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

Approach to Altered Mental Status

Immediate Stabilization (First 5 Minutes)

Secure the airway immediately in any patient with Glasgow Coma Scale <8 or Grade 3-4 altered mental status, as airway protection is the absolute first priority to prevent aspiration. 1, 2, 3

• Transfer patients with GCS <8 to ICU-level monitoring immediately 1, 2
• Intubate if: inability to maintain airway, massive GI bleeding, or respiratory distress 1, 2, 3
• Use short-acting sedatives (propofol or dexmedetomidine) instead of benzodiazepines to preserve cognitive assessment and reduce ventilation duration 1, 2, 3
• Stabilize vital signs concurrently with airway management 2

Concurrent Diagnostic Assessment (Do Not Delay Treatment)

Obtain head CT without contrast immediately if this is a first episode of altered mental status, or if there are focal neurological deficits, seizures, increased intracranial bleeding risk, or hypertensive emergency. 4, 2, 3

Essential Laboratory Workup

• Draw comprehensive metabolic panel including: CBC, electrolytes, glucose, renal function, liver function tests, and urinalysis 1, 3
• Obtain toxicology screens and drug/alcohol levels based on history 1
• Do NOT routinely measure ammonia levels - they are variable, unreliable, and should not guide diagnosis of hepatic encephalopathy 1, 3

Neuroimaging Algorithm

• First-line: Head CT without contrast for first episode, focal deficits, seizures, bleeding risk, or hypertensive emergency 4, 2, 3
• Second-line: Brain MRI if CT negative but clinical suspicion for intracranial pathology remains high 3
• Do NOT obtain routine brain imaging in clinically stable psychiatric patients (alert, cooperative, normal vitals, noncontributory history/physical) 4

Systematic Etiologic Investigation by Prevalence

The most common causes in order of frequency are: 1, 2, 5

1. Neurological (30-35%): Stroke, seizure, intracranial hemorrhage, mass lesion 1, 2, 5
2. Toxicologic/Pharmacologic (20-25%): Drug intoxication, withdrawal, medication side effects 1, 2, 5
3. Metabolic/Systemic (15-20%): Hepatic encephalopathy, uremia, electrolyte disorders 1, 2, 5
4. Infectious (9-18%): Sepsis, meningitis, encephalitis, UTI 1, 2, 5

History and Physical Examination Targets

• History and physical examination have 94% sensitivity for identifying medical conditions - this is far superior to laboratory testing alone (20% sensitivity) 1, 2
• Examine specifically for: focal neurological deficits (significantly increase likelihood of intracranial pathology), signs of trauma, toxidromes, infection sources, and vital sign abnormalities 4, 2
• Interview patient and collateral sources separately when possible, as patients frequently minimize symptoms 4

Empiric Treatment (Start While Awaiting Diagnostics)

For Suspected Encephalitis

• Start IV acyclovir 10 mg/kg three times daily immediately, especially in immunocompromised patients - do not wait for diagnostic confirmation 2, 3
• Consider encephalitis even with prolonged history, subtle features, no fever, or normal CSF white cell count in immunocompromised patients 3

For Suspected Hepatic Encephalopathy

• Initiate lactulose or polyethylene glycol immediately - approximately 90% of patients improve with correction of precipitating factor alone 1, 2, 3
• Add rifaximin for patients not responding to lactulose alone 1, 3
• Hepatic encephalopathy remains a diagnosis of exclusion - always investigate alternative causes including alcohol intoxication, infections, and electrolyte disorders in cirrhotic patients 1, 3

For Cardiogenic Shock with AMS

• Give fluid challenge (saline or ringer lactate >200 mL over 15-30 minutes) if no overt fluid overload 3
• Consider dobutamine to increase cardiac output if needed 3

Critical Medications to Avoid

• Avoid or minimize opioids, benzodiazepines, and gabapentin due to synergistic sedating effects that worsen mental status 1, 3
• In cirrhotic patients, avoid all sedating medications as they can precipitate or worsen hepatic encephalopathy 1, 3

Special Population Considerations

Elderly Patients

• Consider multiple concurrent etiologies - delirium in elderly is often multifactorial with significantly higher mortality 1, 2, 3
• Mortality doubles if delirium diagnosis is missed 1

Psychiatric Presentations

• Never attribute altered mental status solely to psychiatric causes without completing medical workup 4, 1, 2
• Routine laboratory and radiographic testing is low yield in clinically stable psychiatric patients (alert, cooperative, normal vitals, noncontributory exam) 4
• For patients with concerning findings (altered mental status, unexplained vital sign abnormalities, new-onset or acute psychiatric symptom changes), perform careful evaluation for underlying medical conditions 4

Critical Pitfalls to Avoid

• Never rely on ammonia levels alone to diagnose hepatic encephalopathy in cirrhotic patients 1, 2, 3
• Never skip thorough clinical assessment - history and physical have 94% sensitivity versus 20% for labs alone 1, 2
• Never delay empiric treatment while awaiting diagnostic results in potentially life-threatening conditions 1, 2, 3
• Never assume single etiology - always consider multiple concurrent causes, especially in elderly patients 1, 2, 3
• Never obtain routine brain CT in young patients with new-onset psychosis and normal neurological exam - yield is extremely low and equivalent to general population 4

Monitoring Requirements

• Transfer to ICU if: respiratory rate >25, SaO₂ <90%, use of accessory muscles, systolic BP <90 mmHg, or signs of hypoperfusion 3
• Standard monitoring includes: pulse, respiratory rate, blood pressure, daily weights, and accurate fluid balance 3
• Periodically monitor serum electrolytes in patients receiving diuretic therapy during treatment 6