How should I evaluate and manage a 78‑year‑old patient with new‑onset confusion suggestive of acute delirium?

Evaluation and Management of Acute Confusion in a 78-Year-Old Patient

Immediately screen for delirium using the Confusion Assessment Method (CAM) and simultaneously begin investigating reversible causes, as delirium is a medical emergency with mortality rates twice as high when missed. 1

Initial Diagnostic Approach

Use Validated Screening Tools First

• Apply the Confusion Assessment Method (CAM) to objectively diagnose delirium, which has 82-100% sensitivity and 89-99% specificity 2, 3
• Screen every 8-12 hours (at least once per shift) because cognitive status fluctuates substantially throughout the day 1, 2
• Critical pitfall: Without validated screening tools, clinicians fail to recognize delirium in the majority of cases 2

Obtain Collateral History Immediately

• Interview a knowledgeable informant to establish the patient's baseline cognitive function, the acute onset timeline (hours to days), and whether symptoms fluctuate 1
• Determine if pre-existing dementia exists, as delirium commonly occurs superimposed on dementia 1, 4
• Review the complete medication list, focusing on recent additions or dose changes, particularly anticholinergics, sedatives, opioids, antipsychotics, and vasodilators 2
• Assess for alcohol use and withdrawal risk, as symptoms typically begin 6-24 hours after cessation and peak at 3-5 days 3
• Document any recent falls, head trauma, or loss of consciousness 2

Distinguish Delirium from Dementia

The key distinguishing features are: 1

• Delirium: Acute onset (hours to days), fluctuating course, disordered attention and consciousness, hallucinations often present
• Dementia: Insidious onset, constant course, attention generally preserved until advanced stages

Essential Laboratory Workup

Perform targeted laboratory testing guided by clinical evaluation rather than extensive routine batteries. 2

Core Laboratory Panel

Order these tests in all or almost all patients: 1, 5, 2

• Complete blood count (evaluate for infection or hematologic abnormalities)
• Comprehensive metabolic panel (assess electrolytes, renal and liver function)
• Blood glucose (rule out hypo/hyperglycemia)
• Urinalysis (screen for urinary tract infection—the most common precipitating infection along with pneumonia) 1, 5, 2
• Thyroid-stimulating hormone (TSH)
• Vitamin B12 level

Additional Testing Based on Clinical Suspicion

• Toxicology screen if substance intoxication or withdrawal suspected 5
• Medication levels when appropriate (especially psychotropic medications) 5
• Electrocardiogram to assess for myocardial ischemia or arrhythmias 5, 2
• Chest radiography if pneumonia suspected 5, 2

Neuroimaging Indications

Perform brain CT or MRI selectively, not routinely, guided by specific clinical features. 1, 5, 2

Obtain neuroimaging if any of these are present:

• Focal neurological deficits 5, 2
• History of recent head trauma 5, 2
• New-onset seizures 5, 2
• Signs of increased intracranial pressure 5, 2
• Unexplained altered mental status despite initial workup 5, 2

MRI is preferred when available, though practical challenges exist with agitated patients 5

Most Common Reversible Causes to Investigate

Infections (Most Frequent Precipitating Factor)

• Urinary tract infection 1, 5, 2
• Pneumonia 1, 5, 2
• Other systemic infections 1

Medications

• Anticholinergic medications 1, 2
• Sedatives/hypnotics 2
• Opioids 2
• Recent medication changes or polypharmacy effects 2

Metabolic and Physiologic Disturbances

• Electrolyte and hydration disturbances 1
• Hypoxia 1
• Organ failure (renal, hepatic) 1
• Dehydration 1

Management Strategy

Non-Pharmacological Interventions (First-Line)

Implement these measures immediately: 1, 5

• Frequently reassure and reorient the patient using easily visible calendars and clocks
• Provide adequate pain control
• Maximize oxygen delivery (supplemental oxygen, blood pressure support as needed)
• Use sensory aids (glasses, hearing aids) as appropriate
• Regulate bowel/bladder function
• Increase supervised mobility
• Maintain normal sleep-wake cycles
• Create a calm, therapeutic environment

Pharmacological Management

• Minimize chemical restraints whenever possible 1
• When absolutely necessary for safety or distressing symptoms, haloperidol is recommended over lorazepam for acute treatment 1, 5
• Avoid medications with anticholinergic properties 6

Treat Underlying Causes

• Target identified reversible causes (infection, medication adjustment, metabolic correction) 5, 2
• Prevent/promptly treat dehydration and electrolyte disturbances 1
• Eliminate or minimize identified risk factors 1

Critical Pitfalls to Avoid

Hypoactive Delirium

This is the most commonly missed diagnosis. 1, 5, 2

• Presents with cognitive and motor slowing, sedated appearance
• More common in older individuals
• Associated with greater risk of morbidity and mortality 1
• Frequently mistaken for depression or fatigue 2

Other Common Errors

• Attributing acute symptoms to pre-existing dementia without investigating reversible causes 5, 2
• Inadequate screening leading to missed diagnosis 5, 2
• Mistaking delirium for primary psychiatric disorders 5
• Failing to obtain collateral history from knowledgeable informants 1

Psychiatric Consultation

Obtain psychiatric consultation for all patients with delirium, especially when primary psychosis cannot be excluded 5