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Delirium, Emergency Medicine

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, Оі-aminobutyric acid, and serotonin may be involved.

- Neurologic: - Meningitis or encephalitis - Seizure - Wernicke encephalopathy - Hypoxia and hypoperfusion of the brain - Intracranial bleed or mass

- Cardiovascular: - Hypertensive crisis - Acute coronary syndromes - Arrhythmia

- Renal: - Endocrine: - Hypoglycemia - Hyperglycemia - Hypothyroid

- 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

- Medications: - Prescribed, over-the-counter and illicit drugs - Dosing - Recently added medications - Recently discontinued medications

- Further studies based on signs and symptoms: - Arterial blood gas - Thyroid-stimulating hormone - Cardiac enzymes

- Document basic neurologic exam: - Glasgow coma scale score - Pupils - Extremity movements

  • 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 dysfunctionDerangements of cerebral acetylcholineCNS dopamine, Оі-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 encephalitisSeizureWernicke encephalopathyHypoxia and hypoperfusion of the brainIntracranial bleed or mass
  • Pulmonary:PneumoniaOther pulmonary etiology of hypoxia
  • Cardiovascular:Hypertensive crisisAcute coronary syndromesArrhythmia
  • GI:Hepatic encephalopathyDehydration
  • Renal:
  • Endocrine:HypoglycemiaHyperglycemiaHypothyroid
  • Rheumatologic:Collagen vascular disorder
  • Toxicologic:Environmental toxinsMedicationsWithdrawal from barbiturates or alcohol
  • Other:Electrolyte abnormalitiesVitamin deficienciesHypothermiaHyperthermiaTrauma
  • 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:DisorientationImpaired memoryDisorganized thinking and speechMisperceptions, illusions, delusions, and hallucinations
  • Reduced awareness of environment
  • Inattention:Difficulties in focusing, shifting, and maintaining attentionRestlessnessDistractibilityLability

History

  • History from caregivers is essential.
  • Time course:Hours to daysFluctuating course
  • Medications:Prescribed, over-the-counter and illicit drugsDosingRecently added medicationsRecently 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 statusOrientationFocal deficitsHallucinations
  • 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 course2: Inattention3: Disorganized thinking4: Altered level of consciousnessDiagnosis is made when features 1 and 2 are present with either 3 or 4Mini-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, calciumRenal functionHepatic functionGlucoseCBCUrinalysis with culture and sensitivityToxicology screens
  • Further studies based on signs and symptoms:Arterial blood gasThyroid-stimulating hormoneCardiac 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 measurementECG monitoring
  • Naloxone if associated respiratory insufficiency
  • Monitor patient:Advanced life support (ALS) transport with all medications
  • Look for signs of an underlying cause:MedicationsMedical alert bracelets
  • Document basic neurologic exam:Glasgow coma scale scorePupilsExtremity 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: пїЅ

  • 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 пїЅJH, Zimmerman пїЅEE, Cutler пїЅN, et al. Delirium in older emergency department patients: Recognition, risk factors, and psychomotor subtypes. Acad Emerg Med. 2009;16:193-200.
  • Inouye пїЅSK. Delirium in older persons. N Engl J Med. 2006;354:1157-1165.
  • Lonergan пїЅE, Luxenberg пїЅJ, Areosa Sastre пїЅA. 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)