Delirium

Introduction

Delirium is an acute, fluctuating disturbance of consciousness, attention, and cognition. It typically develops over hours to days and is a medical emergency. It is common in elderly, hospitalized, or critically ill patients, with prevalence rates up to 50% in intensive care units.

Delirium is important because:

• It is associated with increased hospital stay, complications, mortality, and long-term cognitive decline.

• It is often preventable and reversible if the underlying cause is treated early.

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Types of Delirium

1. Hyperactive delirium: Restlessness, agitation, hallucinations.

2. Hypoactive delirium: Lethargy, reduced alertness, often missed.

3. Mixed delirium: Alternating hyperactive and hypoactive features.

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Pathophysiology

• Neurotransmitter imbalance:

  • ↓ Acetylcholine (critical for attention, memory).

  • ↑ Dopamine (causes hallucinations, agitation).

• Neuroinflammation: Cytokine release in infection, surgery, trauma.

• Metabolic dysfunction: Hypoxia, hypoglycemia, electrolyte imbalance.

• Stress and sleep-wake cycle disturbance.

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Causes and Risk Factors

1. Medical Illnesses

• Infections: pneumonia, urinary tract infection, sepsis, meningitis.

• Metabolic/electrolyte disorders: hyponatremia, hypercalcemia, hypoglycemia, hepatic/renal failure.

• Hypoxia (respiratory failure, cardiac arrest).

• Stroke, head trauma, seizures, intracranial hemorrhage.

2. Drugs and Toxins

• Anticholinergics (atropine, oxybutynin).

• Benzodiazepines, opioids.

• Corticosteroids, digoxin.

• Alcohol or drug intoxication.

• Drug withdrawal (alcohol, benzodiazepines).

3. Surgery and Hospitalization

• Postoperative delirium (especially after cardiac and orthopedic surgery).

• ICU delirium.

4. Risk Factors

• Elderly age.

• Dementia or cognitive impairment.

• Multiple comorbidities.

• Polypharmacy.

• Sensory impairment (hearing/vision).

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Clinical Features

Core Features

• Disturbance of attention and awareness (easily distracted, reduced orientation).

• Acute onset and fluctuating course.

• Additional cognitive disturbance: memory, language, perception.

Associated Features

• Sleep–wake cycle disruption (day-night reversal).

• Perceptual disturbances (hallucinations, illusions).

• Emotional changes (fear, paranoia, irritability).

• Motor symptoms: agitation, restlessness (hyperactive); reduced activity (hypoactive).

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Differential Diagnosis

• Dementia: Chronic, progressive cognitive decline (delirium is acute, fluctuating).

• Depression (pseudodementia).

• Psychosis (schizophrenia, mania).

• Seizures (postictal state).

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Diagnostic Approach

1. Clinical Tools

• Confusion Assessment Method (CAM):

  • Acute onset + fluctuating course

  • Inattention

  • Disorganized thinking

  • Altered consciousness
    (Diagnosis = 1 + 2 + either 3 or 4).

• 4AT (rapid delirium screening): Alertness, AMT4 (cognition), attention test, acute change.

2. History and Examination

• Collateral history from family/caregivers.

• Medication review.

• Full physical and neurological exam.

3. Investigations

• Blood tests: CBC, electrolytes, renal/liver function, glucose, calcium, thyroid.

• Infection screen: Chest X-ray, urinalysis/culture, blood cultures.

• ECG: Arrhythmias, QT prolongation (drug-induced).

• Neuroimaging (CT/MRI): If stroke, head trauma, hemorrhage suspected.

• Lumbar puncture: If meningitis/encephalitis suspected.

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Management and Treatment

Principle: Delirium is a medical emergency — treat underlying cause + provide supportive care.

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A. Identify and Treat Underlying Cause

• Stop offending drugs (anticholinergics, sedatives, opioids if possible).

• Treat infection (antibiotics based on source):

  • Ceftriaxone 1–2 g IV once daily (for pneumonia/UTI, adjust per culture).

• Correct metabolic derangements:

  • Hyponatremia: slow sodium correction with IV saline.

  • Hypoglycemia: IV dextrose 25–50 g bolus.

  • Hypoxia: Supplemental oxygen.

• Manage alcohol/benzo withdrawal:

  • Diazepam 10 mg orally/IV every 6–8 h (tapering schedule).

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B. Supportive Care

• Calm, well-lit environment.

• Reorientation: clocks, calendars, familiar objects.

• Ensure hearing aids/glasses are used.

• Encourage mobilization.

• Adequate hydration, nutrition, sleep hygiene.

• Involve family for reassurance.

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C. Symptomatic Pharmacological Management

(Only if patient is severely agitated, at risk of harming self/others, or non-responsive to non-drug measures).

• Haloperidol (first-line):

  • 0.5–1 mg orally/IM every 8 h as needed (max 5 mg/day).

  • Avoid in Parkinson’s disease or Lewy body dementia.

• Olanzapine: 2.5–5 mg orally once daily (alternative to haloperidol).

• Quetiapine: 12.5–25 mg orally once or twice daily (preferred in Parkinson’s).

• Benzodiazepines: Only for alcohol/benzodiazepine withdrawal delirium.

  • Lorazepam 1–2 mg orally/IM/IV every 4–6 h as needed.

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Complications

• Increased hospital stay and costs.

• Functional decline and immobility.

• Falls, aspiration pneumonia, pressure ulcers.

• Long-term cognitive impairment or dementia.

• Higher mortality.

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Prognosis

• Acute delirium: Usually reversible if underlying cause treated.

• Elderly and critically ill patients: Higher risk of persistent cognitive decline.

• Mortality in hospitalized patients: 10–30%.

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Patient and Family Education

• Delirium is often temporary and treatable, but it signals serious illness.

• Family involvement helps in reorientation and reassurance.

• Prevention:

• Adequate hydration and nutrition.

• Avoid unnecessary sedatives and anticholinergic drugs.

• Ensure mobility, eyeglasses, hearing aids.

• Early recognition of infections and metabolic issues.