Delirium

Delirium, also known as acute confusional state, is an acute neuropsychiatric syndrome characterized by disturbance in attention, awareness, and cognition, accompanied by fluctuating levels of consciousness.

Patients typically present with disorientation to time, place, and sometimes person, altered perception, behavioural disturbance, and psychotic symptoms such as hallucinations or paranoia. The condition develops over a short period (hours to days) and tends to fluctuate during the course of the day.

Delirium is usually secondary to an underlying medical or neurological disorder and frequently represents a medical emergency. Misdiagnosis as primary psychiatric illness or acute psychosis must be avoided.

Epidemiology

• Occurs in:

  • 10–30% of hospitalized patients

  • Up to 50% of elderly inpatients

  • High prevalence in ICU settings

• Associated with increased morbidity, mortality, and prolonged hospitalization

Risk Factors

Patient-Related Factors

• Advanced age (>65 years)

• Dementia or cognitive impairment

• Previous delirium episodes

• Severe medical illness

• Sensory impairment (visual/hearing loss)

• Malnutrition or dehydration

Medical Causes

• Infection (UTI, pneumonia, sepsis)

• Metabolic disturbances

• Hypoxia

• Organ failure

• Stroke or head injury

Drug-Related Factors

• Polypharmacy

• Sedatives and hypnotics

• Anticholinergic drugs

• Opioids

• Alcohol or substance withdrawal

Environmental Factors

• Sleep deprivation

• ICU admission

• Immobilization

• Social isolation

Pathophysiology

Delirium results from acute cerebral dysfunction, involving:

• Neurotransmitter imbalance:

  • ↓ Acetylcholine

  • ↑ Dopamine

• Neuroinflammation

• Oxidative stress

• Impaired cerebral metabolism

• Disturbed sleep–wake cycle regulation

Clinical Subtypes

1. Hyperactive Delirium

   • Agitation

   • Restlessness

   • Hallucinations

2. Hypoactive Delirium

   • Lethargy

   • Reduced responsiveness

   • Often missed clinically

3. Mixed Type

   • Fluctuation between hyperactive and hypoactive states

Signs and Symptoms

Cognitive Features

• Reduced attention

• Disorientation

• Memory impairment

• Confusion

• Language disturbance

Behavioural Symptoms

• Agitation

• Aggression

• Restlessness

• Sleep–wake cycle disturbance

Psychotic Features

• Visual hallucinations

• Paranoia

• Delusions

Neurological Features

• Altered level of consciousness

• Fluctuating mental status

Diagnostic Criteria

Diagnosis is clinical.

Key features include:

• Altered level of consciousness

• Disorientation

• Acute onset with fluctuating course

• Agitation or behavioural disturbance

• Hallucinations

• Paranoia

• Evidence of underlying medical cause

Always exclude primary psychiatric disorders before diagnosing delirium.

Differential Diagnosis

• Dementia

• Acute psychotic disorder

• Schizophrenia

• Major depressive disorder with psychosis

• Substance intoxication or withdrawal

• Non-convulsive status epilepticus

Investigations

Initial Assessment (Urgent)

• Full physical examination

• Neurological examination

• Medication review

Laboratory Investigations

• Full blood count

• Electrolytes

• Blood glucose

• Renal function tests

• Liver function tests

• Thyroid function tests

• Infection screening

• Blood cultures where indicated

• Urinalysis

Additional Tests

• Arterial blood gas

• Toxicology screening

• ECG

• Chest X-ray

• CT/MRI brain (if neurological signs present)

Management

Treatment Principles

1. Identify and treat underlying cause

2. Ensure patient safety

3. Control agitation

4. Prevent complications

Delirium management is primarily medical rather than psychiatric.

Non-Pharmacological Management

First-line intervention in all patients:

• Control acute disturbance safely

• Provide calm, well-lit environment

• Frequent reorientation

• Presence of family or caregivers

• Maintain hydration and nutrition

• Correct sensory deficits (glasses/hearing aids)

• Promote normal sleep cycle

• Early mobilization

• Avoid physical restraints where possible

A complete physical assessment must be performed to identify and treat the underlying condition.

Pharmacological Management

General Principle

Treat the underlying medical condition whenever present.

Medication is indicated only when:

• Severe agitation

• Risk of harm

• Interference with essential treatment

Acute Pharmacological Management

Antipsychotic (First-Line)

Haloperidol IM 5 mg

• May repeat after 60 minutes if required

• Maximum dose: 10 mg within 24 hours

• Switch to oral route once stabilized

Monitor closely for:

• Acute dystonia

• QT prolongation

• Neuroleptic malignant syndrome

Benzodiazepines (When Indicated)

Diazepam IV 10 mg

OR

Lorazepam IM 1–4 mg

Use mainly in:

• Alcohol withdrawal delirium

• Sedative withdrawal states

Important Safety Notes

• Benzodiazepines may cause respiratory depression

• Reduce dose by half in elderly or frail patients

• Oral route safest → IM → IV highest risk

• Allow 15–30 minutes before repeating IM dose

• Monitor vital signs continuously

• Prefer haloperidol in respiratory insufficiency

Monitoring

• Level of consciousness

• Respiratory status

• Blood pressure and pulse

• Oxygen saturation

• Hydration status

• Behavioural response

• Drug adverse effects

Complications

• Falls and injury

• Aspiration pneumonia

• Pressure ulcers

• Functional decline

• Long-term cognitive impairment

• Increased mortality

Prevention

Hospital Prevention Strategies

• Early identification of high-risk patients

• Avoid unnecessary sedatives

• Adequate hydration

• Pain control

• Sleep preservation

• Infection prevention

• Early mobilization

Multicomponent prevention programs significantly reduce delirium incidence.

Prognosis

Outcome depends on:

• Speed of cause identification

• Severity of underlying illness

• Patient age and cognitive reserve

Delirium may resolve completely but can lead to persistent cognitive decline, especially in elderly patients.

Patient and Caregiver Education

• Delirium is usually reversible

• Caused by medical illness, not mental weakness

• Early treatment improves recovery

• Recurrence risk exists in vulnerable patients

• Follow-up assessment is essential