What is the recommended emergency department workup for a patient presenting with confusion and somnolence?

Emergency Department Workup for Confusion and Somnolence

Begin with immediate stabilization using the ABCDE approach: secure airway, assess breathing, check circulation, perform disability assessment (neurological exam and glucose), and expose the patient for full examination. 1, 2

Immediate Stabilization (First 5 Minutes)

• Check blood glucose immediately at bedside to rule out hypoglycemia as a reversible cause—this is the single most critical rapid intervention 1
• Assess and secure airway patency, particularly in somnolent patients at risk for aspiration 1, 2
• Apply pulse oximetry and provide supplemental oxygen only if oxygen saturation is <90-94%—do not give oxygen to normoxemic patients as hyperoxia may cause harm 1, 3
• Obtain vital signs including temperature, blood pressure, heart rate, and respiratory rate 1, 4
• Establish intravenous access 2

Rapid Neurological Assessment (Next 5 Minutes)

• Perform targeted neurological examination specifically looking for focal deficits (asymmetric weakness, gaze deviation, aphasia, visual field cuts) that suggest stroke or structural lesion 1
• Determine time of onset and last known well time to establish whether this is acute (hours), subacute (days), or chronic (weeks) 1
• Assess level of consciousness using Glasgow Coma Scale 2
• Check for meningeal signs (nuchal rigidity, Kernig's sign, Brudzinski's sign) if fever is present 1

Essential History (Concurrent with Above)

• Obtain collateral history from family, EMS, or nursing home staff to determine baseline cognitive function—this distinguishes acute delirium from chronic dementia 1, 5
• Review all medications with specific attention to: anticholinergics, benzodiazepines, opioids, sedatives, and any recently started medications 6, 1, 5
• Ask about recent falls, head trauma, fever, infectious symptoms, alcohol use, and drug use 6, 1
• In patients over 50 years, specifically ask about headache, scalp tenderness, jaw claudication, and vision changes to screen for giant cell arteritis 1

Mandatory Laboratory Testing

Order the following tests on all patients with confusion and somnolence:

• Complete blood count with differential to evaluate for infection and anemia 1
• Comprehensive metabolic panel including sodium, potassium, calcium, glucose, BUN, creatinine, and liver function tests 1
• Thyroid-stimulating hormone to exclude thyroid disorders 1
• Urinalysis and urine culture given high frequency of urinary tract infections as precipitants 1
• Electrocardiogram to evaluate for arrhythmias or ischemia 6

Selective Advanced Testing Based on Clinical Indicators

Neuroimaging (CT head non-contrast) is indicated when:

• Focal neurological deficits are present 1
• History of head trauma exists 6, 1
• Fever without clear source 1
• New-onset seizure 1
• Anticoagulation use 1

Note: The yield of neuroimaging in undifferentiated confusion is only 11%, so use selectively based on these specific indicators 1

Lumbar puncture is indicated when:

• Fever is present without clear source 1
• Meningeal signs are present 1
• Patient is immunocompromised 1
• Suspicion for subarachnoid hemorrhage with negative CT 1

Toxicology screen if drug intoxication or overdose is suspected based on history or physical findings 1

Erythrocyte sedimentation rate and C-reactive protein emergently in patients over 50 with headache, scalp tenderness, or visual symptoms suggesting giant cell arteritis 1

Delirium Screening

• Use the Confusion Assessment Method (CAM) to formally diagnose delirium 6, 1, 5
• The two-step process includes: (1) highly sensitive delirium triage screen, then (2) Brief Confusion Assessment Method for specificity 6
• Reassess regularly as mental status may fluctuate 6

Management of Agitation (If Present)

Non-pharmacological interventions first:

• Provide orientation cues (clocks, calendars, familiar objects) 1, 5
• Ensure adequate lighting and reduce excessive noise 1
• Encourage family presence when possible 1
• Avoid physical restraints as they worsen agitation 6, 1, 5

Pharmacological management only for severe agitation posing safety risk:

• Do NOT use haloperidol or risperidone for mild-to-moderate delirium—they have no benefit and may worsen symptoms 1
• Consider low-dose atypical antipsychotics (olanzapine, quetiapine, or aripiprazole) only for severe agitation that prevents essential medical care 1, 5
• Avoid benzodiazepines except in suspected alcohol or sedative withdrawal 6, 1, 5

Common Pitfalls to Avoid

• Do not attribute confusion solely to dementia without investigating for acute reversible causes—this is the most common error 5
• Do not assume bacteriuria with confusion always indicates urinary tract infection—confusion alone without fever or localizing symptoms may not indicate infection requiring antibiotics 5
• Do not administer sedatives without addressing the underlying cause 1
• Do not overlook medication side effects as potential causes, particularly anticholinergics and benzodiazepines 6, 1, 5