Nervous System & Special Senses

Delirium: workup and management in hospitalized adults

Clinical Overview and When to Suspect Delirium

— Prevalence 15–25% on general medical wards, 50–75% in ICU, up to 80% post-cardiac surgery, and ~50% in hip fracture patients.

— Independently associated with increased mortality, prolonged length of stay, higher rates of institutionalization, and accelerated cognitive decline.

— Any hospitalized patient ≥65, with baseline cognitive impairment, severe illness, postoperative day 0–3, ICU admission, or after sedation/anesthesia.

— Screen at admission, every nursing shift in high-risk units, and whenever a new behavioral/cognitive change is reported (often by family or nurse: "he's not himself today").

— CAM (Confusion Assessment Method): positive if (1) acute onset + fluctuating course AND (2) inattention, PLUS either (3) disorganized thinking OR (4) altered level of consciousness.

— CAM-ICU and ICDSC for intubated/non-verbal ICU patients.

— 4AT: alertness, AMT4, attention (months backward), acute change — score ≥4 = possible delirium.

— Hyperactive (~25%): agitation, hallucinations — easy to recognize.

— Hypoactive (~50%): lethargy, withdrawal — most missed, worst prognosis.

— Mixed (~25%): fluctuates between both.

Board pearl: A "quiet, sleepy, withdrawn" elderly inpatient who "isn't causing problems" is the classic hypoactive delirium stem — the right answer is to screen with CAM, not to reassure the family.

Definition: Delirium is an acute, fluctuating disturbance of attention and awareness with additional cognitive change (memory, orientation, language, visuospatial, perception) that is not better explained by a pre-existing or evolving dementia, develops over hours to days, and is the direct physiologic consequence of a medical condition, substance, or withdrawal (DSM-5-TR criteria).

Epidemiology in hospitalized adults:

When to actively screen:

Validated bedside tools:

Subtypes:

Presentation Patterns and Key History

— Acute onset over hours–days with a fluctuating course (lucid intervals alternating with confusion, often worse at night → "sundowning").

— Inattention: can't follow a conversation, perseverates, miscounts months/days of week backward, can't sustain digit span.

— Disorganized thinking: tangential, illogical, rambling speech.

— Altered arousal: hypervigilant or somnolent; normal alertness essentially rules out delirium at that moment.

— Perceptual disturbances: visual hallucinations, illusions (more than auditory — opposite of primary psychosis).

— Reversed sleep–wake cycle, emotional lability.

— Always obtain collateral from family/SNF/primary team — establish the patient's baseline cognition and functional status within the last 1–2 weeks.

— Timeline of mental status change relative to admission, medication changes, procedures, infection symptoms.

— Targeted review: fever, dysuria, cough, abdominal pain, constipation, urinary retention, pain control, recent falls, head trauma.

— New or changed medications, especially anticholinergics (diphenhydramine, oxybutynin, TCAs), benzodiazepines, opioids (meperidine!), corticosteroids, fluoroquinolones, H2 blockers.

— Substance use/withdrawal: alcohol, benzodiazepines, opioids, nicotine, cannabis, stimulants — last use date and time.

— Environmental: ICU, restraints, tethers (Foley, telemetry, IVs), sensory deprivation (no glasses/hearing aids), sleep disruption.

Key distinction: Delirium = acute, fluctuating, with inattention; dementia = chronic, progressive, attention often preserved early. Stems that include "over the past 2 days" + "fluctuates" + "family says she was fine last week" are delirium until proven otherwise.

Hallmark features (must be elicited deliberately):

History — sources and targets:

High-yield precipitants to actively ask about:

Predisposing factors (the substrate): age ≥65, baseline dementia, frailty, multiple comorbidities, polypharmacy, sensory impairment, prior delirium, alcohol use disorder, depression.

Physical Exam Findings and Hemodynamic Assessment

— Temperature (occult infection; hypothermia in sepsis or hypothyroidism).

— HR/BP: tachycardia + hypertension + diaphoresis + tremor → alcohol/benzo withdrawal; hypotension → sepsis, hemorrhage, dehydration, adrenal insufficiency.

— RR and SpO2: hypoxia and hypercapnia are reversible delirium causes — always check an ABG/VBG if any pulmonary disease.

— Glucose: fingerstick at bedside immediately — hypoglycemia and DKA both cause delirium.

— Level of arousal (RASS), attention testing (months backward, serial 7s, digit span).

— Focal deficits — facial droop, hemiparesis, aphasia, neglect, gaze deviation — mandate emergent neuroimaging (stroke, hemorrhage, mass).

— Pupils: pinpoint → opioid; dilated → anticholinergic, sympathomimetic, withdrawal.

— Asterixis → hepatic/uremic/CO2 encephalopathy.

— Myoclonus + hyperreflexia + clonus → serotonin syndrome or uremia.

— Rigidity + hyperthermia + autonomic instability → NMS.

— Nuchal rigidity → meningitis (less reliable in elderly — low threshold for LP).

— Dry, flushed, hyperthermic, mydriasis, urinary retention = anticholinergic toxidrome ("hot as a hare…").

— Diaphoresis, piloerection → withdrawal.

— Jaundice → hepatic encephalopathy.

— Lungs (pneumonia), abdomen (tenderness, distention, bladder scan for retention), rectal (impaction, GI bleed), lines/wounds/skin (cellulitis, pressure ulcers, IV phlebitis), Foley site.

Step 3 management: First three bedside actions in any new inpatient delirium → fingerstick glucose, full vital signs (including SpO2 and temperature), and a bladder scan, before ordering any imaging or psychoactive medication.

General and vitals — the "delirium vital sign sweep":

Neurologic exam (focus on what changes management):

Skin/mucous membranes:

Targeted system search for the precipitant (the "DELIRIUMS" sweep):

Diagnostic Workup — Initial Labs, Imaging, ECG

— CBC with differential (leukocytosis/leukopenia → infection; anemia → hypoxia/bleed).

— CMP: glucose, Na (hypo-/hypernatremia), Ca, BUN/Cr (uremia, AKI), LFTs (hepatic encephalopathy), bicarbonate (anion gap).

— Mg, phosphate — especially in alcohol use, refeeding, diuretic use.

— TSH if chronic risk factors or no obvious cause.

— UA + urine culture — but avoid anchoring on "UTI" from asymptomatic bacteriuria in elderly; require pyuria + symptoms or no other cause.

— Blood cultures ×2 if febrile, hypothermic, or hemodynamically off.

— Troponin, BNP if chest symptoms, tachycardia, or hypoxia — silent MI/CHF commonly present as delirium in elderly.

— VBG/ABG with lactate if tachypnea, hypoxia, sepsis suspicion.

— Look for silent ischemia, new AF with RVR, QTc prolongation (relevant before starting haloperidol/antipsychotics).

— Baseline QTc >500 ms or >60 ms increase = avoid IV haloperidol; favor non-pharmacologic management or low-dose atypical with monitoring.

— Obtain when there is focal neurologic deficit, recent fall/head trauma, anticoagulation, depressed consciousness disproportionate to metabolic findings, suspected stroke/ICH, or no identifiable metabolic/infectious cause after initial workup.

— Yield is low (<10%) when imaging is ordered reflexively without these features.

Board pearl: In a 78-year-old with new confusion, bacteriuria alone ≠ UTI. Treating asymptomatic bacteriuria does not improve delirium and exposes the patient to C. difficile — the IDSA explicitly recommends against this.

Reflex initial labs in every new hospital delirium:

ECG:

CXR: pneumonia, pulmonary edema, effusion — low threshold in any febrile, hypoxic, or aspiration-risk patient.

Neuroimaging (non-contrast head CT) — selective, not routine:

Medication reconciliation as a "test": review every drug given in the last 72 hours including PRNs (diphenhydramine for sleep, oxybutynin, meperidine, Z-drugs).

Diagnostic Workup — Advanced or Confirmatory Studies

— Indicated for fever + altered mental status without clear source, suspected meningitis/encephalitis, immunocompromise, new headache + confusion, or persistent unexplained delirium.

— Send opening pressure, cell count, glucose, protein, Gram stain, culture; add HSV PCR (especially with temporal lobe signs, seizures, focal exam), VDRL/RPR, cryptococcal antigen if immunocompromised.

— Empiric ceftriaxone + vancomycin ± ampicillin (>50 y or immunocompromised) + acyclovir + dexamethasone before LP if imaging delayed.

— Order when nonconvulsive status epilepticus (NCSE) is suspected — unexplained persistent altered consciousness, post-cardiac arrest, post-stroke confusion, subtle twitching, eye deviation, recent seizure.

— Delirium EEG classically shows diffuse background slowing; triphasic waves suggest hepatic/uremic/anoxic encephalopathy.

— MRI brain with diffusion for suspected posterior circulation stroke, encephalitis, PRES, CNS vasculitis, limbic encephalitis (paraneoplastic/autoimmune — anti-NMDA, LGI1).

— CTA/MRA if vascular cause suspected.

— Urine drug screen, serum ethanol, salicylate, acetaminophen levels in suspected ingestion.

— Ammonia (cirrhosis, valproate), cortisol/ACTH stim (adrenal insufficiency), B12, HIV, RPR if subacute or risk factors.

— Carboxyhemoglobin if winter, fuel exposure, multiple household members affected.

Key distinction: Delirium EEG = diffuse slowing; NCSE EEG = continuous epileptiform discharges. If a "delirious" patient doesn't clear despite treatment of obvious metabolic issues, get an EEG before escalating sedation — you don't want to snow a seizing brain.

When initial workup is unrevealing, escalate based on clinical clues:

Lumbar puncture:

EEG:

Advanced neuroimaging:

Toxicology and metabolic deep dive:

Autoimmune/paraneoplastic panel (CSF + serum): when subacute encephalopathy with psychiatric features, seizures, movement disorder, young patient, or refractory presentation.

Risk Stratification and First-Line Management Logic

— Step 1 — Stabilize: ABCs, vitals, glucose, oxygen, IV access.

— Step 2 — Identify precipitants using the mnemonic "DELIRIUM(S)": Drugs, Electrolytes/Endocrine, Lack of drugs (withdrawal), Infection, Reduced sensory input, Intracranial, Urinary/fecal retention, Myocardial/pulmonary, Sleep/pain.

— Step 3 — Address modifiable factors: stop offending drugs, treat infection, correct electrolytes, relieve retention, control pain, restore glasses/hearing aids, mobilize, normalize sleep-wake cycle.

— Step 4 — Non-pharmacologic management first (HELP/ABCDEF bundle).

— Step 5 — Pharmacologic management only for severe agitation threatening safety or interfering with essential care.

— Predisposing × precipitating model: a frail demented patient needs only mild precipitant (one anticholinergic) to develop delirium; a young healthy patient needs a major insult.

— Hypoactive delirium has higher mortality — don't let "calm" mean "untreated."

— Reorientation (clock, calendar, family photos), early mobilization, sleep protocol (no nighttime vitals/meds when possible), vision/hearing aids, hydration, avoid restraints, minimize tethers.

— Assess pain, Both SAT/SBT (spontaneous awakening/breathing trials), Choice of analgesia/sedation (avoid benzos), Delirium monitoring, Early mobility, Family engagement.

Step 3 management: The single highest-yield intervention in established delirium is medication review and deprescribing — discontinue benzodiazepines, anticholinergics, meperidine, Z-drugs, and H2 blockers; convert to safer alternatives.

Mental model: Delirium is a syndrome, not a diagnosis — the management priority is to identify and treat the underlying precipitant(s) while preventing harm. Pharmacotherapy is adjunctive, not curative.

Step-by-step CCS-style approach:

Risk stratification — who decompensates:

HELP (Hospital Elder Life Program) — evidence-based bundle:

ICU equivalent — ABCDEF bundle:

Pharmacotherapy — When and What to Use

— 0.25–0.5 mg PO/IV/IM in elderly, may repeat q30–60 min; 1–2 mg in younger adults. Max 5 mg/24 h in elderly.

— IV preferred for rapid onset; continuous cardiac monitoring required for IV.

— Contraindications/cautions: prolonged QTc (>500 ms), Parkinson disease/DLB (use quetiapine), NMS history, hypokalemia/hypomagnesemia.

— Baseline and follow-up ECG; correct K+/Mg++ before dosing.

— Quetiapine 12.5–25 mg PO BID — preferred in Parkinson disease, DLB (low D2 affinity); sedating, useful for sundowning.

— Risperidone 0.25–0.5 mg PO BID.

— Olanzapine 2.5–5 mg PO/IM — caution with metabolic effects.

— Alcohol/benzodiazepine withdrawal: benzodiazepines are first-line (lorazepam, diazepam) using CIWA-Ar–driven dosing. Add thiamine 100 mg IV before glucose to prevent Wernicke.

— Anticholinergic toxidrome: supportive care; physostigmine only for severe cases (seizures, severe agitation) in monitored setting.

— Opioid withdrawal: clonidine, methadone/buprenorphine.

— Serotonin syndrome: stop offending agents, benzos, cyproheptadine if severe.

— Benzodiazepines (except in withdrawal/seizure), diphenhydramine, meperidine, anticholinergics, Z-drugs (zolpidem).

Board pearl: Black box warning — antipsychotics increase mortality in elderly patients with dementia-related psychosis. Document indication, discuss with family, and plan discontinuation at discharge — never let antipsychotics ride home unnecessarily.

Indication for medication: severe agitation causing harm or preventing essential care (e.g., pulling lines, climbing out of bed, refusing life-saving therapy). No drug treats delirium itself — current evidence (including AGS guidelines) does not support routine antipsychotic use to shorten duration or reduce mortality.

First-line: Haloperidol (typical antipsychotic):

Atypical antipsychotics (equivalent efficacy, sometimes preferred):

Specific scenarios — different drug:

Avoid in delirium (worsen it):

Use lowest effective dose, scheduled rather than PRN cascade, time-limited (24–72 h), daily reassessment for taper.

Non-Pharmacologic Management and Environmental Strategy

— Orientation: visible clock, calendar, daily reorientation by staff, family photos at bedside.

— Sensory optimization: glasses on, hearing aids in with working batteries, dentures in for meals.

— Sleep hygiene: cluster nighttime care, avoid 2–6 AM vitals/blood draws when safe, dim lights, eye masks/earplugs, daytime light exposure, no daytime naps >30 min.

— Mobility: out of bed for meals, ambulate TID, PT/OT consult day 1, sit up for meals — remove tethers (discontinue telemetry, Foley, IV when possible).

— Hydration and nutrition: oral intake monitoring, dentures for meals, swallow evaluation if aspiration risk.

— Pain control: scheduled acetaminophen, non-opioid adjuncts, avoid meperidine; untreated pain itself causes delirium.

— Bowel/bladder: bowel regimen prophylaxis, bladder scan q8h if Foley removed, treat constipation aggressively.

— Single room when possible, consistent nursing staff, family at bedside as "sitters."

— Avoid physical restraints — they paradoxically worsen agitation and injury; use sitter or family presence first.

— Minimize room/bed changes.

— Daily SAT + SBT, target light sedation (RASS 0 to −1), dexmedetomidine or propofol over benzodiazepines when sedation needed.

— Early mobilization within 24–48 h even on the vent.

— Family at bedside, communication boards, eyeglasses.

— Each shift: CAM result, precipitants identified, interventions, response.

CCS pearl: In a CCS case, ordering "reorientation, glasses, hearing aids, sleep protocol, early mobilization, remove Foley, discontinue benzodiazepines" scores more points than ordering haloperidol. Place these orders at admission for any high-risk patient — don't wait for delirium to appear.

Multicomponent non-pharmacologic interventions reduce delirium incidence by ~30–40% — the strongest evidence base in the field (HELP, MIND-USA-style protocols, AGS/NICE guidelines).

The bedside checklist (apply to every at-risk inpatient):

Environmental modifications:

ICU-specific (ABCDEF bundle, repeated for emphasis):

Documentation and handoff:

Special Populations — Elderly and Renal/Hepatic Impairment

— Account for the majority of inpatient delirium; age is the strongest non-modifiable risk factor.

— Pharmacokinetics: ↓ lean body mass → ↑ volume of distribution for lipophilic drugs (benzos, opioids), ↓ renal clearance, ↑ CNS sensitivity. Start at 25–50% of adult dose.

— Beers Criteria drugs to avoid: diphenhydramine, hydroxyzine, benzodiazepines, meperidine, oxybutynin, scopolamine, TCAs, first-gen antihistamines, muscle relaxants, Z-drugs.

— STOPP/START criteria for deprescribing during hospitalization.

— Sensory deprivation huge: 1 in 3 elderly inpatients lack their glasses or hearing aids — request from family within 24 h of admission.

— Affects up to two-thirds of hospitalized patients with dementia. Often missed because baseline cognition is impaired.

— Clue: acute change from documented baseline + new fluctuation + inattention beyond baseline.

— Use DLB protocol (avoid typical antipsychotics) if Parkinsonism, REM sleep behavior disorder, or visual hallucinations predate hospitalization.

— Avoid meperidine (normeperidine accumulates → seizures and delirium).

— Morphine metabolites (M3G, M6G) accumulate → use hydromorphone or fentanyl.

— Gabapentin/pregabalin: dose-reduce; can cause encephalopathy in CKD.

— H2 blockers (especially famotidine, ranitidine) — renally cleared, cause confusion; substitute PPI if needed.

— Adjust haloperidol minimally; lorazepam preferred benzo (no active metabolites) when truly needed.

— Hepatic encephalopathy is the differential — check ammonia, treat with lactulose (titrate to 3 bowel movements/day) + rifaximin; identify trigger (GI bleed, infection, electrolyte, constipation, TIPS).

— Avoid benzodiazepines (except lorazepam, oxazepam, temazepam — glucuronidated, "LOT"). Reduce opioid doses.

Step 3 management: In hospitalized elderly, perform a Beers-based medication review on admission and again at discharge — this is a quality measure and a high-yield exam intervention.

Elderly (≥65):

Dementia + delirium ("delirium superimposed on dementia"):

Renal impairment:

Hepatic impairment:

Special Populations — Postoperative, ICU, Pregnancy, End-of-Life

— Incidence: 15% general surgery, 30–50% hip fracture/cardiac surgery, up to 70% in elderly cardiac surgery.

— Peak: POD 1–3. Risk factors: age, preop cognitive impairment, prolonged anesthesia, intraop hypotension, blood transfusion, pain, anticholinergic burden.

— Prevention: preoperative cognitive screening, multimodal analgesia (acetaminophen, regional anesthesia, opioid-sparing), avoid benzodiazepine premedication, depth-of-anesthesia monitoring (BIS), early mobilization.

— Hip fracture specifically: regional anesthesia (fascia iliaca block), surgery within 24–48 h, geriatric co-management reduces delirium.

— Up to 80% of mechanically ventilated patients. Independent predictor of long-term cognitive impairment ("post-ICU syndrome").

— Sedation choice matters: dexmedetomidine > propofol > benzodiazepines for delirium prevention.

— Daily SAT/SBT, target RASS 0 to −1, early mobility, family presence.

— Rare but consider eclampsia, posterior reversible encephalopathy syndrome (PRES), amniotic fluid embolism, postpartum psychosis, thrombotic events, magnesium toxicity.

— Postpartum psychosis (1–2/1000) is a psychiatric emergency — distinct from delirium but stem may confuse them; postpartum psychosis = onset within 2 weeks, rapid cycling mood/psychosis — admit and treat with antipsychotics + mood stabilizer; assess infanticide/suicide risk.

— Haloperidol relatively safe in pregnancy if antipsychotic needed; avoid benzodiazepines near delivery (neonatal sedation/withdrawal).

— Occurs in 80–90% of dying patients. Goal shifts from full reversal to comfort.

— Treat reversible causes if consistent with goals (opioid rotation, hypercalcemia, urinary retention).

— Haloperidol or chlorpromazine for agitation; midazolam infusion for refractory terminal agitation (palliative sedation), after documented goals-of-care discussion.

Key distinction: Postpartum blues (mild, self-limited, <2 weeks) vs postpartum depression (≥2 weeks, functional impairment) vs postpartum psychosis (psychotic features, emergency, admit) — only the last presents with delirium-like confusion plus psychosis.

Postoperative delirium:

ICU delirium:

Pregnancy and peripartum:

End-of-life ("terminal delirium"):

Complications and Adverse Outcomes

— Falls and fractures — agitated, disoriented patients climb out of bed; delirium triples fall risk.

— Pressure injuries from immobility.

— Aspiration pneumonia from impaired airway protection and altered swallowing.

— Line/tube self-removal — pulled central lines, NG tubes, endotracheal tubes; failed extubations.

— Restraint-related injury: skin breakdown, rhabdomyolysis, asphyxia — restraints are associated with higher, not lower, injury rates.

— Medication injury: oversedation, QTc prolongation/TdP, NMS, EPS, falls from psychotropics.

— Hospital-acquired infections from prolonged stay, lines, catheters.

— Failed procedures and informed consent issues — patients refuse necessary care or cannot consent.

— Delirium adds 5–10 days to LOS and $60,000+ to admission cost per episode; estimated $164 billion/year in US healthcare costs.

— Mortality: 1-year mortality ~35–40% after a delirium episode in elderly; 2-fold increased mortality independent of comorbidities.

— Persistent cognitive decline: delirium accelerates trajectory of dementia and may unmask preclinical dementia; about 40% of post-ICU patients have cognitive impairment at 1 year resembling moderate TBI or mild Alzheimer.

— Functional decline: loss of ADLs, new nursing home placement (~2–3× rate).

— Post-ICU PTSD, depression, anxiety ("PICS — post-intensive care syndrome").

— Persistent delirium: 20% still meet criteria at 6 months.

Board pearl: Delirium is not benign or transient — counsel families that recovery may take weeks to months, and cognitive baseline may not fully return. The exam answer for "what's the prognosis" in elderly post-delirium is increased mortality and persistent cognitive impairment, not "full recovery within days."

Short-term in-hospital complications:

Length of stay and cost:

Long-term outcomes (these are heavily tested):

Family burden: caregiver PTSD and depression — particularly after witnessing ICU delirium with hallucinations and agitation.

When to Escalate — ICU, Consults, and Triage

— Airway compromise (severe agitation requiring deep sedation, aspiration, hypoxia, hypoventilation).

— Hemodynamic instability suggesting sepsis, GI bleed, MI, PE driving delirium.

— Status epilepticus including NCSE.

— Severe withdrawal (DTs with CIWA >20 despite escalating benzodiazepines, requiring continuous infusion → ICU).

— Suspected NMS, serotonin syndrome, malignant hyperthermia, anticholinergic toxicity needing physostigmine, lithium/salicylate/TCA overdose.

— New focal neurologic deficit, depressed GCS, signs of herniation → ICU + neurosurgery.

— Refractory agitation despite optimized non-pharmacologic + first-line pharmacotherapy.

— Geriatrics: any elderly patient with delirium, especially with polypharmacy or recurrent episodes; consider geriatric co-management for hip fracture/post-op.

— Neurology: focal deficits, seizures, suspected encephalitis, unexplained persistent altered mental status, abnormal EEG.

— Psychiatry: distinguishing delirium from primary psychiatric illness (depression with psychotic features, mania, postpartum psychosis), suicidality, or pre-existing severe mental illness complicating management; capacity assessment.

— Palliative care: terminal delirium, complex goals-of-care, family distress.

— Toxicology/poison control: any suspected overdose or unfamiliar toxidrome.

— Addiction medicine: alcohol/opioid withdrawal management plus discharge MAT planning.

— At admission and at any clinical deterioration; surrogate identification if patient lacks capacity.

— Resolution of underlying precipitant, off vasopressors, hemodynamically stable, no continuous antipsychotic infusion, CAM-negative or stable agitation.

CCS pearl: In a CCS case, place a sitter and call psychiatry for capacity assessment before a delirious patient signs out AMA or refuses a critical procedure. Documenting capacity is the testable, scoreable move — not arguing with the patient.

Transfer to higher level of care when:

Consults — who and when:

Code status and goals-of-care reassessment:

Step-down/floor de-escalation criteria:

Key Differentials — Same-Category (Acute Cognitive/Behavioral) Causes

— Chronic, gradual, progressive cognitive decline over months–years; attention preserved early, level of consciousness normal.

— Stem clue: family says "she's been getting more forgetful over the past year" — that's dementia. "She was fine 3 days ago" — that's delirium.

— Lewy body dementia can mimic delirium: fluctuating cognition, visual hallucinations, parkinsonism, REM sleep behavior disorder — but pattern is chronic with fluctuation, not acute onset; severe neuroleptic sensitivity is a hallmark.

— Can present with poor attention, psychomotor slowing, withdrawal mimicking hypoactive delirium.

— Onset weeks to months; preserved orientation; patient often gives "I don't know" answers; diurnal mood variation (worse mornings); previous depressive episodes.

— Treatment: SSRIs; cognitive deficits often improve.

— Onset in adolescence/young adulthood; auditory > visual hallucinations; clear consciousness; sustained (not fluctuating) symptoms.

— Stem clue: a 65-year-old with new visual hallucinations is not new schizophrenia — work up delirium or DLB.

— Elevated mood, decreased need for sleep, grandiosity, pressured speech; usually preserved attention initially.

— In elderly with new "mania" — suspect secondary mania from steroids, levodopa, infection, or frontal lobe pathology.

— Term "ICU psychosis" is outdated — the entity is delirium driven by sedation, sleep disruption, immobilization, severe illness; treat as delirium.

— Mutism, immobility, posturing, waxy flexibility, echolalia; can mimic hypoactive delirium.

— Lorazepam challenge (1–2 mg IV/IM) — dramatic improvement supports catatonia; ECT for refractory.

— Important because catatonia and delirium can coexist ("delirious catatonia").

Key distinction: Attention is the single best bedside discriminator. Delirium = inattentive; dementia, depression, primary psychosis = generally attentive (at least early). Always test attention (months backward, digit span) before committing to a diagnosis.

Dementia:

Depression (especially in elderly — "pseudodementia"):

Primary psychotic disorders (schizophrenia, schizoaffective):

Mania / bipolar with psychosis:

Acute stress reaction / ICU psychosis (now reframed as ICU delirium):

Catatonia:

Key Differentials — Other-Category (Medical/Neurologic) Causes

— Triad: encephalopathy + ophthalmoplegia (lateral rectus palsy, nystagmus) + ataxia — full triad in <20%; suspect in any alcohol use, hyperemesis, bariatric surgery, malnutrition.

— Treat empirically: thiamine 500 mg IV TID × 2–3 days, then taper — before glucose to avoid precipitating Wernicke.

— Persistent altered mental status without obvious motor seizures; subtle eye deviation, twitching, automatisms. EEG diagnosis.

— Right MCA (neglect, confusion, often missed without focal weakness), thalamic/bilateral PCA, caudate strokes can present as acute confusion without classic hemiparesis.

— Always image if new focal deficit or unexplained acute change.

— Fever + headache + neck stiffness + altered mental status; HSV encephalitis — temporal lobe involvement, seizures, personality change.

— Severely elevated BP with encephalopathy, seizures, visual changes; MRI shows posterior white matter edema; treat by gradual BP reduction.

— Hyponatremia, hypercalcemia (malignancy, hyperparathyroidism), hypo-/hyperglycemia, hepatic, uremic, thyroid storm/myxedema, adrenal crisis, hypoxia, hypercapnia, CO poisoning.

— Serotonin syndrome (clonus, hyperreflexia, autonomic instability) vs NMS (rigidity, hyperthermia, after antipsychotic) vs anticholinergic toxidrome vs opioid intoxication.

— Thyroid storm (tachycardia, hyperthermia, agitation), myxedema coma (hypothermia, bradycardia, hypoventilation, hyponatremia), adrenal insufficiency (hypotension, hyponatremia, hyperkalemia).

— Anti-NMDA receptor (young women, ovarian teratoma, psychiatric prodrome, movement disorder, seizures), LGI1, GAD65.

Board pearl: "Confused alcoholic" → give thiamine BEFORE dextrose, always. Giving glucose alone to a thiamine-deficient patient can precipitate Wernicke encephalopathy — a classic Step 3 trap.

Wernicke encephalopathy:

Nonconvulsive status epilepticus (NCSE):

Stroke:

Meningitis/encephalitis:

Hypertensive emergency / PRES:

Toxic-metabolic:

Medication toxicity / withdrawal:

Endocrine:

Autoimmune/paraneoplastic encephalitis:

Secondary Prevention and Discharge Planning

— Discontinue antipsychotics started for in-hospital delirium unless there is a clear ongoing indication; never reflexively continue at home.

— Continue deprescribing of Beers/STOPP-flagged medications: anticholinergics, benzodiazepines, Z-drugs, meperidine, sliding-scale insulin only regimens.

— Provide written medication list with discontinued drugs explicitly noted, reasons, and instructions to PCP/SNF.

— Pharmacist medication review prior to discharge is a quality measure.

— Up to 40% of patients have residual cognitive or functional deficits at discharge; counsel patient and family that recovery is gradual (weeks–months) and not always complete.

— Sleep: nonpharmacologic sleep hygiene; if pharmacologic needed, melatonin preferred over diphenhydramine or Z-drugs.

— Pain: scheduled acetaminophen + targeted opioid-sparing regimens.

— Provide patient/family with a "delirium passport": documents this episode, precipitants, drugs to avoid, early warning signs (acute change, fluctuating attention, sleep reversal) — to share at future hospitalizations.

— Encourage early activation of HELP-like measures at any rehospitalization.

— Influenza, pneumococcal, COVID-19, shingles, Tdap up to date.

— UTI prevention strategies if recurrent; review need for chronic Foley.

— Initiate MAT (naltrexone, acamprosate for AUD; buprenorphine/naltrexone for OUD) before discharge if applicable; connect to outpatient treatment and 12-step or counseling.

— Update advance directive, healthcare proxy, POLST/MOLST especially in elderly with delirium episode — they have measurably higher mortality over the next year.

Step 3 management: At discharge, the two interventions with strongest evidence and highest exam yield are (1) stop the antipsychotic started inpatient and (2) provide a reconciled medication list with Beers drugs removed, sent to the PCP and patient.

Medication reconciliation at discharge (highest-yield Step 3 intervention):

Address persistent symptoms:

Recurrence prevention:

Vaccinations and infection prevention (precipitants of recurrence):

Substance use:

Goals-of-care documentation:

Follow-Up, Monitoring, and Rehabilitation

— PCP visit within 7 days of discharge — earlier (48–72 h) if frail, multiple medication changes, or new SNF placement.

— Geriatrics referral for any patient over 75 with first delirium episode or recurrent episodes.

— Cognitive reassessment at 1, 3, and 6 months using MoCA or MMSE — establishes new baseline and detects unmasked dementia.

— Repeat medication review at every follow-up; cumulative anticholinergic burden score (ACB) tracking.

— Home health PT/OT to address deconditioning, ADL/IADL retraining, fall prevention.

— Cardiac/pulmonary rehab when delirium followed an MI/COPD exacerbation/sepsis.

— Cognitive rehabilitation — emerging evidence; structured cognitive training, social engagement.

— Driving assessment if pre-illness driver — formal evaluation before resuming driving; document discussion (mandatory reporting varies by state).

— Up to 25% of ICU delirium survivors develop PTSD from frightening hallucinations and ICU experiences; screen with IES-R or PCL-5.

— Screen for depression (PHQ-9) at 1 and 3 months — common after prolonged hospitalization.

— ICU diary intervention (nurse-/family-kept narrative of hospital course) reduces PTSD.

— Educate on signs of recurrence, medication safety, fall prevention, home environment modifications.

— Caregiver burden assessment; respite care referral if needed.

— Reassess fitness for independent living; consider assisted living or SNF if functional decline persistent.

Board pearl: A delirium episode is an inflection point — about 40% of patients with no prior dementia diagnosis will meet criteria for dementia within 1–3 years. Schedule formal cognitive testing at 3 months rather than dismissing residual deficits as "still recovering."

Post-discharge follow-up cadence:

Functional rehabilitation:

Mental health and PTSD screening:

Family/caregiver support:

Living situation:

Ethical, Legal, and Patient Safety Considerations

— Capacity is decision-specific, time-specific, and fluctuates with delirium — a patient may have capacity for low-stakes decisions (meal choice) but not high-stakes (refusing dialysis).

— Four elements: (1) understand information, (2) appreciate consequences for self, (3) reason through options, (4) communicate a stable choice.

— Document a capacity assessment in the chart for any consent-relevant decision; psychiatry consult when capacity is contested or stakes are high.

— If lacking capacity → identify healthcare surrogate (DPOA, then next of kin per state law); use substituted judgment then best interest.

— A delirious patient cannot validly consent to surgery or DNR change made during the episode — defer non-emergent decisions until delirium clears; for emergent decisions, use surrogate or emergency exception.

— A previously executed advance directive remains valid and should be honored.

— Least restrictive option first: family/sitter, environmental modification, then chemical, then physical.

— Physical restraints require a physician order, time limit (typically ≤24 h for non-violent, 4 h for violent in adults), documented justification, regular reassessment, and CMS-mandated face-to-face evaluation within 1 hour.

— Restraints increase injury risk; document failure of alternatives.

— Elder abuse/neglect — bruises, malnutrition, dehydration, untreated pressure injuries, financial exploitation — mandatory reporting to Adult Protective Services in all states; physicians are mandated reporters.

— Suspected non-accidental drug administration → report.

— Discharge with active delirium is a sentinel safety event — verify resolution or, if discharging to SNF, ensure receiving facility has appropriate resources, written sign-out, accurate medication reconciliation, and explicit communication of antipsychotic stop dates.

— Avoid "transfer of an unstable mental status" without warm handoff to the next physician.

Step 3 management: Never accept "patient signed out AMA" at face value in a delirious patient — AMA discharge requires intact capacity. Reassess, involve surrogate, and document; an AMA signature obtained from a delirious patient is not legally valid consent.

Decision-making capacity:

Informed consent edge cases:

Restraints — legal and safety:

Mandatory reporting:

Transitions of care (high Step 3 yield):

High-Yield Associations and Rapid-Fire Facts

Board pearl: When in doubt on a Step 3 stem, the right answer almost always involves removing a tether, stopping a Beers drug, or correcting a metabolic abnormality — not adding a new medication.

Strongest non-modifiable risk factor: age ≥65 and pre-existing dementia (5× risk).

Highest-risk surgery: hip fracture repair and cardiac surgery in elderly.

Drug class most likely to cause inpatient delirium: benzodiazepines (especially long-acting like diazepam, chlordiazepoxide), followed by anticholinergics (diphenhydramine, oxybutynin, TCAs) and opioids (meperidine worst, then morphine in renal impairment).

Best single ICU sedative for delirium prevention: dexmedetomidine (over propofol, over benzos).

Best non-pharmacologic preventive program: HELP (Hospital Elder Life Program) — reduces incidence ~30–40%.

Best validated bedside screen: CAM (sensitivity 94%, specificity 89%); CAM-ICU for ventilated patients; 4AT in busy ED/floor settings.

EEG in delirium: diffuse background slowing; triphasic waves suggest hepatic/uremic/anoxic encephalopathy.

First-line drug for severe agitation: haloperidol 0.25–0.5 mg in elderly (IV with cardiac monitoring); quetiapine in Parkinson/DLB.

Drugs to absolutely avoid in DLB: typical antipsychotics (haloperidol) → severe neuroleptic sensitivity.

Alcohol withdrawal: benzodiazepines (lorazepam, diazepam) first-line; CIWA-Ar for titration; thiamine before glucose.

Opioid choice in renal failure: hydromorphone or fentanyl (avoid morphine, meperidine).

Sleep aid of choice in hospitalized elderly: melatonin or ramelteon (avoid diphenhydramine, Z-drugs, benzodiazepines).

Mortality: ~35–40% at 1 year after delirium episode in elderly; 2× independent risk.

Asymptomatic bacteriuria: do not treat — does not improve delirium and risks C. difficile.

Wernicke triad: encephalopathy + ophthalmoplegia + ataxia; thiamine empirically.

Most missed subtype: hypoactive — worst prognosis.

HSV encephalitis: temporal lobe, fever, seizures — empiric acyclovir while awaiting PCR.

Postpartum psychosis: psychiatric emergency, admit, antipsychotic + mood stabilizer.

Board Question Stem Patterns

— 82-year-old POD#2 from hip ORIF, sleeping all day, eats little, doesn't engage. Family says "she's not herself." Vitals normal.

— Trap: "reassure family, observe." Correct: screen with CAM — likely hypoactive delirium; review medications (diphenhydramine on order set?), bladder scan, electrolytes.

— 55-year-old admitted for pancreatitis, hospital day 3, becomes tremulous, tachycardic, hypertensive, sees bugs on the wall.

— Correct: lorazepam by CIWA protocol + thiamine + IV fluids; ICU if CIWA >20 or autonomic instability.

— 78-year-old with new confusion; UA shows bacteria, leukocyte esterase, but patient denies dysuria; afebrile.

— Trap: "start ceftriaxone for UTI." Correct: look for true cause — medication review, electrolytes, bladder scan, exam — asymptomatic bacteriuria does not cause delirium.

— Elderly woman post-cholecystectomy on scopolamine patch + diphenhydramine for sleep + oxybutynin for OAB, becomes febrile, dry, mydriatic, agitated.

— Correct: remove offending drugs (anticholinergic toxidrome); supportive care; physostigmine only if severe.

— Delirious patient demands to leave AMA.

— Correct: assess capacity; if absent, involve surrogate, do not allow AMA discharge.

— PD patient hospitalized, hallucinating, agitated.

— Trap: haloperidol. Correct: quetiapine (low D2 affinity); review dopamine agonists and anticholinergics.

— Mechanically ventilated patient with delirium on midazolam drip.

— Correct: switch to dexmedetomidine, daily SAT/SBT, mobilize.

— Elderly post-delirium being discharged still on haloperidol started inpatient.

— Correct: discontinue antipsychotic at discharge; document reason, communicate to PCP.

Key distinction: Step 3 stems reward the management step that prevents the next harm — deprescribe, reassess capacity, prevent recurrence — over the diagnostic step. Always ask: "what does this patient need next to be safer?"

Pattern 1 — "The quiet elderly patient":

Pattern 2 — "The agitated alcoholic":

Pattern 3 — "The UTI red herring":

Pattern 4 — "The post-op anticholinergic":

Pattern 5 — "Capacity question":

Pattern 6 — "Parkinson + hallucinations":

Pattern 7 — "The ICU sedation choice":

Pattern 8 — "Discharge medication reconciliation":

One-Line Recap

Delirium is an acute, fluctuating disturbance of attention caused by an identifiable medical precipitant — the cure is finding and reversing that cause, not sedating the patient.

Board pearl: The single most testable, most clinically impactful action in delirium is deprescribing — pull the offending Beers/anticholinergic/benzodiazepine/Z-drug/meperidine before adding anything new, and document a capacity assessment before honoring any patient refusal of care.

Diagnosis: CAM-positive (acute onset + fluctuation + inattention + disorganized thinking OR altered consciousness); always test attention, get collateral, and establish a baseline before labeling.

Workup: bedside glucose, vitals (including SpO2 and temperature), bladder scan, full medication review FIRST; then CBC/CMP/Mg/UA/CXR/ECG; reserve head CT for focal deficits, trauma, anticoagulation, or unexplained cases; LP/EEG/MRI only when clinically driven.

Management: treat the underlying cause; deploy the HELP/ABCDEF non-pharmacologic bundle (reorient, glasses/hearing aids, mobilize, sleep hygiene, remove tethers); reserve low-dose haloperidol or quetiapine for safety-threatening agitation; avoid benzodiazepines except in alcohol/benzodiazepine withdrawal or seizures; dexmedetomidine over benzodiazepines for ICU sedation.

Transitions and prognosis: stop the antipsychotic at discharge, reconcile against Beers/STOPP, schedule PCP follow-up within 7 days and cognitive reassessment at 3 months; counsel that 1-year mortality and persistent cognitive decline are substantial — delirium is a sentinel event, not a transient nuisance.