Delirium

See Also

Epidemiology
Incidence

Older, hospitalized adults: 30%
Older surgical patients: 10-50% (varies based on Frailty and procedure complexity)
1. Dyer (1995) Arch Intern Med 155:461-5 [PubMed]
Intensive Care unit: 70%
1. McNicoll 2003 J Am Geriatr Soc 51:591-8 [PubMed]
Emergency department: 10%
1. Elie 2000 CMAJ 163:977-81 [PubMed]

Definitions
Delirium

Acute Confusional State
Develops over hours to days
1. Contrast to Dementia with onset over months to years
Waxes and wanes and is reversible
1. Contrast to Dementia with a constant, progressive course (with minor fluctuations) and irreversible
2. Lewy Body Dementia, as an exception, may present with fluctuations
Inattention, disorganized thinking and altered level of consciosness
1. Contrast to Dementia in which attention and long-term memory are typically preserved

Types
Psychomotor

Hypoactive Delirium
1. Most common in the elderly and most commonly missed
2. Presents with at least 4 criteria
  1. Unawareness, decreased alertness or lethargy
  2. Sparse or slow speech, slow movements or staring
Hyperactive Delirium
1. See Agitated Delirium
2. Less common in the elderly
3. Presents with at least 3 criteria
  1. Hypervigilance, restlessness or anxiousness
  2. Fast or loud speech or swearing
  3. Irritability, impatience, combativeness, Agitation, anger or uncooperative
  4. Singing, laughing, euphoria
  5. Fast motor responses or easy startling
  6. Distractability, Tangentiality, persistent thoughts or Nightmares
Mixed Delirium
1. Mixed hyperactive and hypoactive features

Risk Factors
Comorobid Conditions

Age over 65 years (esp. male gender)
Underlying Dementia
Preexisting Major Depression
Drug Abuse
Chronic Pain
Alcohol Abuse and Alcohol Withdrawal
Prior brain injury (vascular or Traumatic Injury)
Hearing Loss
Decreased Visual Acuity
Insomnia or other sleep deprivation
Polypharmacy
Hospitalization or post-surgery
Multiple comorbid conditions
Poor nutritional status
Hepatic failure
Chronic Renal Failure
Poor functional status
Alcohol Abuse

Risk Factors
Precipitating Factors

Infectious (precipitates 50% of Delirium cases in elderly)
1. Precautions: Elderly with infectious causes
  1. Fever is absent in up to 20-30% of elderly patients with bacteremia
  2. Cough and fever are absent in 65% of elderly with Pneumonia
  3. Abdominal tenderness is absent in 65% of elderly with intra-abdominal infections
  4. Adedipe (2006) Emerg Med Clin North Am 24(2): 433-48 [PubMed]
2. Pneumonia
3. Urinary Tract Infection
4. Intraabdominal infection
5. Soft tissue infection (e.g. Pressure Ulcers)
6. Meningitis or Encephalitis
Cardiopulmonary
1. Myocardial Infarction (esp. elderly women and diabetics)
2. Congestive Heart Failure
3. Dehydration, Hemorrhage or other shock state
4. Hypoxia
5. Hypercarbia
Medications
1. See Medications to Avoid in Older Adults
2. See Medication Causes of Delirium in the Elderly
3. See Polypharmacy
4. Psychoactive medications, Anticholinergic Medications, Opioids or Benzodiazepines
5. More than 3 medications added within 24 hours
Endocrine and Metabolic
1. Electrolyte abnormalities (e.g. Hypercalcemia)
2. Acute Hepatic Failure (Hepatic Encephalopathy)
3. Acute Renal Failure (Uremic encephalopathy)
4. Hypoglycemia or Hyperglycemia
5. Thiamine deficiency (e.g. Wernicke Encephalopathy)
6. Hypothyroidism or Hyperthyroidism
Neuropsychiatric
1. Cerebrovascular Accident
2. Sleep deprivation
3. Seizure
4. CNS Hemorrhage (Subarachnoid Hemorrhage, Subdural Hematoma, Epidural Hematoma)
5. CNS Neoplasm
Iatrogenic
1. Physical Restraints
2. Indwelling Urinary Catheter
3. Other tethers (e.g. telemetry monitoring wires)
4. Medical procedures
  1. Postoperative State: 15 to 53% of elderly patients
  2. Hip Fracture: 28-61% of elderly patients
5. Intensive Care setting
  1. ICU with Mechanical Ventilation: 60-80% of elderly patients
  2. ICU without Mechanical Ventilation: 20-50% of elderly patients
Miscellaneous
1. Hypothermia or hyperthermia (e.g. Heat Stroke)
2. Toxin Induced Neurologic Changes

Causes
Life Threatening Delirium (Mnemonic - "WHHHHIMPS")

Wernicke Encephalopathy or Alcohol Withdrawal
Hypoxia or hypercarbia
Hypoglycemia
Hypertensive Encephalopathy
Hyperthermia or Hypothermia
Intracerebral Hemorrhage
Meningitis or Encephalitis
Poisoning (or iatrogenic medication induced)
Status Epilepticus

History
Obtain from family or Caregiver

Evaluate risk factors and causes as listed above
Home Medications
1. All bottles of currently taken medications should be brought to evaluation
Substance use
1. Alcohol Abuse
2. Benzodiazepine use

Exam

Review Vital Signs
1. See Toxin Induced Vital Sign Changes
Neurologic Exam
1. Careful and complete Neurologic Exam
Abdomen, Pelvis and Rectum
1. Occult abdominal infection (e.g. Diverticulitis, Appendicitis)
2. Perirectal Abscess
Skin Exam
1. Infected Decubitus Ulcer
Focus areas for cause
1. Hypoxia
2. Dehydration
3. Infection
4. Uncontrolled pain

Signs

Fluctuating levels of consciousness
1. Inattention
  1. The cornerstone of Delirium
  2. Unable to count backwards from 20 or name months or weekdays backwards
2. Perseveration
3. Decreased alertness
4. Disorientation
5. Extremes of activity (Somnolence to Agitation)
Disorganized Thought Processes
Memory Impairment (especially short term)
Perceptual disturbances
1. Persecutory Delusions are common
2. Visual Hallucinations rare except in organic cause
Emotional lability
Motor changes
1. Myoclonus
2. Asterixis

Labs
Initial

See Altered Level of Consciousness (includes labs)
All patients
1. Comprehensive metabolic panel (Electrolytes, Liver Function Tests, Renal Function tests)
2. Complete Blood Count
3. Urinalysis and Urine Culture
Other labs to consider
1. Thyroid Function Tests
2. Vitamin B12
3. Venous Blood Gas or Arterial Blood Gas
4. Blood Alcohol Level
5. Urine Drug Screen
6. Acetaminophen level
7. Salicylate level
8. Serum Ammonia
9. Lactic Acid
10. Medication levels (e.g. serum Lithium level or anticonvulsant level)
11. C-Reactive Protein (CRP) or Erythrocyte Sedimentation Rate (ESR)
12. Lumbar Puncture

Imaging

Chest XRay
1. Evaluate for occult Pneumonia
CT Head Indications
1. Focal neurologic deficit
2. Altered Level of Consciousness
3. Recent Head Trauma
4. Fever with encephalopathy
MRI Brain Indications
1. Persistent Delirium without obvious cause

Diagnostics

Electrocardiogram
1. Exclude QTc Prolongation and QRS Widening
Electroencephalogram
1. Diffuse slow waves

Evaluation

See Confusion Assessment Method
See Altered Level of Consciousness (includes labs)
See Richmond Agitation Sedation Scale (or RASS)
Focus areas
1. Key to evaluation is identifying underlying Delirium cause
2. Carefully review medication list and possible ingestions
3. Identify sources of infection including a full skin exam
4. Identify focal neurologic deficits
5. Identify subtle signs of Trauma

Evaluation
Urgent Indications

Dramatic Vital Sign change (with associated signs or symptoms)
1. Systolic Blood Pressure <90 mmHg
2. Heart Rate <50/min or >120/min
3. Respirations >30/min
4. Temperature <96 F (36 C) or >101 F (38 C)
Serious findings suggestive of underlying cause
1. New focal deficits
2. New respiratory distress (e.g. Hypoxia, Dyspnea)
3. Cerebrovascular Accident
4. Chest Pain
5. Hematuria
Serious psychiatric findings
1. See Agitated Delirium
2. Escalating aggressive behavior or threats of Violence
3. Persistent danger to self or others

Diagnosis
Criteria (DSM-5 Criteria)

Key criteria (all 5 must be present)
1. Disturbed awareness and attention
  1. Altered Level of Consciousness
  2. Altered content (e.g. inattention, lost focus)
2. Short duration of symptom onset (Hours to days)
  1. Rapid deterioration in all higher cortical functions
  2. Mental status fluctuates widely throughout the day
3. Altered cognition or Perception from baseline
  1. Decreased short-term memory, disturbed language or Perception (Hallucinations, Delusions)
4. History, exam or labs suggests medical cause, Intoxication or medication side effect
5. Not due to pre-existing Dementia (or related fluctuations such as sun downing)
Other factors may be associated
1. Psychomotor behavioral disturbance (e.g. change in activity, sleep)
2. Emotional disturbance (e.g. fear, depression, euphoria)
3. Autonomic Instability (Abnormal Vital Signs)
References
1. (2013) DSM-5, APA

Differential Diagnosis

Management
General

See Agitated Delirium
1. Emergent management to emergently de-escalate risk to patient and staff
See Agitation in Dementia
1. Provides a similar approach as for Agitated Delirium (esp. non-medication management)
Non-pharmacologic calming techniques are preferred
1. Provide a quiet, non-activating environment
2. Limit probes, beeping monitors, automatic Blood Pressure cuffs, bright lights
3. Limit multiple intravenous lines, nasal oxygen, Bladder catheters
4. Avoid Physical Restraints if at all possible
Admission for Delirium is generally warranted
1. Exception: Mild or resolved Delirium symptoms with reliable family and safe environment
  1. Discharge to home with close supervision and closer interval follow-up
2. Consider geriatric unit admission if available for Delirium in elderly patients

Management
Antipsychotics

Precautions
1. Antipsychotics are associated with increased mortality in the elderly
2. Avoid in Parkinsonism due to high risk of Extrapyramidal Side Effects
3. Use only short-term and only when non-pharmacologic measures fail
4. Limit to monitored settings
5. See each agent for contraindications and adverse effects before use
Agents: First-Line
1. Haloperidol 0.25 to 0.5 mg PO or IM every 4 hours (or 0.5 to 1.0 mg every 6 hours, maximum 30 mg/day)
Agents: Second-line
1. Risperidone (Risperdal) 0.5 mg orally twice daily
2. Olanzapine (Zyprexa) 2.5 to 5 mg orally twice daily (or 5 to 10 mg IM every 12 hours up to 30 mg/day)
3. Quetiapine (Seroquel) 25 mg orally twice daily (maximum 150 mg/day)
4. Ziprasidone (Geodon) 5 to 10 mg IM (maximum 40 mg/day)

Management
Benzodiazepines

Use with caution
1. May paradoxically exacerbate Agitation (esp. elderly)
Indications
1. Parkinsonism (in which Antipsychotics are avoided if possible due to Extrapyramidal Side Effects)
2. Drug Withdrawal or Alcohol Withdrawal
3. Neuroleptic Malignant Syndrome
Preparations
1. Lorazepam 0.5 to 1 mg orally or IV every 4 hours as needed

Course

Reversible in over 80% of cases

Prevention

Optimize hydration and nutrition
Early mobilization of patients
Avoid Sedatives for sleep (see Sleep Hygiene)
Reduce restraints and catheters
Reorient patient frequently (involve family presence)
Correct Vision (glasses) and Hearing (aids)
Avoid psychoactive and Anticholinergic Medications

Resources

Delirium and acute problematic behavior in the long-term care setting
1. http://www.guideline.gov/content.aspx?id=12379

References

Ho Han (2013) Crit Dec Emerg Med 27(11): 11-23
Khoujah and Magidson (2016) Crit Dec Emerg Med 30(10): 3-10 -Cole (2004) Am J Geriatr Psychiatry 12(1):7-21
Inouye (2006) N Engl J Med 354(11): 1157-65 [PubMed]
Kalish (2014) Am Fam Physician 90(3): 150-8 [PubMed]
Miller (2008) Am Fam Physician 78(11): 1265-70 [PubMed]