What is the initial workup and management for a patient with altered mental status?

Initial Workup and Management for Altered Mental Status

The initial workup for altered mental status should focus on airway protection, rapid assessment of vital signs, and investigation of common reversible causes through targeted laboratory testing and neuroimaging when indicated. 1

Immediate Assessment and Stabilization

Airway Management

• Assess airway patency and protect if compromised
• Consider intubation for patients with:
  • Inability to maintain airway
  • Massive upper GI bleeding
  • Respiratory distress 2
• Have equipment necessary to maintain patent airway immediately available 3

Vital Signs Assessment

• Complete set of vital signs: temperature, blood pressure, heart rate, respiratory rate, oxygen saturation
• Assess level of consciousness using Glasgow Coma Scale (GCS)
• Check for focal neurological deficits, pupillary response, and meningeal signs 1

Laboratory Investigations

First-Line Laboratory Tests

• Complete blood count
• Basic metabolic panel (electrolytes, glucose, BUN, creatinine)
• Liver function tests
• Urinalysis
• Blood cultures (if febrile)
• Thyroid function tests 1

Second-Line Laboratory Tests (Based on Clinical Suspicion)

• Toxicology screen and blood alcohol level
• Ammonia level (if liver disease suspected)
• HIV testing
• Vitamin B12 level
• Arterial blood gases (if respiratory compromise) 1, 2

Neuroimaging

Head CT Without Contrast

• Indicated for:
  • First episode of altered mental status
  • Presence of focal neurological deficits
  • History of trauma
  • Seizures
  • Severe headache
  • Anticoagulant use
  • Immunocompromised state 1

Brain MRI Without and With IV Contrast

• Superior for detecting:
  • Small ischemic infarcts
  • Subtle cases of subarachnoid hemorrhage
  • Encephalitis
  • Focal cerebral edema
• Consider after initial stabilization if CT is negative but clinical suspicion remains high 1

Common Etiologies to Consider

Neurological (35.0%)

• Stroke/TIA
• Seizures (including nonconvulsive status epilepticus)
• Intracranial hemorrhage
• Meningitis/encephalitis 4

Toxicological/Pharmacological (23.0%)

• Medication side effects
• Alcohol intoxication or withdrawal
• Drug overdose or withdrawal 4

Systemic/Organic (14.5%)

• Hypoxia
• Shock
• Organ failure 4

Infectious (9.1%)

• Sepsis
• Urinary tract infection
• Pneumonia 4

Metabolic/Endocrine (7.9%)

• Hypoglycemia or hyperglycemia
• Electrolyte abnormalities
• Thyroid disorders
• Hepatic encephalopathy 4

Special Considerations

Hepatic Encephalopathy

For patients with known cirrhosis:

• Investigate precipitating factors
• Consider empiric lactulose treatment
• Avoid routine ammonia testing
• For sedation, use short-acting medications like propofol or dexmedetomidine
• Avoid benzodiazepines and minimize opioids 2

Status Epilepticus

• Administer lorazepam 4 mg IV slowly (2 mg/min) for adults
• If seizures continue after 10-15 minutes, give additional 4 mg IV
• Start IV fluids, monitor vital signs, maintain airway 3

Common Pitfalls to Avoid

• Premature diagnostic closure before considering full differential
• Overreliance on normal neuroimaging
• Missing subtle presentations of serious conditions
• Inadequate documentation of mental status changes
• Excessive laboratory testing without clinical direction 1
• Failing to recognize medication side effects 1
• Attributing symptoms to one cause without considering multiple contributing factors 5

Management Algorithm

1. Assess and stabilize ABCs (Airway, Breathing, Circulation)
2. Check vital signs and glucose (treat hypoglycemia if present)
3. Perform focused neurological examination
4. Order first-line laboratory tests
5. Consider neuroimaging based on clinical presentation
6. Treat identified causes:
   • For seizures: administer anticonvulsants
   • For infections: start empiric antibiotics
   • For metabolic derangements: correct electrolyte abnormalities
   • For hepatic encephalopathy: administer lactulose
   • For toxin/medication effects: consider antidotes or supportive care

Remember that altered mental status has a high mortality rate (8.1%), with higher rates in elderly patients (10.8% vs. 6.9% in younger patients) 4. Early identification and treatment of the underlying cause is essential to improve outcomes.