Delirium

Overview

Delirium is a serious disturbance in mental abilities that results in confused thinking and reduced awareness of the environment. Unlike dementia, which develops gradually over months or years, delirium typically develops rapidly over hours to days and represents a medical emergency requiring immediate attention.

This acute confusional state affects approximately 20-30% of hospitalized patients, with rates as high as 80% in intensive care units. Delirium is particularly common among older adults, critically ill patients, and those undergoing surgery. The condition is characterized by fluctuating symptoms that tend to worsen in the evening and night, a phenomenon known as "sundowning."

Delirium represents a significant departure from a person's baseline mental function and always has an underlying cause. It's not a disease itself but rather a syndrome - a collection of symptoms that indicate dysfunction in the brain's normal processes. The condition can be life-threatening if left untreated, as it often signals serious underlying medical problems. However, with prompt identification and treatment of the underlying cause, most cases of delirium are reversible, though some patients may experience long-term cognitive effects.

Symptoms of Delirium

Delirium symptoms typically develop over hours to days and fluctuate throughout the day. The hallmark features include inattention, disorganized thinking, and altered level of consciousness. Symptoms often worsen at night when lighting is poor and surroundings are less familiar.

Core Symptoms

Behavioral and Emotional Symptoms

Motor Symptoms

Types of Delirium

Delirium is classified into three subtypes based on psychomotor activity:

• Hyperactive delirium: Restlessness, agitation, mood swings, hallucinations, uncooperativeness
• Hypoactive delirium: Reduced motor activity, sluggishness, drowsiness, appearing to be in a daze
• Mixed delirium: Alternating between hyperactive and hypoactive states

Causes of Delirium

Delirium always has an underlying cause, often multiple contributing factors. Identifying and treating these causes is essential for resolution of symptoms.

Medical Conditions

Infections

• Urinary tract infections (especially in elderly)
• Pneumonia
• Sepsis
• Meningitis or encephalitis
• COVID-19 and other viral infections

Metabolic Imbalances

• Dehydration
• Electrolyte abnormalities (sodium, calcium, magnesium)
• Hypoglycemia or hyperglycemia
• Thyroid disorders
• Liver or kidney failure
• Acid-base disturbances

Neurological Causes

• Stroke
• Seizures or postictal states
• Head trauma
• Brain tumors or metastases
• Subdural hematoma

Medications and Substances

High-Risk Medications

• Anticholinergics: Diphenhydramine, benztropine
• Sedatives: Benzodiazepines, barbiturates
• Opioids: Morphine, fentanyl, oxycodone
• Corticosteroids: Prednisone, dexamethasone
• Psychiatric medications: Some antidepressants, antipsychotics

Substance-Related

• Alcohol intoxication or withdrawal
• Benzodiazepine or barbiturate withdrawal
• Illicit drug use
• Carbon monoxide poisoning

Environmental and Situational Factors

• Surgery: Especially cardiac, orthopedic, and emergency procedures
• ICU admission: Critical illness, mechanical ventilation
• Sensory impairment: Poor vision or hearing
• Sleep deprivation: Common in hospital settings
• Immobilization: Physical restraints, catheters
• Pain: Inadequately controlled pain

Risk Factors

Certain factors significantly increase the likelihood of developing delirium, particularly in hospitalized patients.

Predisposing Factors

• Advanced age: Risk increases significantly after age 65
• Dementia or cognitive impairment: Strongest predictor of delirium
• Previous delirium episodes: Indicates vulnerability
• Functional impairment: Dependence in activities of daily living
• Sensory impairment: Vision or hearing loss
• Chronic medical conditions: Multiple comorbidities
• Depression: Pre-existing mood disorders
• Alcohol abuse: Current or history of alcohol use disorder

Precipitating Factors

• Acute illness: Severity of illness correlates with risk
• Surgery: Major operations, emergency procedures
• Medications: Polypharmacy (≥5 medications)
• Iatrogenic events: Complications from medical care
• Environmental changes: ICU admission, room changes
• Use of restraints: Physical or chemical restraints
• Bladder catheterization: Indwelling catheters
• Malnutrition: Poor nutritional status

Diagnosis

Diagnosing delirium requires careful clinical assessment, as it's often underrecognized or misdiagnosed as dementia or depression. Early detection is crucial for better outcomes.

Diagnostic Criteria (DSM-5)

1. Disturbance in attention and awareness (reduced orientation to environment)
2. Develops over hours to days, represents change from baseline, and fluctuates
3. Additional cognitive disturbance (memory, disorientation, language, perception)
4. Not better explained by pre-existing dementia
5. Evidence of underlying medical cause, substance, or multiple factors

Screening Tools

Confusion Assessment Method (CAM)

Most widely used tool, requiring presence of:

• Acute onset and fluctuating course
• Inattention
• Plus either: Disorganized thinking OR altered consciousness

Other Assessment Tools

• CAM-ICU: For intubated or non-verbal patients
• 4AT: Rapid screening tool
• Delirium Rating Scale: For severity assessment
• ICDSC: ICU screening checklist

Diagnostic Workup

Laboratory Tests

• Complete blood count
• Comprehensive metabolic panel
• Liver function tests
• Thyroid function tests
• Urinalysis and culture
• Blood cultures if fever present
• Arterial blood gas if hypoxia suspected
• Drug levels (digoxin, lithium, etc.)
• Toxicology screen

Imaging Studies

• Chest X-ray: Rule out pneumonia
• Head CT: If focal neurological signs or head trauma
• MRI brain: For suspected stroke or encephalitis
• EEG: If seizures suspected

Other Assessments

• Medication review
• Pain assessment
• Bladder scan for retention
• Lumbar puncture if meningitis suspected

Treatment Options

Treatment of delirium focuses on identifying and addressing underlying causes while providing supportive care to ensure patient safety and comfort.

Address Underlying Causes

The most important intervention is treating the precipitating factors:

• Treat infections: Appropriate antibiotics
• Correct metabolic abnormalities: Hydration, electrolyte replacement
• Optimize medications: Discontinue or reduce deliriogenic drugs
• Manage pain: Adequate analgesia
• Address hypoxia: Oxygen supplementation
• Treat withdrawal: Appropriate protocols for alcohol or benzodiazepine withdrawal

Non-Pharmacological Interventions

Environmental Modifications

• Provide orientation cues (clock, calendar, familiar objects)
• Ensure adequate lighting during day, dim at night
• Minimize noise and disruptions
• Maintain consistent caregivers
• Encourage family presence

Supportive Care

• Mobility: Early mobilization, avoid restraints
• Sleep hygiene: Promote natural sleep-wake cycle
• Sensory aids: Glasses, hearing aids
• Hydration and nutrition: Assist with meals
• Bowel/bladder: Regular toileting, avoid catheters when possible

Pharmacological Management

Medications are reserved for severe agitation posing safety risks:

Antipsychotics

• Haloperidol: 0.5-1 mg PO/IM, traditional first-line
• Quetiapine: 12.5-50 mg PO, fewer extrapyramidal effects
• Risperidone: 0.25-0.5 mg PO
• Olanzapine: 2.5-5 mg PO/IM

Other Medications

• Dexmedetomidine: For ICU delirium, sedation without respiratory depression
• Melatonin: May help regulate sleep-wake cycle
• Avoid benzodiazepines: Except for alcohol/benzodiazepine withdrawal

Monitoring and Follow-up

• Daily delirium assessments
• Monitor for medication side effects
• Assess for resolution of underlying causes
• Gradual medication taper as delirium resolves
• Cognitive assessment after recovery

Prevention

Preventing delirium is more effective than treating established cases. Multi-component interventions can reduce incidence by 30-40%.

Hospital-Based Prevention Programs

HELP (Hospital Elder Life Program)

• Orientation protocols
• Cognitive stimulation activities
• Sleep enhancement protocols
• Early mobilization
• Vision and hearing optimization
• Hydration and nutrition support

Perioperative Prevention

• Preoperative: Optimize medical conditions, medication review
• Intraoperative: Avoid long-acting sedatives, maintain homeostasis
• Postoperative: Early mobilization, pain control, avoid polypharmacy

Medication Management

• Regular medication reviews
• Avoid high-risk medications when possible
• Use lowest effective doses
• Monitor for drug interactions
• Consider prophylactic low-dose antipsychotics in high-risk cases

Family Education

• Recognize early signs of delirium
• Bring familiar objects from home
• Assist with orientation and reassurance
• Advocate for preventive measures

When to See a Doctor

Delirium is a medical emergency requiring immediate evaluation. Any acute change in mental status warrants urgent medical attention.

Seek Emergency Care For:

• Sudden confusion or disorientation
• Inability to recognize familiar people or places
• Hallucinations or paranoid behavior
• Extreme agitation or combativeness
• Sudden change in level of consciousness
• New difficulty speaking or understanding speech
• Accompanying fever, headache, or neck stiffness

High-Risk Situations

• Recent hospital discharge
• New medication started
• Recent surgery
• Known dementia with acute worsening
• Recent fall or head injury
• Signs of infection in elderly

Post-Delirium Care

After delirium resolves, follow-up is important for:

• Cognitive assessment
• Screening for persistent symptoms
• Medication review
• Prevention planning
• Family education and support

Related Conditions

Several conditions may present similarly to delirium or increase risk of developing delirium.

Frequently Asked Questions