What is the initial evaluation and management of a patient with altered mental status?

Initial Evaluation and Management of Altered Mental Status

Airway protection is the absolute first priority, followed immediately by systematic investigation of underlying causes while initiating empiric therapy for life-threatening reversible conditions. 1, 2

Immediate Stabilization (First 15 Minutes)

Assess and secure the airway immediately - patients with Grade 3-4 altered mental status or Glasgow Coma Scale <8 require ICU-level monitoring and potential intubation. 1, 2 Specific indications for intubation include:

• Inability to maintain airway protection 2
• Massive upper GI bleeding 2
• Respiratory distress 2

If sedation is required for intubation, use propofol or dexmedetomidine instead of benzodiazepines - these short-acting agents preserve cognitive function and reduce ventilation duration. 1, 2

Check fingerstick glucose immediately - hypoglycemia is rapidly reversible and potentially fatal if missed. 1, 2

Concurrent Diagnostic Workup

Essential Laboratory Testing

Obtain comprehensive metabolic assessment immediately, including: 1, 2

• Complete blood count
• Comprehensive metabolic panel (electrolytes, glucose, renal function, liver function)
• Urinalysis
• Toxicology screens based on history 1

Do NOT routinely measure ammonia levels - they are variable, unreliable, and a normal value does not exclude hepatic encephalopathy in cirrhotic patients. 1, 2

Neuroimaging Strategy

Head CT without contrast is the first-line imaging for patients with: 2

• First episode of altered mental status
• Focal neurological deficits
• Seizures
• Increased risk for intracranial bleeding
• Hypertensive emergency

Brain MRI should be obtained when CT is negative but clinical suspicion for intracranial pathology remains high. 2

Systematic Etiologic Investigation

The most common causes follow a predictable pattern: 1

• Neurological (30-35%) - stroke, seizures, intracranial hemorrhage
• Toxicologic/pharmacologic (20-25%) - medication effects, intoxication
• Infectious (9-18%) - sepsis, meningitis, encephalitis
• Metabolic/systemic (15-20%) - electrolyte abnormalities, organ failure

History and physical examination have 94% sensitivity for identifying medical conditions - do not skip thorough clinical assessment despite the urgency. 1

Critical Pitfall to Avoid

Never attribute altered mental status solely to psychiatric causes without completing the medical workup - this is the most common diagnostic error and doubles mortality if delirium is missed. 1, 2

Empiric Treatment Approach

Identifying and treating precipitating factors is crucial - approximately 90% of patients improve with correction of the precipitating factor alone. 1

Specific Empiric Therapies

For suspected encephalitis in immunocompromised patients:

• Start intravenous aciclovir (10 mg/kg three times daily) immediately while awaiting diagnostic results 3
• Consider encephalitis even with prolonged history, subtle features, no fever, or normal CSF white cell count 3

For cirrhotic patients with suspected hepatic encephalopathy:

• Initiate lactulose or polyethylene glycol 1
• Consider rifaximin as add-on therapy for non-responders 1, 2
• Remember this is a diagnosis of exclusion - investigate alcohol intoxication, infections, and electrolyte disorders first 1

For cardiogenic shock with altered mental status (defined as SBP <90 mmHg with oliguria, cold peripheries, lactate >2 mmol/L, or metabolic acidosis):

• Fluid challenge (saline or ringer lactate >200 mL over 15-30 minutes) as first-line if no overt fluid overload 3
• Dobutamine to increase cardiac output if needed 3

Medication Management

Avoid or minimize these medications due to synergistic sedating effects: 1

• Opioids
• Benzodiazepines
• Gabapentin

Monitoring Requirements

Transfer to ICU if any of the following are present: 3

• Respiratory rate >25
• SaO₂ <90%
• Use of accessory muscles for breathing
• Systolic BP <90 mmHg
• Signs of hypoperfusion (oliguria, cold peripheries, altered mental status, lactate >2 mmol/L, metabolic acidosis, SvO₂ <65%)

Standard monitoring should include: 3

• Pulse, respiratory rate, blood pressure
• Daily weights and accurate fluid balance
• Daily renal function and electrolytes

Special Populations

In immunocompromised patients:

• Perform LP even with normal immune status (don't wait for HIV test results) 3
• CT head before LP only if severe immunocompromise 3
• CSF investigations should be performed regardless of CSF cell count - these patients often have acellular CSF despite serious CNS infection 3

In elderly patients:

• Delirium is often multifactorial 1, 2
• Death rate is significantly higher (10.8% vs 6.9% in younger patients) 4

Prognosis

Overall mortality for hospitalized patients with altered mental status is 8-11%, with mortality doubling if delirium diagnosis is missed. 1, 5 The mean hospital length of stay is approximately 11-12 days. 5