What is the initial approach to managing a patient with altered sensorium?

Initial Approach to Altered Sensorium

Begin with immediate assessment of airway, breathing, circulation, and rapid bedside glucose measurement, followed by systematic evaluation for life-threatening causes including hypoglycemia, hypoxia, infection, intracranial pathology, and metabolic derangements. 1, 2

Immediate Stabilization and Vital Assessment

• Secure airway and assess breathing if Glasgow Coma Scale ≤8 or patient cannot protect airway 3, 2
• Obtain fingerstick glucose immediately at bedside—hypoglycemia is rapidly reversible and life-threatening 1, 2
• Document vital signs systematically: fever suggests infection, hypotension suggests shock, hypertension may indicate intracranial pathology 2
• Quantify mental status objectively using Glasgow Coma Scale or FOUR score rather than subjective descriptors 2, 4
• Perform focused neurological examination specifically looking for focal deficits (asymmetric weakness, gaze preference, unequal pupils), as these significantly increase likelihood of structural brain lesion requiring immediate imaging 2

Critical History Elements

When obtaining history from patient, family, or emergency personnel, prioritize these specific details:

• Temporal profile: abrupt onset (minutes to hours) suggests stroke, seizure, or toxin; gradual onset (days) suggests metabolic or infectious cause 3, 1
• Medication and substance exposure: obtain complete list including over-the-counter medications, recent antibiotic use, alcohol, and illicit drugs 2
• Infectious symptoms: fever, headache, neck stiffness, recent infection, or sick contacts 1
• Comorbid conditions: diabetes (hypoglycemia/hyperglycemia), liver disease (hepatic encephalopathy), renal failure (uremia), malignancy 1, 2
• Recent trauma or falls, even minor, especially in elderly or anticoagulated patients 2

Initial Laboratory Workup

Order these tests immediately and simultaneously, not sequentially: 2

• Point-of-care glucose (if not already done)
• Complete metabolic panel: sodium, potassium, calcium, glucose, creatinine, blood urea nitrogen—electrolyte abnormalities cause 15-20% of altered sensorium cases 1, 2
• Complete blood count: evaluate for infection, anemia 2
• Liver function tests: AST, ALT, bilirubin, albumin 2
• Arterial blood gas: assess for hypoxia, hypercarbia (CO2 narcosis causes 17% of cases), acidosis 5
• Urinalysis and urine culture: urinary tract infection is common infectious trigger, especially in elderly 2
• Toxicology screen and acetaminophen level when substance use suspected or unclear history 3, 2
• Blood cultures if febrile 3

Do NOT routinely order ammonia levels—they are variable, may be elevated in non-hepatic conditions, and hepatic encephalopathy remains a diagnosis of exclusion even in cirrhotic patients 2

Neuroimaging Decision

Obtain non-contrast head CT immediately if ANY of the following are present: 2

• Focal neurological deficits (weakness, sensory loss, visual field cuts, cranial nerve abnormalities)
• History of head trauma or falls
• Anticoagulation use
• Headache with altered mental status
• Seizure activity
• Age >65 with unexplained altered sensorium
• History of malignancy
• Papilledema or signs of increased intracranial pressure

CT has 2-45% yield depending on risk factors present—the more risk factors, the higher the yield 2. Structural neurological causes account for 30-35% of altered sensorium cases and are the most common etiology 2, 5.

Consider MRI brain if CT negative but high clinical suspicion for encephalitis, posterior circulation stroke, or inflammatory conditions 2

Lumbar Puncture Considerations

Perform lumbar puncture when central nervous system infection suspected (fever, headache, neck stiffness, immunocompromised state) AFTER neuroimaging rules out mass effect 1

• Examine cerebrospinal fluid for cell count, protein, glucose, Gram stain, bacterial culture
• Add viral PCR panel (HSV, VZV, enterovirus) if encephalitis suspected 1

Empiric Treatment While Awaiting Results

Do not delay potentially life-saving treatments while awaiting diagnostic confirmation: 2

• Thiamine 500mg IV before glucose administration in malnourished, alcoholic, or at-risk patients to prevent Wernicke encephalopathy
• Naloxone if opioid toxicity suspected (pinpoint pupils, respiratory depression)
• Antibiotics and acyclovir if meningitis/encephalitis cannot be excluded—do not wait for lumbar puncture if delayed 1
• Treat hypoglycemia immediately with dextrose
• Correct severe electrolyte abnormalities (sodium <120 or >160, calcium <7 or >14) 1

Common Diagnostic Pitfalls to Avoid

• Never attribute altered sensorium to psychiatric causes without completing medical workup—history and physical examination have 94% sensitivity for identifying medical conditions 2
• Consider multiple concurrent etiologies, especially in elderly patients where delirium is often multifactorial and carries higher mortality 2
• Do not rely on short-term EEG—if nonconvulsive seizures suspected, continuous EEG monitoring is required as short-term EEG is statistically ineffective at detecting seizure activity 6
• Recognize that toxicologic/pharmacologic causes account for 20-25% of cases—medication side effects and polypharmacy are frequently overlooked 2

Specific Etiologies by Prevalence

Based on systematic evaluation, altered sensorium etiologies break down as: 2, 5

• Neurological (30-35%): stroke, intracranial hemorrhage, seizures, encephalitis, meningitis
• Toxicologic/Pharmacologic (20-25%): medication effects, alcohol, illicit drugs
• Metabolic (15-20%): hypoglycemia, hyperglycemia, electrolyte abnormalities, uremia, hepatic encephalopathy
• Infectious (9-18%): sepsis, urinary tract infection, pneumonia, CNS infections

Structural neurological causes are most common overall, making neuroimaging high-yield in appropriate patients 5.