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Emergency And Acute Medicine – Delirium
Basics And Description
Delirium is an acute clinical syndrome marked by sudden changes in awareness, cognition, and perception, with a fluctuating, waxing-and-waning course. It is not a primary disease but a manifestation of an underlying medical condition. The exact pathophysiology is unknown, though it is thought to involve diffuse cerebral dysfunction and disturbances in neurotransmitters, particularly decreased cerebral acetylcholine and altered dopamine, γ-aminobutyric acid (GABA), and serotonin activity. Delirium is frequently overlooked in the emergency department because patients often present with atypical or vague complaints. It is associated with increased inpatient mortality and longer hospital stays.
Etiology
Neurologic causes include meningitis, encephalitis, seizures, Wernicke encephalopathy, hypoxia or hypoperfusion of the brain, and intracranial hemorrhage or mass lesions. Pulmonary causes include pneumonia and other conditions leading to hypoxia. Cardiovascular etiologies include hypertensive crisis, acute coronary syndromes, and arrhythmias. Gastrointestinal causes include hepatic encephalopathy and dehydration. Renal causes include urinary tract infection and acute renal failure. Endocrine disorders include hypoglycemia, hyperglycemia, and hypothyroidism. Rheumatologic causes include collagen vascular diseases. Toxicologic causes include environmental toxins, medications, and withdrawal from alcohol or barbiturates. Other causes include electrolyte abnormalities, vitamin deficiencies, hypothermia, hyperthermia, and trauma.
Geriatric Considerations
Delirium is common in older emergency department patients, with up to 10% affected. Presentations are often subtle, with complaints such as falls, dizziness, or a general sense of not feeling well. Symptoms frequently fluctuate, and the underlying cause may be a life-threatening condition.
Diagnosis – Signs And Symptoms
Disturbances of consciousness may be hyperactive, hypoactive, or mixed. Hyperactive delirium presents with agitation and combativeness, while hypoactive delirium presents with lethargy, stupor, or coma. Mixed states may rapidly alternate between the two. Cognitive changes include disorientation, impaired memory, disorganized thinking and speech, reduced environmental awareness, misperceptions, illusions, delusions, and hallucinations. Inattention is a key feature, with difficulty focusing, sustaining, or shifting attention. Patients may also demonstrate restlessness, distractibility, and emotional lability.
History
Collateral history from caregivers is essential. Key elements include the time course, typically hours to days, and a fluctuating pattern. A thorough medication history is critical, including prescribed, over-the-counter, and illicit substances, recent medication changes, and withdrawals. Associated symptoms and pre-existing medical conditions may point toward the underlying etiology.
Physical Examination
Vital signs should be carefully assessed. A complete neurologic examination is essential, with attention to mental status, orientation, focal deficits, and hallucinations. A psychiatric assessment and cardiovascular, pulmonary, and gastrointestinal examinations should be performed to identify potential sources of infection, sepsis, or other systemic illness.
Screening Tools
Several tools can aid in identifying delirium. The Confusion Assessment Method includes four features: acute onset or fluctuating course, inattention, disorganized thinking, and altered level of consciousness. Delirium is diagnosed when features one and two are present along with either three or four. The Mini-Mental State Examination may be used serially, though patient cooperation can limit its utility in the emergency setting.
Essential Workup
Recognizing delirium as a syndrome is critical. The diagnostic approach should be broad and guided by history, physical examination, and clinical suspicion to identify the underlying organic cause.
Diagnosis Tests And Interpretation
Initial laboratory testing should include electrolytes, calcium, renal function, hepatic function, glucose, complete blood count, urinalysis with culture, and toxicology screening. Additional tests may include arterial blood gas analysis, thyroid-stimulating hormone, and cardiac enzymes. Imaging studies often include ECG, chest radiograph, and head CT. Further imaging is guided by clinical findings. Diagnostic procedures such as lumbar puncture or EEG are performed when indicated, particularly if infection or seizure activity is suspected.
Differential Diagnosis
Delirium must be distinguished from psychiatric illness, which typically lacks fluctuating consciousness and is more often associated with auditory hallucinations. Dementia is characterized by a slow, progressive decline without acute fluctuation or changes in consciousness. Once delirium is identified, the differential diagnosis for its underlying cause remains extensive.
Treatment – Prehospital Care
Establish IV access and monitor oxygen saturation and cardiac rhythm. Check blood glucose. Administer naloxone if respiratory insufficiency is suspected. Provide advanced life support transport as needed. Look for clues to the underlying cause, such as medications or medical alert identification, and document a baseline neurologic examination including Glasgow Coma Scale score, pupillary response, and extremity movement.
Emergency Department Treatment And Procedures
Management focuses on identifying and treating the underlying cause. Provide IV access, supplemental oxygen if hypoxic, and continuous cardiac, pulse oximetry, and blood pressure monitoring. Administer thiamine to alcoholic or malnourished patients. In severely agitated patients, short-term pharmacologic control may be necessary to allow safe evaluation and treatment.
Medication Management
Treatment is directed at the underlying etiology. Benzodiazepines are first-line therapy for alcohol or benzodiazepine withdrawal but should be avoided in most other causes of delirium if possible. Before administering antipsychotics, assess for prolonged QT interval. Haloperidol 5–10 mg IV or IM may be used, with lower doses recommended for elderly patients. Atypical antipsychotics may be equally effective. Thiamine 100 mg IV, IM, or PO should be given when indicated. Second-line agents include alprazolam 0.25–0.5 mg PO or lorazepam 0.5–2 mg IV, IM, or PO.
Follow-Up And Disposition
Admission is indicated when the cause of delirium is unclear or symptoms persist. Discharge may be considered if a treatable cause is identified and corrected, mental status returns to baseline in the emergency department, reliable caregivers are available, and follow-up is assured.
Follow-Up Recommendations
Follow-up depends on the underlying condition. If delirium resolves during the emergency visit, close follow-up with a primary care provider is recommended, ideally within two days. Patients and caregivers must receive clear return precautions, as any recurrence of delirium warrants immediate reevaluation.
Key Clinical Lessons And Common Errors
Prompt identification of the underlying cause is essential. Delirium is frequently missed in the emergency department, and maintaining awareness of delirium as a medical syndrome is critical, as it may signal a life-threatening condition.
Basics And Description
Delirium is an acute clinical syndrome marked by sudden changes in awareness, cognition, and perception, with a fluctuating, waxing-and-waning course. It is not a primary disease but a manifestation of an underlying medical condition. The exact pathophysiology is unknown, though it is thought to involve diffuse cerebral dysfunction and disturbances in neurotransmitters, particularly decreased cerebral acetylcholine and altered dopamine, γ-aminobutyric acid (GABA), and serotonin activity. Delirium is frequently overlooked in the emergency department because patients often present with atypical or vague complaints. It is associated with increased inpatient mortality and longer hospital stays.
Etiology
Neurologic causes include meningitis, encephalitis, seizures, Wernicke encephalopathy, hypoxia or hypoperfusion of the brain, and intracranial hemorrhage or mass lesions. Pulmonary causes include pneumonia and other conditions leading to hypoxia. Cardiovascular etiologies include hypertensive crisis, acute coronary syndromes, and arrhythmias. Gastrointestinal causes include hepatic encephalopathy and dehydration. Renal causes include urinary tract infection and acute renal failure. Endocrine disorders include hypoglycemia, hyperglycemia, and hypothyroidism. Rheumatologic causes include collagen vascular diseases. Toxicologic causes include environmental toxins, medications, and withdrawal from alcohol or barbiturates. Other causes include electrolyte abnormalities, vitamin deficiencies, hypothermia, hyperthermia, and trauma.
Geriatric Considerations
Delirium is common in older emergency department patients, with up to 10% affected. Presentations are often subtle, with complaints such as falls, dizziness, or a general sense of not feeling well. Symptoms frequently fluctuate, and the underlying cause may be a life-threatening condition.
Diagnosis – Signs And Symptoms
Disturbances of consciousness may be hyperactive, hypoactive, or mixed. Hyperactive delirium presents with agitation and combativeness, while hypoactive delirium presents with lethargy, stupor, or coma. Mixed states may rapidly alternate between the two. Cognitive changes include disorientation, impaired memory, disorganized thinking and speech, reduced environmental awareness, misperceptions, illusions, delusions, and hallucinations. Inattention is a key feature, with difficulty focusing, sustaining, or shifting attention. Patients may also demonstrate restlessness, distractibility, and emotional lability.
History
Collateral history from caregivers is essential. Key elements include the time course, typically hours to days, and a fluctuating pattern. A thorough medication history is critical, including prescribed, over-the-counter, and illicit substances, recent medication changes, and withdrawals. Associated symptoms and pre-existing medical conditions may point toward the underlying etiology.
Physical Examination
Vital signs should be carefully assessed. A complete neurologic examination is essential, with attention to mental status, orientation, focal deficits, and hallucinations. A psychiatric assessment and cardiovascular, pulmonary, and gastrointestinal examinations should be performed to identify potential sources of infection, sepsis, or other systemic illness.
Screening Tools
Several tools can aid in identifying delirium. The Confusion Assessment Method includes four features: acute onset or fluctuating course, inattention, disorganized thinking, and altered level of consciousness. Delirium is diagnosed when features one and two are present along with either three or four. The Mini-Mental State Examination may be used serially, though patient cooperation can limit its utility in the emergency setting.
Essential Workup
Recognizing delirium as a syndrome is critical. The diagnostic approach should be broad and guided by history, physical examination, and clinical suspicion to identify the underlying organic cause.
Diagnosis Tests And Interpretation
Initial laboratory testing should include electrolytes, calcium, renal function, hepatic function, glucose, complete blood count, urinalysis with culture, and toxicology screening. Additional tests may include arterial blood gas analysis, thyroid-stimulating hormone, and cardiac enzymes. Imaging studies often include ECG, chest radiograph, and head CT. Further imaging is guided by clinical findings. Diagnostic procedures such as lumbar puncture or EEG are performed when indicated, particularly if infection or seizure activity is suspected.
Differential Diagnosis
Delirium must be distinguished from psychiatric illness, which typically lacks fluctuating consciousness and is more often associated with auditory hallucinations. Dementia is characterized by a slow, progressive decline without acute fluctuation or changes in consciousness. Once delirium is identified, the differential diagnosis for its underlying cause remains extensive.
Treatment – Prehospital Care
Establish IV access and monitor oxygen saturation and cardiac rhythm. Check blood glucose. Administer naloxone if respiratory insufficiency is suspected. Provide advanced life support transport as needed. Look for clues to the underlying cause, such as medications or medical alert identification, and document a baseline neurologic examination including Glasgow Coma Scale score, pupillary response, and extremity movement.
Emergency Department Treatment And Procedures
Management focuses on identifying and treating the underlying cause. Provide IV access, supplemental oxygen if hypoxic, and continuous cardiac, pulse oximetry, and blood pressure monitoring. Administer thiamine to alcoholic or malnourished patients. In severely agitated patients, short-term pharmacologic control may be necessary to allow safe evaluation and treatment.
Medication Management
Treatment is directed at the underlying etiology. Benzodiazepines are first-line therapy for alcohol or benzodiazepine withdrawal but should be avoided in most other causes of delirium if possible. Before administering antipsychotics, assess for prolonged QT interval. Haloperidol 5–10 mg IV or IM may be used, with lower doses recommended for elderly patients. Atypical antipsychotics may be equally effective. Thiamine 100 mg IV, IM, or PO should be given when indicated. Second-line agents include alprazolam 0.25–0.5 mg PO or lorazepam 0.5–2 mg IV, IM, or PO.
Follow-Up And Disposition
Admission is indicated when the cause of delirium is unclear or symptoms persist. Discharge may be considered if a treatable cause is identified and corrected, mental status returns to baseline in the emergency department, reliable caregivers are available, and follow-up is assured.
Follow-Up Recommendations
Follow-up depends on the underlying condition. If delirium resolves during the emergency visit, close follow-up with a primary care provider is recommended, ideally within two days. Patients and caregivers must receive clear return precautions, as any recurrence of delirium warrants immediate reevaluation.
Key Clinical Lessons And Common Errors
Prompt identification of the underlying cause is essential. Delirium is frequently missed in the emergency department, and maintaining awareness of delirium as a medical syndrome is critical, as it may signal a life-threatening condition.
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