DELIRIUM

Acute brain dysfunction with inattention, fluctuating course, and disorganized thinking or altered LOC — highly prevalent and underdiagnosed in hospitalized patients

SYMPTOMS / ASSOCIATED SX

• Acute onset (hours to days); fluctuating course — hallmark feature

• Inattention: cannot follow commands, serial 7s, digit span; easily distracted

• Disorganized thinking: rambling speech, illogical flow, tangentiality

• Hyperactive: agitation, pulling lines (most recognized but less common ~25%)

• Hypoactive: quiet, withdrawn, sleeping — more common (~50%), frequently missed, WORSE prognosis

• Sleep-wake cycle disruption; visual hallucinations; sundowning

DENIES

• Gradual onset over weeks/months (dementia — delirium can be superimposed on dementia)

• Sustained normal attention periods (distinguishes from dementia)

• Focal deficits/meningismus (structural/infectious cause needing separate workup)

SOCIAL HISTORY

• Baseline cognitive function (prior dementia, prior MMSE); sensory impairments (hearing aids, glasses)

• Alcohol or benzodiazepine use history (withdrawal delirium); social support

MAIN ETIOLOGY

• Predisposing (vulnerability): age ≥70, pre-existing cognitive impairment, sensory impairment, dehydration, functional dependence

• Precipitating (acute insults): infection/sepsis (most common), medications (Beers Criteria agents), pain, urinary retention, constipation, immobility, sleep deprivation, surgery

• Highest-risk drugs: benzodiazepines, opioids, anticholinergics, steroids, H2 blockers, antihistamines

MOST COMMON DDX

• Dementia (chronic, gradual, preserved attention early — delirium is ACUTE and FLUCTUATING)

• Depression (flat affect, psychomotor slowing, alert and oriented; PHQ-9)

• Nonconvulsive status epilepticus (EEG; subtle motor signs)

• Alcohol/benzo withdrawal (tremors, autonomic instability, tachycardia — CIWA-Ar)

• Urinary retention/fecal impaction (bladder scan, rectal exam — common precipitants)

• Wernicke's encephalopathy (alcohol history, ophthalmoplegia)

DATA

• CAM (Confusion Assessment Method): (+) if (1) acute + fluctuating AND (2) inattention AND (3) disorganized thinking OR altered LOC — sensitivity 94–100%

• BMP, CBC, LFTs, ammonia, TSH, B12; UA + culture; CXR; blood cultures if infection suspected

• Urine/serum tox screen; CIWA-Ar score if alcohol/benzo withdrawal

• Bladder ultrasound (urinary retention — 400–500 mL threshold for delirium contribution)

• CT head if new focal deficit or no other explanation; EEG if NCSE suspected

• Medication reconciliation — all agents with CNS effects

HOME MEDS

• Benzodiazepines — hold (worsen delirium); exception: withdrawal (CIWA-Ar protocol)

• Anticholinergics (oxybutynin, diphenhydramine, TCAs, promethazine) — discontinue immediately

• H2 blockers (famotidine) — switch to PPI if acid suppression needed

• Hypnotics (zolpidem, eszopiclone) — hold; use non-pharmacologic sleep aids

PLAN

• Non-pharmacologic (ACE order set) Applied

  • Reorientation: clocks, calendars, familiar objects; staff introduce themselves

  • Sleep hygiene: lights off at night, minimize nighttime vitals/labs, cluster care

  • Sensory aids: ensure hearing aids and glasses in use

  • Early mobilization: PT/OT daily — out of bed with assistance

  • Avoid Foley catheters, physical restraints, unnecessary IVs

  • Adequate hydration and nutrition; adequate pain control

• Pharmacologic (ONLY for safety — severe agitation; NOT first-line):

  • Haloperidol 0.5–1 mg PO/IV q4–6h PRN (max 3–5 mg/day elderly; monitor QTc)

  • Quetiapine 12.5–25 mg PO BID/TID (preferred if Parkinson's or DLB)

  • NEVER use benzodiazepines for delirium (except alcohol/benzo withdrawal)

  • Avoid ALL antipsychotics in DLB — only quetiapine or clozapine acceptable

• Alcohol withdrawal: CIWA-Ar ≥8 → lorazepam 1–2 mg IV/PO q1h PRN; thiamine 100 mg IV/IM daily ×3 days

• DISCHARGE:

  • Do not discharge until delirium resolved or returned to baseline

  • Document offending medications as contraindications

  • Family education: delirium may take days–weeks to fully resolve

  • MoCA/MMSE at 4–6 weeks follow-up to re-baseline cognition

RED FLAGS

• CIWA-Ar ≥15 or alcohol withdrawal seizure → ICU; IV benzodiazepine loading; consider phenobarbital

• DLB (visual hallucinations + fluctuating + Parkinsonism) → NO antipsychotics except quetiapine/clozapine — NMS risk

• NMS: fever + rigidity + AMS + autonomic instability after antipsychotic → stop drug; dantrolene 1–2.5 mg/kg IV; bromocriptine; ICU

• Unexplained persistent delirium → EEG, MRI brain, LP (autoimmune encephalitis)

SENIOR IM RESIDENT PEARLS

• CAM requires: (1) acute + fluctuating PLUS (2) inattention PLUS (3) disorganized thinking OR (4) altered LOC

• Hypoactive delirium (>50%) has worse prognosis — do not miss the quiet, drowsy patient

• HELP Program (Inouye et al.): non-pharmacologic intervention reduced delirium incidence by 33% and delirium days by 40%

• Haloperidol does NOT prevent or treat delirium (HOPE-ICU trial) — non-pharm is superior for prevention

• Common mistake: using diphenhydramine (Benadryl) for sleep in elderly — highly anticholinergic; worsens delirium

• Common mistake: attributing delirium to dementia — dementia is the greatest RISK FACTOR for delirium; always search for acute precipitant

• ABCDEF ICU bundle reduces ICU delirium and ventilator days; target RASS –1 to 0