How to approach a patient with altered sensorium?

Approach to the Patient with Altered Sensorium

Immediate Stabilization (First 5 Minutes)

Secure the airway immediately if Glasgow Coma Scale ≤8 or the patient cannot protect their airway—this is your highest priority to prevent aspiration and hypoxic brain injury. 1, 2

• Check fingerstick glucose at bedside before any other intervention, as hypoglycemia causes permanent neurological damage if untreated and is rapidly reversible 1, 2
• Administer thiamine 500mg IV before giving glucose in any patient with malnutrition, alcoholism, or risk factors to prevent precipitating Wernicke encephalopathy 1, 2
• Give IV dextrose immediately after thiamine if hypoglycemia is confirmed 2
• Administer naloxone if opioid toxicity is suspected based on pinpoint pupils, respiratory depression, or known substance use 1, 2

Vital Signs and Objective Assessment

Quantify mental status using Glasgow Coma Scale or FOUR score rather than subjective terms like "lethargic" or "confused." 1, 2

• Document temperature systematically: fever suggests infection, hypotension suggests shock/sepsis, hypertension may indicate intracranial pathology 1, 2
• Perform focused neurological examination specifically looking for focal deficits (asymmetric weakness, gaze deviation, pupillary asymmetry, unilateral sensory loss), as these substantially increase likelihood of structural brain lesion requiring urgent imaging 1, 2

Critical History Elements to Obtain

Prioritize temporal profile (sudden vs. gradual), complete medication list including over-the-counter drugs, recent antibiotic use, alcohol and illicit drugs, infectious symptoms, and recent trauma or falls. 1, 2

• Document comorbid conditions: diabetes, renal failure, liver disease, HIV/AIDS, malignancy 1, 3
• Ask specifically about headache, fever, neck stiffness, recent travel, tick exposure, and immunosuppression 3

Initial Laboratory Workup (Order Simultaneously)

Order point-of-care glucose, complete metabolic panel, complete blood count, liver function tests, and urinalysis immediately. 1, 2

• Add toxicology screen and acetaminophen level when substance use is suspected or history is unclear 1, 2
• Check for electrolyte abnormalities (hyponatremia, hypernatremia, hypocalcemia, hypercalcemia), uremia, and hepatic dysfunction 1, 3

Neuroimaging Decision Algorithm

Obtain non-contrast head CT immediately if ANY of the following are present: 1, 2

• Focal neurological deficits
• History of head trauma or falls
• Current anticoagulation use
• Age >60 with unexplained altered mental status

Consider MRI brain if CT is negative but high clinical suspicion exists for encephalitis, posterior circulation stroke, or inflammatory/autoimmune conditions. 1, 2

Lumbar Puncture Indications

Perform lumbar puncture when CNS infection is suspected, but only after neuroimaging rules out mass effect or increased intracranial pressure. 1, 2

• Send cerebrospinal fluid for: cell count with differential, protein, glucose, Gram stain, bacterial culture 1, 2
• Consider viral PCR panel if encephalitis is suspected 2

Empiric Treatment While Awaiting Results

Start empiric antibiotics and acyclovir immediately if meningitis or encephalitis cannot be excluded, even before lumbar puncture if there will be any delay. 1, 2

• Use vancomycin plus third-generation cephalosporin for suspected bacterial meningitis 2
• Add ampicillin if age >50 or immunocompromised 2
• Add acyclovir 10mg/kg IV every 8 hours for possible herpes simplex encephalitis 2

Common Etiologies by Prevalence

Understanding the frequency helps guide your diagnostic approach:

• Neurological causes: 30-35% (stroke, seizures, intracranial hemorrhage, mass lesions) 1, 4
• Toxicologic/pharmacologic: 20-25% (medications, alcohol, illicit drugs) 1
• Metabolic: 15-20% (hypoglycemia, electrolyte abnormalities, uremia, hepatic encephalopathy) 1, 3
• Infectious: 9-18% (meningitis, encephalitis, sepsis, endocarditis) 1, 3

Critical Pitfalls to Avoid

Never attribute altered sensorium to psychiatric causes without completing full medical workup—organic causes are far more common and missing them can be fatal. 1, 2

• Consider multiple concurrent etiologies, especially in elderly patients who may have baseline dementia plus acute infection plus medication effect 1, 2
• Recognize that medication reconciliation is essential since 20-25% of cases are toxicologic/pharmacologic 1
• Be aware that infective endocarditis presenting with altered sensorium may be due to intracranial mycotic aneurysm with 60% mortality 2
• Short-term EEG is ineffective in detecting nonconvulsive seizures; use continuous EEG monitoring if seizures are suspected, as nonconvulsive status epilepticus is associated with poor outcome 5