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

Initial Approach to Altered Mental Status

The initial approach to a patient with altered mental status must prioritize the ABCs (Airway, Breathing, Circulation) followed by a systematic evaluation for life-threatening causes through focused history, physical examination, and targeted laboratory and imaging studies. 1

Primary Assessment (First Steps)

1. Stabilize vital functions:

   • Ensure airway patency and protection
   • Assess breathing adequacy and provide oxygen if needed
   • Evaluate circulation (blood pressure, heart rate, perfusion)
   • Check blood glucose level immediately

2. Obtain vital signs:

   • Temperature, pulse, blood pressure, respiratory rate, oxygen saturation 1
   • BMI assessment if feasible 2

3. Rapid neurological assessment:

   • Level of consciousness (AVPU: Alert, Voice, Pain, Unresponsive)
   • Pupillary response
   • Motor function and symmetry
   • Glasgow Coma Scale

Secondary Assessment

History (if available from patient, family, EMS, or records)

• Onset and progression of altered mental status
• Recent trauma, infections, or medical events
• Medication history (especially new medications, changes, or non-compliance)
• Substance use history
• Past medical history (especially neurological, psychiatric, endocrine disorders)
• Exposure to toxins or environmental factors
• Psychosocial stressors 2
• Family history of relevant conditions 2

Physical Examination

• General appearance and nutritional status 2
• Coordination and gait 2
• Skin examination for trauma, injection sites, rashes 2, 1
• Comprehensive neurological examination including:
  • Cranial nerve function
  • Motor and sensory function
  • Reflexes
  • Involuntary movements or abnormal motor tone 2
  • Signs of meningeal irritation
• Mental status examination assessing:
  • Mood and anxiety level
  • Thought content and process
  • Perception and cognition
  • Suicidal or homicidal ideation 2

Laboratory and Diagnostic Testing

First-line Laboratory Tests 1

• Complete blood count
• Basic metabolic panel
• Liver function tests
• Urinalysis
• Blood glucose
• Arterial blood gas (if respiratory distress)
• Toxicology screen (when indicated)
• Blood cultures (if febrile)

Additional Tests Based on Clinical Suspicion 1

• Ammonia levels (if hepatic encephalopathy suspected)
• Thyroid function tests
• Vitamin B12 levels (especially in elderly)
• Cerebrospinal fluid analysis (if meningitis/encephalitis suspected)

Imaging Studies 1

• CT head without contrast is the first-line imaging study
• MRI brain for further evaluation when indicated
• Chest X-ray if respiratory cause suspected

Common Etiologies to Consider 3

1. Neurological (35%) - stroke, seizure, intracranial hemorrhage
2. Toxicological (23%) - medication effects, illicit drugs, alcohol
3. Systemic/Organic (14.5%) - organ failure, hypoxia
4. Infectious (9.1%) - sepsis, meningitis, encephalitis
5. Endocrine/Metabolic (7.9%) - hypoglycemia, electrolyte abnormalities
6. Psychiatric (3.9%) - primary psychiatric disorders
7. Traumatic (2.1%) - head injury
8. Gynecologic/Obstetric (1.9%) - eclampsia, complications of pregnancy

Management Principles

1. Treat life-threatening conditions immediately:

   • Administer glucose for hypoglycemia
   • Provide naloxone for opioid overdose
   • Administer thiamine before glucose in suspected alcoholism
   • Treat seizures promptly with appropriate antiseizure medications 1

2. Address underlying causes:

   • Treat infections with appropriate antimicrobials
   • Correct metabolic derangements
   • Manage toxidromes with specific antidotes when available
   • Address organ dysfunction 1

3. Provide supportive care:

   • Maintain normothermia
   • Ensure adequate oxygenation and perfusion
   • Avoid physical restraints when possible
   • Implement reorientation strategies 1

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
• Premature diagnostic closure
• Missing nonconvulsive status epilepticus (consider EEG) 4

Special Considerations

• Elderly patients have higher mortality rates (10.8% vs. 6.9% in younger patients) 3
• Consider autoimmune encephalitis in otherwise unexplained altered mental status 4
• Continuous EEG monitoring may be necessary to identify nonconvulsive seizures 4
• Most patients with unexplained altered mental status require admission for further workup 1

Remember that altered mental status has a high fatality rate (8.1%) and requires prompt evaluation and treatment to decrease morbidity and mortality 3.