Author:
Lori A.Stolz
Arthur B.Sand ers
Description
- Delirium is a clinical syndrome characterized by acute changes in awareness, cognition, and perception with a waxing and waning course
- Delirium is often secondary to an underlying acute 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
- Associated with increased mortality, increased admission, and increased length of stay
Etiology
- Neurologic:
- Meningitis or encephalitis
- Seizure
- Wernicke encephalopathy
- Hypoxia and hypoperfusion of the brain
- Intracranial bleed or mass
- Stroke syndrome
- Pulmonary:
- Pneumonia
- Other pulmonary etiology of hypoxia or hypercapnia
- Cardiovascular:
- Hypertensive crisis
- Acute coronary syndromes
- Arrhythmia
- GI:
- Hepatic encephalopathy
- Dehydration
- Renal:
- Endocrine:
- Hypoglycemia
- Hyperglycemia
- Hypothyroid
- Rheumatologic:
- Collagen vascular disorder
- Toxicologic:
- Medications or supplements
- Withdrawal from barbiturates or alcohol
- Environmental toxins
- Other:
- Electrolyte abnormalities
- Vitamin deficiencies
- Hypothermia
- Hyperthermia
- Trauma
- Surgery
Geriatric Considerations |
- 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
- Patients with known dementia are prone to develop delirium from acute medical conditions
- Life-threatening condition
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Signs and Symptoms
- Disturbed consciousness:
- Hyperalert:
- Hypoactive:
- Can have mixed hyperalert and hypoactive state with rapid oscillations
- Hypoactive state is under-recognized
- 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 to establishing time course and fluctuating symptoms
- 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, falls, or trauma that may indicate underlying etiology
Physical Exam
- Use physical exam to determine possible underlying medical illness and to focus further workup, especially sources of infection and sepsis
- Vital signs
- Complete neurologic exam:
- Careful mental status exam
- Cranial nerves, motor, and coordination
- Focal deficits
- Hallucinations or delusions
- Psychiatric exam
- Cardiovascular, pulmonary, GI, and full skin exam
- Several screening tools are available to evaluate for delirium:
- Most delirium assessment tools are not validated in the ED
- 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
Diagnostic Tests & Interpretation
Lab
- Initial testing:
- Electrolytes, calcium, magnesium, phosphorus
- Renal function
- Hepatic function
- Glucose
- CBC
- Urinalysis with culture and sensitivity
- Thyroid-stimulating hormone
- Toxicology screens
- Further studies based on signs and symptoms:
- Arterial blood gas
- Cardiac enzymes
Imaging
- ECG
- Head CT scan/MRI in selected patients
- 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 may distinguish delirium from nonconvulsive status epilepticus
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
Disposition
Admission Criteria
- When cause is unclear, admit
- If delirium has not resolved, admit
- Patients discharged with unidentified delirium have high mortality
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 d
- 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
