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

Initial Approach to a Patient with Altered Mental Status

The initial approach to a patient with altered mental status must prioritize airway protection, assessment of vital signs, and rapid evaluation for immediately life-threatening conditions including hypoglycemia, which should be checked in every patient with altered mental status. 1, 2

Initial Stabilization

• Assess and secure airway first to prevent aspiration, with transfer to a monitored setting if necessary 3
• Evaluate using validated scales such as Glasgow Coma Scale or Richmond Agitation Sedation Scale to objectively quantify severity 1, 2
• Check vital signs immediately, as abnormalities may indicate specific etiologies (fever suggesting infection, hypotension suggesting shock) 1, 2
• Check blood glucose levels in every septic patient with altered mental status; if unable to check glucose in a patient with impaired mental state, consider presumptive diagnosis of hypoglycemia and administer intravenous glucose 1

Focused History and Examination

• Document general appearance, coordination, gait, involuntary movements, and motor tone 1
• Evaluate for focal neurological deficits, which significantly increase likelihood of intracranial pathology requiring immediate neuroimaging 2
• Obtain comprehensive medication, drug, and alcohol history to identify potential toxicologic causes 2
• Assess mood, level of anxiety, thought content/process, perception, and cognition 1
• Evaluate for suicidal or homicidal ideation 1

Laboratory Investigations

• Obtain metabolic laboratory assessment including complete blood count, comprehensive metabolic panel, electrolytes, renal function, liver function tests, and urinalysis 2
• Consider toxicology screens when substance use is suspected 1, 2
• Note that history and physical examination have 94% sensitivity for identifying medical conditions, while laboratory studies alone have only 20% sensitivity 2

Neuroimaging

• Head CT without contrast is usually appropriate as first-line neuroimaging for patients with:
  • First episode of altered mental status
  • Focal neurological deficits
  • Seizures
  • New focal neurological signs 1, 2
• Brain MRI may be appropriate when CT is negative but clinical suspicion for intracranial pathology remains high 2

Common Etiologies to Consider

• Neurological causes (30-35%): intracranial mass, encephalitis, meningitis 2, 4
• Toxicologic/Pharmacologic causes (20-25%): medication side effects, alcohol intoxication, illicit drug use 2, 4
• Metabolic/Systemic causes (15-20%): hypoglycemia, hyperglycemia, electrolyte abnormalities, hepatic encephalopathy, uremia 2, 4
• Infectious causes (9-18%): sepsis, urinary tract infection, pneumonia, meningitis 2, 4

Special Considerations

• In elderly patients, delirium is often multifactorial and carries higher mortality; consider multiple concurrent etiologies 2, 5
• For patients with known intracranial pathology and worsening mental status, neuroimaging should be performed to assess for progression 2
• In patients with cirrhosis, hepatic encephalopathy is a common cause of altered mental status but remains a diagnosis of exclusion 2, 3

Pitfalls to Avoid

• Attributing altered mental status solely to psychiatric causes without adequate medical workup 2, 3
• Failing to check blood glucose levels in every patient with altered mental status 1
• Relying on ammonia levels alone to diagnose hepatic encephalopathy in cirrhotic patients 2, 3
• Delaying empiric treatment while awaiting diagnostic results in potentially life-threatening conditions 2, 3
• Missing delirium, which occurs in up to 10-31% of patients at admission and may develop in up to 56% of admitted patients 1