exam — look for the precipitant:

Focused neuro exam:

Surgical site and lines:

Diagnostic Workup — Initial Labs, Imaging, and Bedside Tests

— CBC with differential (leukocytosis → infection; anemia → hypoperfusion)

— BMP (Na, K, BUN/Cr, glucose) — hyponatremia, hypernatremia, AKI, hypo/hyperglycemia are classic reversible causes

— Calcium, magnesium, phosphate (hypercalcemia → confusion; hypomagnesemia → arrhythmia and seizure threshold)

— LFTs and ammonia if cirrhosis or unexplained encephalopathy

— TSH if subacute and no clear cause

— Lactate if sepsis or hypoperfusion suspected

— ABG/VBG for hypoxia, hypercapnia (especially COPD, OSA, opioid excess), acid-base

— Glucose fingerstick immediately — hypoglycemia is rapidly reversible and deadly

— UA + urine culture (UTI is the #1 reversible cause in elderly postop patients)

— Blood cultures × 2 if febrile or hemodynamic concern

— CXR for pneumonia, atelectasis, effusion, pulmonary edema

— Wound inspection and cultures if purulent

— C. difficile PCR if diarrhea + recent antibiotics

— Rule out silent MI (especially diabetics, elderly), new arrhythmia (AF with RVR), QTc baseline before any antipsychotic

— Head CT (non-contrast) if focal deficits, fall with head strike, anticoagulated, papilledema, seizure, or no other cause identified after workup — not routine

— CTA chest if hypoxia + tachycardia + risk factors for PE

— Reconcile all meds given in OR and on the floor — flag benzodiazepines, anticholinergics, meperidine, high-dose opioids, gabapentinoids, H2 blockers, steroids, fluoroquinolones

Step 3 management: Order the DELIRIUM workup bundle — fingerstick glucose, BMP/Mg/Phos, CBC, UA, CXR, ECG, ABG, and a bladder scan — before adding any new sedating drug. The exam loves the answer "review medication list and treat reversible causes" over "give haloperidol."

Board pearl: A postop UTI in a 78-year-old who "got confused" — treat the UTI; the delirium follows.

Delirium is clinical — labs and imaging hunt for the precipitant, not the diagnosis itself.

First-tier labs (every new postoperative delirium):

Infection screen — postop "delirium fever" workup:

ECG:

Imaging triggers:

Medication review (do this before ordering more tests):

Diagnostic Workup — Advanced or Confirmatory Studies

— MRI brain if persistent delirium >72 h despite reversal of identifiable causes, new focal signs, suspicion of posterior circulation stroke (CT misses), or watershed infarct after intraoperative hypotension

— Consider in cardiac surgery patients (embolic shower) and carotid endarterectomy (hyperperfusion syndrome)

— Suspected non-convulsive status epilepticus (NCSE): fluctuating LOC with no clear cause, subtle eye/face twitching, prior seizures, recent stroke, brain surgery

— Differentiate delirium (diffuse slowing) from psychogenic causes

— Triphasic waves suggest metabolic encephalopathy (hepatic, uremic)

— Fever + meningismus, immunocompromise, recent neurosurgery/spinal anesthesia, suspicion of meningitis/encephalitis

— Always image first if focal signs or papilledema

— Urine drug screen if substance use suspected or unexplained delirium

— Digoxin, lithium, valproate, phenytoin levels in patients on these drugs

— Salicylate, acetaminophen if intentional ingestion possible

— Serum alcohol and CIWA scoring for withdrawal

— Cortisol (adrenal insufficiency, especially chronic steroid users with perioperative undertreatment)

— B12, folate, thiamine — empirically replete thiamine before glucose in malnourished or alcoholic patients to prevent Wernicke encephalopathy

— TSH, free T4

— Troponin if ECG changes or risk factors (silent MI is a classic POD 2–3 cause)

— BNP and echo if volume overload or new heart failure suspected

— D-dimer is unhelpful postop (always elevated); go straight to CTPE if clinical suspicion

Key distinction: Triphasic waves on EEG = metabolic encephalopathy, not seizure. Rhythmic spike-wave with subtle motor findings = NCSE — needs antiepileptic, not antipsychotic.

Board pearl: Persistent delirium >72 h with negative standard workup → think NCSE, occult stroke, or undertreated withdrawal. Get an EEG.

When initial workup is unrevealing, escalate selectively — not shotgun.

Neuroimaging — when to go beyond initial CT:

EEG — narrow but high-yield indications:

Lumbar puncture — rare but mandatory if:

Toxicology and drug levels:

Endocrine and nutritional second-tier:

Cardiopulmonary deeper dive:

Risk Stratification and Prevention-First Management Logic

— Age ≥70, baseline MoCA <26 or known cognitive impairment, frailty (gait speed <0.8 m/s, grip weakness), polypharmacy ≥5 drugs, sensory impairment, ASA ≥3, prior delirium, hip fracture or cardiac surgery

— Routine preoperative cognitive screening (Mini-Cog, MoCA) is recommended by the American Geriatrics Society for patients ≥65

— Reorientation: clock, calendar, whiteboard with date and team names, family at bedside

— Sensory optimization: glasses on, hearing aids in, dentures placed

— Mobility: out of bed POD 1, ambulation TID, PT/OT early

— Sleep hygiene: cluster nighttime care, dim lights, no vitals 11 PM–5 AM if stable, eye masks, earplugs, daytime light exposure

— Hydration and nutrition: early diet advancement, oral hydration, swallow evaluation if aspiration risk

— Constipation and urinary retention prevention: scheduled bowel regimen, early Foley removal (POD 1–2 unless required)

— Pain control without delirogenic drugs: scheduled acetaminophen, regional anesthesia, opioid-sparing multimodal

— Avoid/minimize: benzodiazepines, anticholinergics (diphenhydramine, hydroxyzine), meperidine, prolonged NPO, physical restraints

— Regional/neuraxial anesthesia preferred when feasible (hip fracture, knee replacement)

— Avoid deep general anesthesia; processed EEG (BIS) monitoring to target lighter depth reduces delirium in elderly

— Dexmedetomidine sedation (vs benzodiazepine-based) reduces ICU delirium

Step 3 management: When asked "best next step to prevent postoperative delirium in a 78-year-old undergoing hip repair," choose multicomponent nonpharmacologic intervention (HELP-style bundle) — not prophylactic haloperidol, melatonin, or cholinesterase inhibitors (no consistent benefit).

Board pearl: Routine prophylactic antipsychotics do not prevent delirium and may cause harm — do not pick them on the exam.

Preoperative risk stratification — the highest-yield intervention is identifying who is at risk before surgery.

High-risk preoperative profile:

Multicomponent nonpharmacologic prevention bundle (HELP — Hospital Elder Life Program; reduces incidence ~40%):

Anesthetic considerations:

Pharmacotherapy — First-Line Drug Regimen

— Reverse hypoxia, hypoglycemia, electrolyte disturbance, retention, pain, infection, withdrawal

— Discontinue or substitute offending drugs (stop diphenhydramine, switch meperidine → scheduled acetaminophen + low-dose oxycodone, taper benzodiazepines cautiously)

— Haloperidol 0.25–0.5 mg PO/IV/IM q4–6h PRN; max ~3 mg/24h in elderly. Onset 20–30 min IV

— Monitor QTc; hold if QTc >500 ms or baseline arrhythmia; check K and Mg

— Avoid in Parkinson disease and Lewy body dementia (severe EPS, neuroleptic sensitivity)

— Quetiapine 12.5–25 mg PO BID — preferred in Parkinson/Lewy body

— Risperidone 0.25–0.5 mg PO BID

— Olanzapine 2.5–5 mg PO/IM daily

— All carry FDA black-box warning for increased mortality in elderly dementia patients — use lowest effective dose, shortest duration, document indication

— Benzodiazepines — EXCEPT for alcohol/benzodiazepine withdrawal, seizures, or NMS/serotonin syndrome

— Diphenhydramine, hydroxyzine, scopolamine, atropine, oxybutynin

— Meperidine (normeperidine accumulates and causes delirium/seizures)

— Alcohol withdrawal delirium (DTs): symptom-triggered lorazepam or diazepam via CIWA protocol; thiamine 100 mg IV before glucose; treat hypomagnesemia

— ICU sedation: dexmedetomidine reduces delirium duration vs propofol or benzodiazepines

Step 3 management: "Start low, go slow, reassess often." Haloperidol 0.5 mg IV with QTc monitoring is the standard answer for the agitated elderly postop patient pulling lines; for the hypoactive patient, no antipsychotic is indicated.

Board pearl: Benzodiazepines for postoperative delirium = wrong answer unless the cause is withdrawal.

Cardinal rule: Pharmacotherapy treats dangerous agitation, not delirium itself. The therapeutic targets are (1) safety of patient/staff, (2) ability to deliver essential care, (3) treating the underlying cause.

Step 1 — Treat the cause first:

Step 2 — Nonpharmacologic de-escalation: familiar voice, family presence, lights on, reorientation, verbal redirection.

Step 3 — When agitation threatens safety (and only then):

Atypical antipsychotics (alternatives, similar efficacy, often better tolerated):

Avoid (worsen or prolong delirium):

Special scenarios:

Expanded Pharmacology and Procedural Considerations

— α2-agonist; provides sedation without respiratory depression; reduces delirium incidence and duration in cardiac surgery and ICU

— Useful for: agitated intubated patients, weaning from ventilator, severe agitation refractory to antipsychotics

— Watch for bradycardia and hypotension; loading dose often skipped

— Reasonable in non-intubated delirious patients in monitored settings at low infusion rates

— Some evidence for prevention (3 mg melatonin or 8 mg ramelteon nightly perioperatively) in high-risk elderly

— Not first-line treatment once delirium is established, but reasonable for sleep restoration component of bundle

— Scheduled acetaminophen 650–1000 mg q6h (cap 3 g/day in elderly/hepatic)

— Regional anesthesia and nerve blocks (fascia iliaca for hip fracture, TAP block for abdominal surgery, epidural for thoracic)

— Gabapentinoids: modest opioid sparing but sedating in elderly and renally dosed — use cautiously

— Avoid NSAIDs in elderly with CKD, CHF, GI bleeding risk

— If opioid required: oxycodone, hydromorphone, or low-dose morphine; avoid meperidine and tramadol (serotonergic, anticholinergic, lowers seizure threshold)

— Remove unnecessary tethers: Foley, telemetry, CVC, restraints — each is an independent delirium risk

— Avoid physical restraints; they worsen agitation and cause injury. If absolutely needed for safety, time-limited order, documented indication, reassessed q2h, with a plan to remove

— Sitter/1:1 observation preferred over restraints

— Consider transfer to a geriatric or ACE (Acute Care for Elders) unit if available

— Diphenhydramine → melatonin or trazodone 25 mg

— Oxybutynin → behavioral bladder strategies or mirabegron

— TCAs → SNRI or duloxetine

— H2 blockers (ranitidine, famotidine high dose) → PPI short-term

— Long-acting benzodiazepines → taper, don't abruptly stop

CCS pearl: Order "discontinue Foley," "discontinue diphenhydramine," "scheduled acetaminophen," "PT consult," and "geriatrics consult" early — these are the high-value, low-risk moves that match real Step 3 grading logic.

Dexmedetomidine — the perioperative star:

Melatonin and ramelteon:

Pain management — opioid-sparing multimodal is delirium-sparing:

Procedural and device considerations:

Drugs to stop or substitute (Beers Criteria highlights):

Special Populations — Elderly and Renal/Hepatic Impairment

— Pharmacokinetic shifts: decreased lean body mass (↑ Vd for lipophilic drugs like benzos), decreased renal/hepatic clearance, increased BBB permeability, decreased cholinergic reserve

— Pharmacodynamic shifts: heightened sensitivity to anticholinergics, opioids, benzodiazepines, and antipsychotics at any dose

— Dose antipsychotics at 25–50% of adult dose: haloperidol 0.25–0.5 mg, quetiapine 12.5 mg

— Apply Beers Criteria before every new prescription

— Screen with Mini-Cog or MoCA preoperatively; involve geriatrics co-management for hip fractures (reduces delirium and mortality)

— Morphine active metabolites (M6G) accumulate → use hydromorphone or fentanyl preferentially

— Meperidine absolutely contraindicated (normeperidine accumulates → delirium, seizures)

— Gabapentin/pregabalin require renal dose adjustment — overdose causes profound sedation and delirium

— Lithium, digoxin, H2 blockers accumulate → check levels, reduce dose

— Watch for uremic encephalopathy as cause of delirium (BUN typically >100, asterixis, may need urgent dialysis)

— Hepatic encephalopathy mimics or precipitates postop delirium — check ammonia, treat with lactulose ± rifaximin, look for trigger (GI bleed, infection, electrolyte shift, sedatives)

— Avoid benzodiazepines; if essential, use lorazepam or oxazepam (no oxidative hepatic metabolism)

— Reduce acetaminophen to ≤2 g/day in cirrhosis

— Albumin shifts → free fraction of highly protein-bound drugs (phenytoin, warfarin) increases — adjust dosing

— Each additional medication >5 increases delirium risk

— Perform medication reconciliation on admission, after surgery, and at discharge

— Use STOPP/START criteria; deprescribe anticholinergics, benzos, sedative-hypnotics

Key distinction: Uremic encephalopathy (BUN ↑↑, asterixis, responds to dialysis) vs hepatic encephalopathy (ammonia ↑, asterixis, responds to lactulose) vs opioid toxicity (pinpoint pupils, responds to naloxone) — all present as "postop delirium" but the treatments diverge.

Board pearl: A cirrhotic patient who becomes confused on POD 2 after upper GI bleed surgery — think hepatic encephalopathy from GI bleed; start lactulose, don't reach for haloperidol first.

Elderly (≥65) — the index population for postoperative delirium:

Renal impairment:

Hepatic impairment:

Polypharmacy and deprescribing:

Special Populations — Other Demographic Subgroups

— Occurs in 10–30% of children after general anesthesia, peaks ages 2–6, most common with sevoflurane or desflurane

— Presents within 30 min of emergence: inconsolable crying, thrashing, non-purposeful movement, lack of eye contact — typically self-limited (<30 min)

— Prevention: propofol bolus at end of case, intraoperative dexmedetomidine, fentanyl, ketamine, or midazolam premedication; parental presence on emergence

— Treat with reassurance, parent at bedside; if severe, propofol 1 mg/kg or dexmedetomidine 0.5 mcg/kg IV

— Key distinction from pain: emergence delirium resolves with sedation but not analgesics alone; pain typically responds to opioid; both can coexist

— Rare but possible after cesarean, especially with eclampsia, severe preeclampsia, hemorrhage, or postpartum psychosis

— Rule out eclampsia, PRES, cerebral venous thrombosis, amniotic fluid embolism before labeling as delirium

— Avoid teratogenic agents if breastfeeding; haloperidol is generally compatible if needed

— Delirium superimposed on dementia (DSD) affects up to 90% of demented postop patients

— Higher baseline → easier to miss the acute change; ask family for baseline daily function

— Quetiapine preferred in Lewy body dementia and Parkinson disease dementia (lower EPS risk)

— Avoid antipsychotics if possible — black-box mortality warning is especially relevant

— Alcohol use disorder: screen with AUDIT-C preoperatively; prophylactic thiamine + folate + CIWA protocol; benzodiazepines are appropriate here

— Chronic opioid users: maintain baseline opioid (do not stop methadone/buprenorphine); add multimodal for acute pain; expect tolerance

— Benzodiazepine-dependent: continue home dose perioperatively to prevent withdrawal-induced delirium

— Highest incidence (up to 80%); CABG and valve surgery especially

— ABCDEF bundle in ICU: Assess pain, Both spontaneous awakening + breathing trials, Choice of sedation, Delirium monitoring, Early mobility, Family engagement

Board pearl: A child who wakes thrashing from sevoflurane anesthesia has emergence delirium, not pain — give propofol or dexmedetomidine, not more fentanyl.

Pediatrics — emergence delirium:

Pregnancy and postpartum:

Patients with dementia:

Substance use populations:

ICU and cardiac surgery patients:

Complications and Adverse Outcomes

— Falls with fractures, head injury, intracranial hemorrhage (especially anticoagulated patients)

— Self-extubation, dislodged CVCs, NG/Foley removal → procedure repetition, infection, bleeding

— Aspiration pneumonia from impaired swallowing and altered consciousness

— Pressure injuries from immobility and agitation alternating with hypoactivity

— Medication errors from changing mental status, refusing meds, or behavioral escalation

— Prolonged hospital length of stay (average +2–5 days) and higher readmission

— QTc prolongation → torsades — check ECG before haloperidol, monitor K and Mg

— Extrapyramidal symptoms (acute dystonia, akathisia, parkinsonism) — treat dystonia with benztropine or diphenhydramine (cautiously)

— Neuroleptic malignant syndrome — fever, rigidity, autonomic instability, elevated CK; stop antipsychotic, supportive care, dantrolene/bromocriptine

— Increased mortality in elderly dementia patients (black-box)

— Aspiration from sedation

— Persistent cognitive impairment — delirium is associated with accelerated cognitive decline; up to 40% have persistent deficits at 6 months

— Functional decline — many never return to baseline ADL/IADL function; higher rates of new nursing home placement

— Post-ICU syndrome when delirium occurred in ICU: PTSD, depression, executive dysfunction

— 2-fold increase in 6-month and 1-year mortality independent of comorbidity

— Hypoactive delirium has the worst prognosis (often unrecognized, longer duration)

— Estimated $164 billion/year in US attributable costs

— Quality metric in Medicare value-based purchasing; tied to hospital-acquired condition penalties

Key distinction: NMS (rigidity, fever, antipsychotic exposure, CK ↑↑) vs serotonin syndrome (clonus, hyperreflexia, serotonergic drug, often hours after dose change) vs anticholinergic toxicity (hot, dry, red, mad — "mad as a hatter") — all can mimic agitated delirium with autonomic instability.

Board pearl: Postoperative delirium is not benign — its mortality signal rivals that of MI. Treat the underlying cause aggressively.

Short-term in-hospital complications:

Antipsychotic-related complications:

Functional and cognitive consequences:

Mortality:

Healthcare system burden:

When to Escalate Care — ICU, Consults, and Inpatient Triage

— Refractory agitation requiring continuous IV sedation (dexmedetomidine drip)

— Airway compromise from sedation or aspiration

— Hemodynamic instability from precipitant (sepsis, MI, PE, GI bleed)

— Status epilepticus including NCSE

— Severe alcohol withdrawal (DTs) with autonomic instability or refractory to PRN benzos

— Suspected NMS, serotonin syndrome, malignant hyperthermia

— QTc >500 ms on antipsychotics

— Recurrent falls requiring sitter and frequent reassessment

— New atrial fibrillation with RVR contributing to delirium

— Geriatrics: all patients ≥75 with delirium, all hip fractures (co-management reduces delirium and mortality)

— Psychiatry / consult-liaison: persistent delirium >5 days, complex agitation, antipsychotic management, when diagnosis is unclear (delirium vs primary psychiatric)

— Neurology: focal deficits, suspected NCSE, persistent encephalopathy despite resolved precipitants

— Palliative care: terminal delirium, goals-of-care discussions in frail elderly

— Addiction medicine: complex withdrawal, substance use disorder co-management

— PT/OT: every delirium patient — early mobilization is therapeutic

— Pharmacy: medication reconciliation, deprescribing review

— Identifiable reversible cause being treated

— Safe with 1:1 sitter or family presence

— Vitals stable, eating/drinking, mobilizing

— Family engaged and informed

— Return to baseline cognition or stable trajectory toward baseline

— Safe disposition (home with caregiver vs SNF vs rehab)

— Medication list reconciled and deliriogenic drugs removed

— Follow-up arranged within 7–14 days

— CAM-negative for ≥24 h ideally before discharge home

Step 3 management: Do not discharge a still-delirious patient home alone. Step 3 loves the answer "arrange skilled nursing facility / inpatient rehab with cognitive monitoring" when the patient is improving but not yet baseline and lives alone.

CCS pearl: Early geriatrics consult on a hip fracture case is a high-yield order — it changes both the case score and real outcomes.

ICU transfer triggers:

Stepdown / telemetry indications:

Consults — who to call and when:

Floor management adequate when:

Discharge readiness criteria (do not rush):

Key Differentials — Same-Category (Encephalopathy) Causes

— Hypoglycemia: sudden onset, diaphoresis, focal deficits possible; fingerstick is the screen — give D50 immediately

— Hyponatremia: especially SIADH after surgery, hypotonic IV fluids, thiazides; lethargy, seizures if Na <120

— Hypernatremia: dehydration in elderly with impaired thirst; agitation, hyperreflexia

— Hypercalcemia: "stones, bones, groans, psychic overtones" — malignancy, hyperparathyroid

— Uremia: asterixis, myoclonus, BUN typically >100; treat with dialysis

— Hepatic encephalopathy: asterixis, ammonia ↑, often triggered by GI bleed/infection/diuretics

— Hypercapnia (CO2 narcosis): COPD, OSA, opioids; ABG diagnostic

— Hypoxia: any cause — pneumonia, PE, atelectasis, CHF

— Thyroid storm / myxedema coma: check TSH, free T4

— Adrenal crisis: especially patients on chronic steroids without perioperative stress dose

— Wernicke encephalopathy: triad of ophthalmoplegia + ataxia + confusion in malnourished/alcoholic; give thiamine before glucose

— Sepsis-associated encephalopathy: delirium often precedes overt sepsis signs in elderly

— UTI, pneumonia, surgical site infection, C. difficile, line infection, meningitis

— Anticholinergic toxicity (mad, hot, dry, red, blind, bowel-and-bladder shutdown)

— Opioid toxicity (pinpoint pupils, hypopnea, somnolence) — naloxone

— Serotonin syndrome (clonus, hyperreflexia, autonomic instability)

— Benzodiazepine intoxication (slurred speech, ataxia, miosis variable)

— Withdrawal syndromes: alcohol, benzo, opioid, nicotine — all can present as delirium

— Steroid psychosis (high-dose prednisone)

— Lithium, digoxin, antiepileptic toxicity — check levels

Key distinction: Alcohol withdrawal (POD 2–4, tremor, tachycardia, hypertension, hyperthermia, hyperreflexia, hallucinations) requires benzodiazepines, the one delirium scenario where they are first-line. Standard postop delirium = avoid benzos.

Board pearl: Always check glucose, sodium, oxygen, and a medication list before anything else — these four catch most reversible mimics.

Metabolic encephalopathies — most common mimics and overlapping causes:

Infection-driven encephalopathy:

Drug-induced encephalopathy:

Key Differentials — Other-Category Causes

— Ischemic stroke or TIA: focal signs key; posterior circulation strokes can mimic delirium without obvious lateralizing findings (consider in cardiac surgery, AFib, hypotension)

— Intracranial hemorrhage: especially in anticoagulated, falls, head trauma; new headache, focal signs, anisocoria

— Subdural hematoma: elderly with falls, may be subacute (days to weeks), waxing/waning — classic mimic

— Seizure / postictal state / NCSE: consider if witnessed event, persistent altered mental status, history of seizures

— PRES (posterior reversible encephalopathy): hypertension, eclampsia, immunosuppression; headache, vision changes, seizures

— Meningitis/encephalitis: fever, neck stiffness, photophobia; LP indicated

— Silent MI in elderly/diabetic — get ECG and troponin

— Pulmonary embolism — hypoxia, tachycardia, hypotension, syncope

— Pulmonary edema / acute heart failure — orthopnea, hypoxia, rales

— Cardiac tamponade post-cardiac surgery — Beck triad, pulsus paradoxus

— Anastomotic leak (abdominal surgery) — fever, tachycardia, peritonitis, sepsis-driven delirium POD 3–7

— Postoperative bleeding — hypovolemic shock, anemia

— Compartment syndrome — orthopedic, vascular surgery

— Cerebral hyperperfusion syndrome after CEA — headache, seizures, delirium days postop

— Fat embolism syndrome after long bone fracture/repair — petechiae, hypoxia, delirium 24–72 h postop

— Major depression (especially in hypoactive presentations) — stable affect over time, intact attention, longer onset

— Acute psychosis — usually in patients with known psychiatric history; preserved attention

— Catatonia — can be mistaken for hypoactive delirium; lorazepam challenge is both diagnostic and therapeutic

— Conversion / functional disorder — last resort, after thorough workup

Key distinction: Subdural hematoma in elderly post-fall is the great mimic — waxing/waning over days, often without focal signs. Low threshold for non-contrast head CT in any anticoagulated or fallen elderly patient with new confusion.

Board pearl: A POD 3 abdominal surgery patient with new tachycardia, mild fever, and confusion = anastomotic leak until proven otherwise, not "just delirium."

Neurologic — structural and electrical:

Cardiopulmonary catastrophes presenting as delirium:

Surgical complications specific to the procedure:

Psychiatric mimics — diagnoses of exclusion:

Secondary Prevention, Discharge Medications, and Long-Term Plan

— Stop or substitute deliriogenic drugs added during admission: diphenhydramine, scopolamine patches, meperidine, high-dose anticholinergic bladder agents

— Taper antipsychotics started for delirium — do not discharge on chronic haloperidol or quetiapine unless there is a separate psychiatric indication. Plan taper over 1–2 weeks and document the stop date

— Reduce or eliminate benzodiazepines and z-drugs; substitute behavioral sleep strategies, melatonin, or trazodone 25–50 mg if pharmacologic agent truly needed

— Reassess each Beers Criteria drug at discharge

— Pain: scheduled acetaminophen, taper opioids to lowest effective dose, plan to discontinue within days–weeks

— Bowel regimen with any opioid (senna ± PEG)

— DVT prophylaxis as appropriate for surgery

— Resume home medications carefully; do not reflexively restart all preadmission psychotropics if delirium revealed they were contributing

— Inform patient and family: an episode of postoperative delirium increases risk of long-term cognitive decline and future delirium

— Recommend baseline cognitive testing at follow-up (MoCA) and repeat at 3–6 months

— Encourage cognitive engagement, physical activity, social interaction, hearing/vision correction, treatment of depression

— Address modifiable dementia risk factors (Lancet commission): hypertension, hearing loss, diabetes, smoking, depression, social isolation, physical inactivity

— Document the episode prominently in the chart and discharge summary

— Flag for future preoperative evaluation: high-risk patient needing prevention bundle, regional anesthesia preference, avoidance of specific drugs

— Advance care planning conversation while patient is at baseline — surrogate decision-maker, code status, goals of care

— Warning signs of recurrence, when to call, fall prevention at home, medication safety, hearing aids/glasses use

Step 3 management: A patient discharged on a new antipsychotic from a delirium admission needs a specific taper plan and follow-up — leaving them on chronic haloperidol is a quality and safety failure tested directly on Step 3.

Board pearl: Document the delirium episode in the problem list — it should travel with the patient to every future encounter.

Reconcile and deprescribe before discharge — every time:

Discharge medication list essentials:

Long-term cognitive trajectory counseling:

Future surgery planning ("delirium passport"):

Caregiver education:

Follow-Up, Monitoring, and Rehabilitation Plan

— PCP visit within 7–14 days of discharge — review medications, cognitive status, functional recovery, mood

— Surgical follow-up per procedure (typically 2 weeks)

— Geriatrics or cognitive clinic referral at 4–6 weeks if persistent symptoms or significant baseline cognitive concern

— Repeat MoCA at 3 and 6 months to track recovery; persistent decline warrants formal dementia workup

— Cognition: MoCA score trajectory; ask family about ADLs/IADLs (driving, finances, medications, cooking)

— Mood: PHQ-9 — depression is common after delirium and amplifies cognitive complaints

— Sleep: persistent insomnia or hypersomnia

— Function: gait, balance, falls history (use Timed Up and Go; >12 sec = elevated fall risk)

— Medication adherence and side effects, especially if antipsychotic still being tapered

— Hearing and vision — confirm aids are being used

— Home health PT/OT for first 2–4 weeks post-discharge

— Inpatient rehab or SNF if not at functional baseline at discharge — better outcomes than premature home discharge

— Outpatient cognitive rehabilitation for persistent deficits

— Pulmonary rehab if delirium was driven by hypoxic event

— Normalize the experience but emphasize it is not "just old age" — it signals brain vulnerability

— Discuss future surgery precautions and the delirium passport

— Address caregiver burden — family of delirium survivors have elevated depression and anxiety; screen and refer

— Driving safety conversation if cognitive deficits persist; formal driving evaluation if uncertain

— Hospitals track delirium as a quality metric; participation in HELP or NICHE programs reduces incidence

— Document delirium in problem list and discharge summary so it informs future care (continuity of care)

— Value-based care: preventing readmission within 30 days is the key system-level target

CCS pearl: Order "MoCA at follow-up," "PT/OT home health," "PCP follow-up in 7–10 days," and "geriatrics referral" — these match both Step 3 scoring and good real-world practice.

Board pearl: A patient who "never returned to normal" after surgery may have undiagnosed dementia unmasked by delirium — formal evaluation at 3–6 months is the right move.

Follow-up cadence:

Monitoring parameters at follow-up:

Rehabilitation services:

Counseling — patient and family:

Quality and population-health considerations:

Ethical, Legal, and Patient Safety Considerations

— A delirious patient lacks capacity for medical decisions — capacity is decision-specific and fluctuates with delirium

— Identify and engage the healthcare proxy / surrogate decision-maker for non-emergent decisions; use state-specific surrogate hierarchy if no proxy

— For emergencies, proceed under implied consent / emergency exception and document

— Reassess capacity each day — many patients regain it as delirium resolves; defer non-urgent decisions when possible

— Preoperative discussion: in high-risk elderly, discuss delirium risk during consent for surgery and document

— If the patient discussed preferences before surgery, those govern during incapacity

— Revisit code status with surrogate if clinical course changes; do not assume prior DNR is invalidated by surgery (the "surgical DNR suspension" should be an explicit, time-limited, documented discussion preoperatively)

— Restraints (chemical or physical) require documented indication of imminent danger, time-limited orders (typically 4 h for adults, less for behavioral), face-to-face evaluation within 1 hour, and frequent reassessment

— Use least restrictive alternative: sitter, family presence, environmental modifications first

— Document why alternatives were inadequate

— New confusion in an elderly patient with bruises, dehydration, or unexplained injury → consider elder abuse and report per state law

— Falls with injury in hospital may be reportable serious events (sentinel events)

— Medication reconciliation at every transition (admission, ICU/floor, discharge) — delirium-driving drugs frequently get carried forward inadvertently

— Communicate cognitive status to receiving team/facility in writing — a delirious patient sent to SNF without that information is a sentinel safety event

— Schedule PCP follow-up before discharge, not "in the next few weeks"

— Provide written instructions in patient's preferred language at appropriate health literacy level; verify caregiver understanding using teach-back

— Errors (wrong drug, fall, restraint injury) require transparent disclosure to patient/family and incident reporting

Step 3 management: When the exam asks who makes decisions for a delirious postoperative patient without an advance directive, the answer is the surrogate per state hierarchy (typically spouse → adult children → parents → siblings) — not the surgeon, not the ethics committee unless conflict exists.

Board pearl: Chemical restraint requires the same documentation and safeguards as physical restraint — "just give haloperidol" is not a free pass.

Informed consent and decisional capacity:

Advance directives and code status:

Restraints — legal and ethical guardrails:

Mandatory reporting and abuse:

Transition-of-care safety — a major Step 3 theme:

Disclosure and quality reporting:

High-Yield Associations and Rapid-Fire Clinical Facts

— POD 0–1: hypoxia, hypoglycemia, residual anesthetic, hypotension

— POD 2–4: alcohol/benzo withdrawal, UTI, pneumonia, opioid accumulation, MI

— POD 3–7: anastomotic leak, PE, DVT, SSI

— Late: C. diff, sepsis, deconditioning

Board pearl: If the question stem mentions an elderly patient, recent surgery, and a new sedating medication (especially diphenhydramine for sleep), the answer is almost always "discontinue the offending drug."

Surgery types with highest delirium risk: hip fracture > cardiac (CABG, valve) > major vascular > major abdominal > thoracic

Anesthesia: regional/neuraxial reduces delirium vs general in hip fracture (modest effect); BIS-guided lighter anesthesia depth reduces delirium in elderly

POD timing classics:

Drug "do-nots" in elderly perioperative care: diphenhydramine, meperidine, scopolamine, oxybutynin, long-acting benzos (diazepam, flurazepam), TCAs

Drug "do-okays": acetaminophen, oxycodone (low dose), hydromorphone, fentanyl, regional blocks, melatonin, trazodone (low dose), dexmedetomidine

Wernicke prevention: thiamine 100 mg IV before glucose in any malnourished, alcoholic, or hyperemesis patient

CAM = gold standard bedside tool; CAM-ICU for ventilated patients; 4AT for rapid screening

HELP program (Hospital Elder Life Program): reduces delirium incidence ~40%, cost-effective

Dexmedetomidine reduces delirium in cardiac surgery and ICU vs benzodiazepine sedation

Antipsychotic black-box warning: increased mortality in elderly dementia patients — does not prohibit use but mandates lowest dose, shortest duration, documented indication

QTc threshold: hold antipsychotic if QTc >500 ms; correct K and Mg before redosing

Lewy body / Parkinson disease dementia: avoid haloperidol and typical antipsychotics → use quetiapine or pimavanserin

Alcohol withdrawal: symptom-triggered benzos (CIWA), thiamine, magnesium; phenobarbital or propofol for refractory DTs

Catatonia mimicker of hypoactive delirium: lorazepam 1–2 mg IV challenge is diagnostic and therapeutic

Postoperative cognitive dysfunction (POCD) is distinct from delirium — subtler, longer-lasting cognitive decline detected on neuropsych testing, weeks to months postop

Sleep: any single night of severe sleep disruption can precipitate delirium in vulnerable elderly — protect sleep aggressively

Family presence at bedside is one of the strongest nonpharmacologic interventions

Hearing and vision aids at the bedside reduce delirium incidence — order this as if it were a medication

Board Question Stem Patterns

— 82-year-old POD 2 after hip ORIF becomes confused and agitated overnight, pulling at IV. → Look for and treat reversible cause (bladder scan, glucose, electrolytes, pain, oxygenation, medication review) BEFORE pharmacologic restraint. Wrong answers: haloperidol, lorazepam, physical restraint, head CT.

— 78-year-old scheduled for elective hip replacement, lives alone, MoCA 24. → Multicomponent nonpharmacologic intervention (HELP bundle). Wrong answers: prophylactic haloperidol, donepezil, melatonin alone, cancel surgery.

— Elderly patient on multiple meds becomes confused after starting a sleep aid. Likely culprit: diphenhydramine (anticholinergic). Other classics: meperidine, benzodiazepines, oxybutynin, scopolamine.

— POD 2 hip fracture, BP 168/95, HR 115, tremulous, diaphoretic, anxious, mild fever. → Alcohol withdrawal — give lorazepam (CIWA-triggered) and thiamine. The one scenario benzodiazepines are correct.

— Elderly POD 3 patient described as "quiet, sleepy, not eating, minimal interaction." → Recognize as hypoactive delirium, not depression; order CAM and reversible-cause workup.

— Patient with Parkinson disease/Lewy body dementia and postop agitation. → Quetiapine (avoid haloperidol — severe EPS, neuroleptic sensitivity).

— Postop confusion with focal deficit, fall with head strike, anticoagulated, or papilledema → non-contrast head CT. Routine confusion without focal signs → not indicated initially.

— Delirium not resolving after 72 h despite reversal of obvious causes → consider NCSE (EEG), occult stroke (MRI), undertreated withdrawal, or new infection (e.g., C. diff).

— Improving but not at baseline, lives alone → SNF or inpatient rehab, not home alone.

— Delirious patient refuses essential treatment → lacks capacity; engage surrogate. Emergency → implied consent.

— Patient stabilized on quetiapine for delirium → plan taper and discontinuation, not lifelong therapy.

— Started haloperidol → ECG for QTc, check K and Mg.

Step 3 management: When two answers seem reasonable, pick the one that treats the cause or removes a deliriogenic drug over the one that adds a new medication.

Board pearl: "Reorientation, family at bedside, glasses and hearing aids, and discontinue diphenhydramine" beats "haloperidol 2 mg IV" on the exam — every time.

Pattern 1 — "Best initial step":

Pattern 2 — "Best preventive strategy":

Pattern 3 — "Drug to avoid":

Pattern 4 — "Identify the precipitant":

Pattern 5 — "Hypoactive delirium":

Pattern 6 — "Antipsychotic selection":

Pattern 7 — "When to image":

Pattern 8 — "Persistent delirium":

Pattern 9 — "Disposition":

Pattern 10 — "Capacity":

Pattern 11 — "Discharge medication":

Pattern 12 — "Best monitoring":

One-Line Recap

Postoperative delirium is an acute, fluctuating, attention-centered brain failure that is prevented with multicomponent nonpharmacologic bundles, diagnosed by CAM, managed by aggressively identifying and reversing precipitants while avoiding deliriogenic drugs, and treated pharmacologically only when agitation threatens safety.

— HELP-style bundle (reorientation, sensory aids, mobility, sleep, hydration, pain control without benzos/anticholinergics) reduces incidence ~40%

— Identify high-risk patients preoperatively with Mini-Cog/MoCA; consider regional anesthesia and BIS-guided depth

— Avoid benzodiazepines, diphenhydramine, meperidine, scopolamine, and oxybutynin in elderly perioperative patients

— CAM = acute onset/fluctuation + inattention + (disorganized thinking OR altered LOC)

— Hypoactive subtype is most common and most missed — screen actively

— First-line workup: glucose, BMP, Mg/Phos, CBC, UA, CXR, ECG, ABG, bladder scan, medication reconciliation; imaging and EEG reserved for focal signs or refractory cases

— Treat the cause first; nonpharmacologic de-escalation second

— Low-dose haloperidol (0.25–0.5 mg) or quetiapine for dangerous agitation only; monitor QTc; avoid haloperidol in Parkinson/Lewy body

— Benzodiazepines are correct only for alcohol/benzo withdrawal, seizure, NMS, or serotonin syndrome

— Dexmedetomidine for ICU sedation reduces delirium vs benzodiazepines

— Reconcile and deprescribe at every transition; taper any antipsychotic started for delirium with a defined stop date

— Document the episode in the problem list — delirium history changes future perioperative planning

— Address capacity, surrogate decision-making, restraint safeguards, and follow-up cognitive assessment at 3–6 months

— A delirium episode doubles 1-year mortality and accelerates cognitive decline — treat it as the high-stakes event it is

Board pearl: When in doubt on Step 3, the right move for postoperative delirium is almost always to stop a drug, fix a metabolic problem, and call the family to the bedside — not to add a new sedative.

Prevention >> Treatment:

Diagnosis is clinical, workup hunts the cause:

Pharmacotherapy is narrow:

Transitions and long-term plan matter: