Delirium

complete reference · CAM · DELIRIUM mnemonic · non-pharm bundle · antipsychotic only for danger · Full Card

Symptoms / Associated Sx

• An acute (hours-days), fluctuating disturbance of attention and awareness with disorganized thinking — the hallmark is inattention (can't sustain or shift focus; fails serial 7s, days-of-week-backward, digit span). Consciousness may be hyperalert or depressed. CAM (Confusion Assessment Method): (1) acute onset + fluctuating course AND (2) inattention, PLUS either (3) disorganized thinking OR (4) altered level of consciousness.

• Hyperactive (agitated, hallucinating — easily noticed), hypoactive (quiet, withdrawn, lethargic — frequently missed and carries a worse prognosis), or mixed. Sleep-wake reversal and perceptual disturbances are common.

Neg

• Pt denies/​lacks a chronic, stable, slowly-progressive cognitive decline without an acute change — argues against dementia alone (dementia is the biggest risk factor for delirium, and the two coexist; the acute fluctuation and inattention point to superimposed delirium)

• Attention is impaired (not preserved) — argues against primary depression or a psychiatric disorder (hypoactive delirium mimics depression, but attention is intact in depression; a clear sensorium with intact attention favors psychiatric illness)

• No focal neurologic deficit or aphasia — argues against acute stroke as the explanation (though a strategic stroke can cause confusion; image if focal)

• Returns to a recognizable baseline as the cause is treated — supports delirium over a fixed structural process.

Social History (SHx)

• Baseline cognitive status from collateral (family/facility) is essential — you cannot diagnose an acute change without knowing the baseline.

• Alcohol and benzodiazepine use (withdrawal); polypharmacy and recent medication changes; prior episodes of delirium; sensory impairments (vision/hearing); functional baseline.

Main Etiology

• Almost always multifactorial. Mnemonic "DELIRIUM": Drugs (anticholinergics, opioids, benzodiazepines, sedative-hypnotics, steroids), Electrolytes/endocrine (Na, Ca, glucose, thyroid), Lack of drugs (alcohol/benzo withdrawal, uncontrolled pain), Infection (UTI, pneumonia, sepsis, often occult in elders), Reduced sensory input / urinary or stool Retention, Intracranial (stroke, hemorrhage, non-convulsive seizures, meningitis), Uremia and other metabolic (hypoxia, hypercapnia, hepatic), Myocardial/pulmonary (MI, PE), post-operative state, and environmental factors.

RF

• Modifiable (precipitating): deliriogenic medications, physical restraints and tethers (Foley catheters, IV lines, telemetry), sleep deprivation, sensory deprivation, untreated pain, dehydration, immobility.

• Non-modifiable (predisposing): advanced age, baseline dementia/cognitive impairment, frailty, multiple comorbidities, sensory impairment, prior delirium.

Data

• CBC, CMP (electrolytes, BUN/Cr, glucose, LFTs), calcium, magnesium, phosphate (metabolic causes — high yield)

• Urinalysis + culture, chest X-ray, blood cultures if febrile (occult infection — the classic precipitant in elders)

• Medication reconciliation (the single most common reversible cause — review every new/PRN drug)

• Pulse oximetry/ABG, TSH, B12 (hypoxia/hypercapnia, thyroid, deficiency); ECG and troponin if cardiac suspicion

• Non-contrast head CT if focal deficit, head trauma, anticoagulation, depressed consciousness, or no cause found on initial workup (stroke, subdural, mass)

• EEG if non-convulsive status epilepticus is suspected (not waking, subtle twitching); LP if fever + meningismus or unexplained (CNS infection)

DDx

Dementia (chronic, slowly progressive, attention relatively preserved early — but predisposes to delirium) · depression (hypoactive mimic; attention intact, mood-congruent) · primary psychosis (clear sensorium, intact orientation/attention) · non-convulsive status epilepticus (fluctuating consciousness, EEG diagnostic) · Wernicke encephalopathy (ophthalmoplegia, ataxia, confusion in malnutrition/alcohol) · acute stroke (focal deficits)

Home Meds

• Stop or minimize deliriogenic drugs — anticholinergics (diphenhydramine, oxybutynin, scopolamine), benzodiazepines, sedative-hypnotics (zolpidem), opioids where feasible, H2 blockers, muscle relaxants.

• Do not abruptly withdraw chronic benzodiazepines or alcohol (precipitates withdrawal delirium) — taper or treat withdrawal appropriately.

• Continue essential home meds; substitute safer alternatives for high-risk agents.

Plan

Consults

• Neurology — focal signs, suspected seizure/NCSE, or diagnostic uncertainty.

• Psychiatry — severe or refractory behavioral disturbance, medication guidance.

• Geriatrics — older adults, polypharmacy, deprescribing.

• PT / OT — early mobilization, functional assessment, falls prevention.

Find and treat the cause

• The workup is the treatment. Systematically address each contributor: treat infection (antibiotics), correct electrolytes/glucose, restore oxygenation, relieve urinary/stool retention, control pain (acetaminophen first; minimize opioids), and remove offending drugs.

Non-pharmacologic bundle (first-line, evidence-based)

• Reorientation (clocks, calendars, familiar objects), restore glasses and hearing aids, day-night lighting and a sleep-promotion protocol (cluster care, minimize nighttime vitals/labs), early mobilization, remove tethers (discontinue Foley, IV lines, telemetry, and restraints as soon as possible), encourage family presence, ensure hydration and nutrition, regular bowel/bladder routines. (HELP/ABCDEF-type bundles reduce delirium incidence and duration.)

Pharmacologic — only for dangerous agitation

• Reserve antipsychotics for agitation that threatens patient or staff safety or essential care and cannot be redirected — they do not treat delirium or shorten it. Use the lowest effective dose for the shortest time: haloperidol (Haldol) 0.25–0.5 mg PO/IV/IM (monitor QTc, extrapyramidal effects) or quetiapine (Seroquel) 12.5–25 mg PO (preferred in Parkinson's/Lewy body). Avoid benzodiazepines — they worsen and prolong delirium — except when the cause is alcohol or benzodiazepine withdrawal (then they are the treatment).

Always

• PT / OT eval and treat — mobilize early, prevent deconditioning and falls.

• Trend: daily CAM/attention testing, sleep-wake pattern, medication list, and resolution of the underlying cause; document baseline vs current cognition.

• Escalation triggers: hypoxia/airway compromise → ICU · hemodynamic instability from the precipitant (sepsis, MI, GI bleed) → ICU · non-convulsive status on EEG → ICU/neurology · agitation uncontrollable and unsafe despite measures → higher level of monitoring.

• Discharge checklist: deprescribed list with deliriogenic drugs removed/flagged · documented baseline cognition and that delirium is resolving (full resolution can take weeks, especially with dementia) · primary care/geriatrics follow-up for persistent cognitive change · family education on delirium and recurrence risk · sensory aids ensured · return precautions (recurrent acute confusion, fever, focal signs).

Red Flags — Don't Miss

• Hypoactive delirium — the quiet, "pleasantly confused" patient is easily missed and does worse; screen with CAM, don't reassure.
• Occult infection / sepsis in an elder presenting only as confusion → full septic workup.
• Non-convulsive status epilepticus masquerading as delirium → EEG if not waking up.
• Wernicke encephalopathy (alcohol/malnutrition) → give thiamine empirically before glucose.
• Structural cause (subdural, stroke) — focal signs, anticoagulation, trauma → CT.
• Withdrawal (alcohol/benzo) — do not "treat" with antipsychotics; give benzodiazepines.

Senior IM Resident Pearls

• Delirium is a symptom, not a diagnosis. The entire job is finding and reversing the cause(s) — it's almost always several at once. "Sundowning" is not an explanation; it's a prompt to look.
• Inattention is the core feature. Test it at the bedside (months backward, serial 7s, digit span). If attention is intact, reconsider depression or psychosis.
• Get the baseline from collateral. Without knowing the prior cognition you can't separate delirium from dementia — and you'll under- or over-call it.
• Non-pharmacologic measures are first-line and actually work. Reorientation, sensory aids, sleep, mobility, and removing tethers reduce incidence and duration; medications do not.
• Antipsychotics are for safety, not for delirium. They don't shorten it or improve outcomes — reserve low-dose haloperidol/quetiapine for dangerous agitation, shortest course possible, watch the QTc.
• Benzodiazepines worsen delirium — the one exception is alcohol/benzodiazepine withdrawal, where they are the treatment.
• The Foley and the lines are part of the problem. Tethers, restraints, and disrupted sleep are modifiable precipitants — pull them as soon as you safely can.
• Common mistake: sedating the hyperactive patient and declaring victory while missing the hypoactive patient entirely — and missing the sepsis, retention, or NCSE underneath.