Basics
Description
- Delirium is a clinical syndrome characterized by acute changes in awareness, cognition, and perception with a waxing and waning course.
- Delirium is a syndrome secondary to an underlying medical condition.
- Pathophysiology unknown:
- Diffuse cerebral dysfunction
- Derangements of cerebral acetylcholine
- CNS dopamine, γ-aminobutyric acid, and serotonin may be involved.
- Frequently missed by emergency medicine physicians due to atypical chief complaints.
- Associated with increased mortality for inpatients and increased length of stay.
Etiology
- Neurologic:
- Meningitis or encephalitis
- Seizure
- Wernicke encephalopathy
- Hypoxia and hypoperfusion of the brain
- Intracranial bleed or mass
- Pulmonary:
- Pneumonia
- Other pulmonary etiology of hypoxia
- Cardiovascular:
- Hypertensive crisis
- Acute coronary syndromes
- Arrhythmia
- GI:
- Hepatic encephalopathy
- Dehydration
- Renal:
- Endocrine:
- Hypoglycemia
- Hyperglycemia
- Hypothyroid
- Rheumatologic:
- Collagen vascular disorder
- Toxicologic:
- Environmental toxins
- Medications
- Withdrawal from barbiturates or alcohol
- Other:
- Electrolyte abnormalities
- Vitamin deficiencies
- Hypothermia
- Hyperthermia
- Trauma
- Common presentation in older ED patients
- Up to 10% of older ED patients may have delirium.
- Many patients will present with subtle symptoms and vague chief complaints:
- Fall, dizzy, or not feeling well
- Waxing and waning symptoms
- Cause may be life-threatening condition.
Diagnosis
Signs and Symptoms
- Disturbed consciousness:
- Hyperalert:
- Hypoactive:
- Can have mixed hyperalert and hypoactive state with rapid oscillations
- Cognitive changes:
- Disorientation
- Impaired memory
- Disorganized thinking and speech
- Misperceptions, illusions, delusions, and hallucinations
- Reduced awareness of environment
- Inattention:
- Difficulties in focusing, shifting, and maintaining attention
- Restlessness
- Distractibility
- Lability
History
- History from caregivers is essential.
- Time course:
- Hours to days
- Fluctuating course
- Medications:
- Prescribed, over-the-counter and illicit drugs
- Dosing
- Recently added medications
- Recently discontinued medications
- Associated signs, symptoms, pre-existing conditions that would indicate underlying etiology
Physical Exam
- Vital signs
- Complete neurologic exam:
- Careful attention to changes in mental status
- Orientation
- Focal deficits
- Hallucinations
- Psychiatric exam
- Cardiovascular, pulmonary, GI systems.
- Use physical exam to determine possible underlying medical illness and to focus further workup, especially sources of infection and sepsis.
- Several screening tools are available to evaluate for delirium:
- Confusion assessment method consists of 4 key features:
- 1: Acute onset or fluctuating course
- 2: Inattention
- 3: Disorganized thinking
- 4: Altered level of consciousness
- Diagnosis is made when features 1 and 2 are present with either 3 or 4
- Mini-mental state exam:
- Can be administered serially and will fluctuate; formal cognitive assessment may be difficult to accomplish due to patient cooperation.
Essential Workup
- Awareness of delirium as syndrome is key.
- Workup should be broad to determine underlying organic disease.
- Ancillary studies as determined by history, physical, and initial workup
Diagnosis Tests & Interpretation
Lab
- Initial testing:
- Electrolytes, calcium
- Renal function
- Hepatic function
- Glucose
- CBC
- Urinalysis with culture and sensitivity
- Toxicology screens
- Further studies based on signs and symptoms:
- Arterial blood gas
- Thyroid-stimulating hormone
- Cardiac enzymes
Imaging
- ECG
- Head CT scan
- CXR
- Other imaging based on history, physical exam, and possible etiologies
Diagnostic Procedures/Surgery
- As indicated by potential underlying cause
- Lumbar puncture if indicated
- EEG if indicated by potential seizure activity
Differential Diagnosis
- Other disease processes that should be distinguished from delirium include:
- Psychiatric illness:
- Symptoms do not have fluctuating course that is typical of delirium.
- Usually there are no changes in level of consciousness.
- Delirium is classically associated with visual hallucinations and psychiatric illness with auditory hallucinations.
- Dementia:
- Delirium has rapid onset, while dementia has a slowly progressive, insidious course without fluctuation of symptoms.
- Dementia is not associated with acute changes in consciousness.
- Once identified as delirium, the differential for the underlying cause is quite extensive.
Treatment
Pre-Hospital
- IV access:
- Pulse oximetry to monitor respiratory status:
- Glucose measurement
- ECG monitoring
- Naloxone if associated respiratory insufficiency
- Monitor patient:
- Advanced life support (ALS) transport with all medications
- Look for signs of an underlying cause:
- Medications
- Medical alert bracelets
- Document basic neurologic exam:
- Glasgow coma scale score
- Pupils
- Extremity movements
Ed Treatment/Procedures
- When delirium is identified, seek the underlying cause intensely.
- Treatment should be targeted at underlying medical condition.
- IV line access
- Oxygen if indicated by hypoxia
- Cardiac, pulse oximetry, and BP monitoring
- Thiamine should be administered to alcoholic and malnourished patients.
- In patients who are significantly agitated, chemical treatment of agitation may help facilitate ED workup.
Medication
- Treatment of delirium should be aimed at underlying condition.
- Benzodiazepines should be 1st line for patients with alcohol or benzodiazepine withdrawal.
- Benzodiazepines should be avoided in patients with all other causes of delirium, if possible.
First Line
- Assess the patient for prolonged QT syndrome before administering antipsychotic agents. Haloperidol: 5-10 mg IV or IM:
- Lower doses (0.5-2 mg) are appropriate for elderly patients.
- Recent studies show that atypical antipsychotics may be equally effective to typical antipsychotics.
- Thiamine: 100 mg IV, IM, or PO
Second Line
- Alprazolam: 0.25-0.5 mg PO
- Lorazepam: 0.5-2 mg IV, IM, or PO
Follow-Up
Disposition
Admission Criteria
- When cause is unclear, admit.
- If delirium has not resolved, admit.
Discharge Criteria
Patient could be discharged if: �
- Treatable cause is found and treated
- Mental status clears while in the ED
- Reliable caregivers are available
- Follow-up is ensured
Follow-Up Recommendations
- Follow-up depends on underlying condition.
- When delirium has resolved within ED stay, close follow-up with primary care provider, preferably in <2 days.
- Patients and caregivers should be counseled carefully regarding return precautions:
- Any recurrence of delirium should prompt a return to the ED.
- Delirium can be a life-threatening condition.
Pearls and Pitfalls
- Identify underlying cause
- Delirium is often missed by emergency physicians and maintaining an awareness of delirium as a syndrome is critical.
Additional Reading
- Han �JH, Zimmerman �EE, Cutler �N, et al. Delirium in older emergency department patients: Recognition, risk factors, and psychomotor subtypes. Acad Emerg Med. 2009;16:193-200.
- Inouye �SK. Delirium in older persons. N Engl J Med. 2006;354:1157-1165.
- Lonergan �E, Luxenberg �J, Areosa Sastre �A. Benzodiazepines for delirium. Cochrane Database Syst Rev. 2009;(4):CD006379.
Codes
ICD9
- 291.0 Alcohol withdrawal delirium
- 293.0 Delirium due to conditions classified elsewhere
- 780.09 Other alteration of consciousness
- 292.81 Drug-induced delirium
- 290.11 Presenile dementia with delirium
- 290.3 Senile dementia with delirium
ICD10
- F05 Delirium due to known physiological condition
- F10.231 Alcohol dependence with withdrawal delirium
- R41.0 Disorientation, unspecified
SNOMED
- 2776000 Delirium (disorder)
- 191505005 Acute confusional state, of cerebrovascular origin (disorder)
- 8635005 alcohol withdrawal delirium (disorder)
- 191492000 Drug-induced delirium (disorder)