What is the approach to a patient presenting with altered sensorium, considering their age, sex, socioeconomic status, pre-existing conditions, allergies, and current medications?

Approach to Altered Sensorium

Immediately secure the airway if Glasgow Coma Scale ≤8, check fingerstick glucose at bedside before any other intervention, and obtain non-contrast head CT urgently if focal deficits, head trauma, anticoagulation use, or age >60 are present. 1, 2, 3

Immediate Stabilization (First 5 Minutes)

Airway and Breathing

• Intubate immediately if GCS ≤8 or inability to protect airway to prevent aspiration and hypoxic brain injury 2, 3
• Assess respiratory pattern and oxygen saturation, as abnormal breathing may indicate brainstem dysfunction or metabolic derangement 2

Critical Bedside Interventions (In This Order)

• Check fingerstick glucose immediately before any other test - hypoglycemia causes permanent neurological damage if untreated and is rapidly reversible 2, 3
• Administer thiamine 500mg IV before giving glucose in any patient with malnutrition, alcoholism, or risk factors to prevent precipitating Wernicke encephalopathy 2, 3
• Give IV dextrose immediately after thiamine if hypoglycemia confirmed 2
• Administer naloxone if opioid toxicity suspected based on pinpoint pupils, respiratory depression, or known substance use 2, 3

Vital Signs Documentation

• Document temperature (fever suggests infection), blood pressure (hypotension suggests shock/sepsis, hypertension suggests intracranial pathology), heart rate, and respiratory rate 2, 3
• Quantify mental status using Glasgow Coma Scale or FOUR score rather than subjective terms like "lethargic" or "confused" 1, 2, 3
• Perform focused neurological examination specifically looking for focal deficits, as these substantially increase likelihood of structural brain lesion requiring urgent imaging 1, 2, 3

Critical History Elements

Temporal Profile and Exposures

• Obtain temporal profile: acute (minutes to hours) versus subacute (days) versus chronic (weeks) 4, 2, 3
• Complete medication list including over-the-counter medications, recent antibiotics, alcohol, and illicit drugs - toxicologic/pharmacologic causes account for 20-25% of cases 2, 3
• Recent trauma or falls history 2, 3

Infectious and Medical History

• Infectious symptoms: fever, headache, neck stiffness, rash, recent tick exposure 4, 2, 3
• Comorbid conditions: diabetes, renal failure, liver disease, HIV/AIDS, malignancy, known dementia 4, 2, 3
• Current anticoagulation use 1, 2, 3

Initial Laboratory Workup (Order Simultaneously)

• Point-of-care glucose 2, 3
• Complete metabolic panel (sodium, potassium, calcium, glucose, BUN, creatinine) 2, 3
• Complete blood count 2, 3
• Liver function tests 2, 3
• Urinalysis 2, 3
• Toxicology screen and acetaminophen level when substance use suspected or history unclear 2, 3
• Arterial blood gas if metabolic acidosis suspected 4

Neuroimaging Decision Algorithm

Obtain Non-Contrast Head CT Immediately If ANY of the Following:

• Focal neurological deficits 1, 2, 3
• History of head trauma or falls 1, 2, 3
• Current anticoagulation use 1, 2, 3
• Age >60 with unexplained altered mental status 1, 2, 3
• New seizure activity 1
• Severe headache 1

When CT is Negative But High Clinical Suspicion Exists

• Consider MRI brain for encephalitis, posterior circulation stroke, or inflammatory/autoimmune conditions 2, 3
• MRI more sensitive than CT for detecting early ischemic changes, encephalitis, and posterior fossa pathology 1

Yield of Neuroimaging

• CT head detects acute contributory findings in 11% of atraumatic altered mental status cases overall 1
• Yield increases to 16.5% in febrile elderly patients 1
• Most common findings: intracranial hemorrhage and ischemic stroke 1

Lumbar Puncture Protocol

When to Perform

• Perform when CNS infection suspected, but only after neuroimaging rules out mass effect or increased intracranial pressure 2, 3
• Indications: fever with altered sensorium, meningismus, immunocompromised state, subacute presentation with headache 4, 2

CSF Studies to Send

• Cell count with differential 2, 3
• Protein and glucose 2, 3
• Gram stain and bacterial culture 2, 3
• Viral PCR panel if encephalitis suspected (HSV, VZV, enterovirus) 2
• Consider autoimmune encephalitis panel if clinical suspicion (anti-NMDA, anti-LGI1) 5

Empiric Treatment While Awaiting Results

Suspected Meningitis/Encephalitis

• Start empiric antibiotics and acyclovir immediately if meningitis or encephalitis cannot be excluded, even before lumbar puncture if any delay 2, 3
• Vancomycin plus third-generation cephalosporin (ceftriaxone or cefotaxime) for suspected bacterial meningitis 2
• Add ampicillin if age >50 or immunocompromised (for Listeria coverage) 2
• Acyclovir 10mg/kg IV every 8 hours for possible herpes simplex encephalitis 2

Status Epilepticus Management

• Lorazepam 4mg IV slowly (2mg/min) for patients ≥18 years 6
• If seizures continue after 10-15 minutes, give additional 4mg IV slowly 6
• Equipment for airway management must be immediately available as respiratory depression is the most important risk 6
• Maintain unobstructed airway and have artificial ventilation equipment ready 6

Common Etiologies by Prevalence

• Neurological causes: 30-35% (stroke, seizure, intracranial hemorrhage, CNS infection) 3
• Toxicologic/pharmacologic: 20-25% (medications, alcohol, illicit drugs) 2, 3
• Metabolic: 15-20% (hypoglycemia, hyponatremia, uremia, hepatic encephalopathy) 4, 3
• Infectious: 9-18% (sepsis, meningitis, encephalitis, systemic infections) 4, 3

Critical Pitfalls to Avoid

Never Assume Psychiatric Cause

• Never attribute altered sensorium to psychiatric causes without completing full medical workup - organic causes are far more common and missing them can be fatal 2, 3
• Even patients with known psychiatric illness require medical clearance with selective testing guided by clinical evaluation 3

Consider Multiple Concurrent Etiologies

• Elderly patients may have baseline dementia plus acute infection plus medication effect simultaneously 2, 3
• Delirium in elderly requires investigation for multiple concurrent causes including medications, infections, and metabolic derangements 3

Recognize Hypoactive Delirium

• Hypoactive delirium presents with cognitive and motor slowing rather than agitation, is more common in elderly, carries higher mortality, but is frequently missed 3

Special High-Risk Scenarios

• Infective endocarditis with altered sensorium may indicate intracranial mycotic aneurysm with 60% mortality - may present with headache, altered sensorium, or focal deficits before catastrophic rupture 2
• Cirrhotic patients require concurrent airway protection, investigation of cause, treatment of precipitating factors, and empiric therapy for hepatic encephalopathy 3
• Short-term EEG is ineffective in detecting seizures - continuous EEG monitoring provides independent prognostic information and should be used when nonconvulsive seizures suspected 7