What is the initial approach to working up a patient with altered mental status?

Initial Approach to Working Up Altered Mental Status

The initial approach to altered mental status should include immediate assessment of airway, breathing, and circulation, followed by rapid evaluation for life-threatening causes through focused laboratory testing (CBC, metabolic panel, toxicology screen), and treatment of reversible conditions such as hypoglycemia, hypoxia, or opioid overdose. 1

Primary Assessment and Stabilization

1. Ensure patent airway and adequate ventilation

   • Have equipment immediately available to maintain airway 1
   • Provide oxygen for hypoxia 1

2. Assess and stabilize circulation

   • Monitor vital signs
   • Establish IV access for medication administration and fluid resuscitation

3. Immediate interventions for life-threatening conditions 1

   • Administer glucose for hypoglycemia
   • Provide oxygen for hypoxia
   • Give naloxone for suspected opioid overdose

Diagnostic Workup

Essential Laboratory Tests 1

• Complete blood count (identifies infections, anemia)
• Basic metabolic panel (electrolyte disturbances, renal function)
• Liver function tests (hepatic encephalopathy)
• Urinalysis (urinary tract infections)
• Toxicology screen (substance-induced altered mental status)
• Thyroid function tests (especially in elderly)
• Blood cultures (if febrile)
• Ammonia levels (if hepatic encephalopathy suspected)

Neuroimaging Considerations 1

• Indicated for patients with:
  • Focal neurological deficits
  • New or worsening headaches
  • History of head trauma
  • Atypical presentation
  • First-episode altered mental status without clear cause

Common Etiologies to Consider

The most common causes of altered mental status include 1, 2:

1. Neurological (35%)

   • Stroke, seizures, CNS lesions, neurodegenerative disorders

2. Toxicological (23%)

   • Medication effects, substance intoxication or withdrawal
   • Look for specific toxidromes (serotonin syndrome, neuroleptic malignant syndrome, anticholinergic poisoning) 1

3. Systemic/Organic (14.5%)

   • Organ dysfunction, hypoxia, shock

4. Infectious (9.1%)

   • Sepsis, meningitis, encephalitis

5. Endocrine/Metabolic (7.9%)

   • Hypoglycemia, electrolyte disturbances, thyroid disorders

6. Psychiatric (3.9%)

   • Rule out medical causes before attributing to psychiatric etiology

7. Traumatic (2.1%)

   • Head injury, post-concussive syndrome

Management Approach

1. Treat underlying causes 1

   • Administer antibiotics for suspected infections
   • Correct metabolic derangements
   • Treat seizures promptly with appropriate antiseizure medications
   • Avoid medications that worsen encephalopathy (benzodiazepines, opioids)

2. Supportive care 1

   • Maintain normothermia
   • Ensure adequate oxygenation and perfusion
   • Avoid physical restraints when possible
   • Provide reorientation strategies

3. Admission criteria 1

   • Admit patients with:
     • Unexplained altered mental status
     • Severe physiological derangements
     • Need for close neurological monitoring

Special Considerations

Elderly Patients

• Higher risk of abnormal brain imaging 1
• Consider additional testing for B12 deficiency and thyroid disorders 1
• Higher mortality rate (10.8% vs 6.9% in younger patients) 2

Common Pitfalls to Avoid 1

• Attributing behavioral changes to psychiatric causes without adequate medical workup
• Overreliance on neuroimaging before basic laboratory testing
• Missing atypical presentations of common infections in elderly patients
• Failure to recognize medication side effects or interactions

Monitoring and Follow-up

• Regularly assess for changes in status
• Perform periodic imaging if clinically indicated 1
• Implement a multidisciplinary approach including neurology, physical therapy, occupational therapy, speech therapy, and nutritional support as needed 1

Remember that up to 46% of patients with altered mental status have medical illnesses directly causing or exacerbating their presentation 1, making a thorough medical workup essential before attributing symptoms to psychiatric causes.