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.

Types of Delirium

Hyperactive delirium: Restlessness, agitation, hallucinations.
Hypoactive delirium: Lethargy, reduced alertness, often missed.
Mixed delirium: Alternating hyperactive and hypoactive features.

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.

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).

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).

Differential Diagnosis

Dementia: Chronic, progressive cognitive decline (delirium is acute, fluctuating).
Depression (pseudodementia).
Psychosis (schizophrenia, mania).
Seizures (postictal state).

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.

Management and Treatment

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

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).

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.

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.

Complications

Increased hospital stay and costs.
Functional decline and immobility.
Falls, aspiration pneumonia, pressure ulcers.
Long-term cognitive impairment or dementia.
Higher mortality.

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%.

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.

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