Altered mental status

This page is for adult patients. For pediatric patients, see: altered mental status (peds)

Background

• Altered mental status (AMS) is one of the most common and challenging presentations in the ED
• Encompasses a spectrum from mild confusion to deep coma
• May include alteration of arousal (level of consciousness), awareness, thought content, memory, or attention
• Both cerebral cortices or the brainstem reticular activating system must be affected
• Key distinctions:
  • Delirium: Acute, fluctuating alteration in attention and awareness; typically reversible
  • Dementia: Chronic, progressive cognitive decline; not typically an ED diagnosis
  • Psychiatric: Diagnosis of exclusion — always rule out organic causes first
• Must quickly determine if the altered state is from diffuse (metabolic/toxic) or focal (structural/vascular) impairment

Clinical Features

• History from family/EMS/bystanders is critical:
  • Baseline mental status and functional level
  • Onset (sudden vs gradual), preceding symptoms, recent medications/substances
  • Medical history: diabetes, liver/kidney disease, seizures, psychiatric history, substance use
• Physical exam priorities:
  • Vital signs: Fever (infection, toxidrome), hypothermia, hypo/hypertension, tachycardia, hypoxia
  • Glucose: Point-of-care immediately
  • Neurologic exam:
    • Level of consciousness (Glasgow Coma Scale)
    • Pupil size and reactivity
    • Focal deficits (hemiparesis, facial droop, gaze preference) → suggests structural lesion
    • Diffuse findings (no lateralizing signs) → suggests metabolic/toxic cause
  • Skin: Needle tracks, jaundice, rash (meningococcemia, petechiae), diaphoresis, dryness
  • Odor: Alcohol, fruity (DKA), fetor hepaticus
  • Meningeal signs: Nuchal rigidity (meningitis, SAH)

Differential Diagnosis

Altered mental status

Diffuse brain dysfunction

• Hypoxic encephalopathy
• Acute toxic-metabolic encephalopathy (Delirium)
  • Hypoglycemia
  • Hyperosmolar state (e.g., hyperglycemia)
  • Electrolyte Abnormalities (hypernatremia or hyponatremia, hypercalcemia)
  • Organ system failure
  • Hepatic Encephalopathy
  • Uremia/Renal Failure
  • Endocrine (Addison's disease, Cushing syndrome, hypothyroidism, myxedema coma, thyroid storm)
  • Hypoxia
  • CO2 narcosis
• Hypertensive Encephalopathy
• Toxins
• TTP / Thrombotic thrombocytopenic purpura
• Alcohol withdrawal
• Drug reactions (NMS, Serotonin Syndrome)
• Environmental causes
  • Hypothermia
  • Hyperthermia
• Deficiency state
  • Wernicke encephalopathy
  • Subacute Combined Degeneration of Spinal Cord (B12 deficiency)
  • Vitamin D Deficiency
  • Zinc Deficiency
• Sepsis
• Osmotic demyelination syndrome (central pontine myelinolysis)
• Limbic encephalitis

Primary CNS disease or trauma

• Direct CNS trauma
  • Diffuse axonal injury
  • Subdural/epidural hematoma
• Vascular disease
  • Intraparenchymal hemorrhage
• SAH
• Stroke
  • Hemispheric, brainstem
• CNS infections
  • Encephalitis
  • Anti-NMDA receptor encephalitis
  • Meningitis
• Neoplasms
  • Paraneoplastic Limbic encephalitis
  • Malignant Meningitis
  • Pancreatic Insulinoma
• Seizures
  • Nonconvulsive status epilepticus
  • Postictal state
• Dementia
  • Alzheimer's
  • Lewy Body Dementia
  • Frontotemporal Dementia

Psychiatric

• Acute psychosis
• Catatonia
• Excited delirium
• Malingering
• Steroid induced psychosis

Evaluation

AMS Workup

Common Orders

• Point of care glucose
• CBC
• Chemistry
• LFTs
• UA
• CXR
• Utox
• ECG
• Head CT
• CAM score

Consider Based on Clinical Situation

• Blood and urine cultures
• Ammonia level
• Tylenol/Aspirin level
• LP
• Serum Osm
• Coags
• Cortisol
• ABG/VBG
• CO level

• Additional workup based on clinical suspicion:
  • CT head without contrast — if trauma, focal deficits, no clear metabolic cause, or concern for hemorrhage
  • Lumbar puncture — if meningitis/encephalitis suspected (after CT if indicated)
  • EEG — if nonconvulsive status epilepticus suspected (prolonged postictal state, subtle motor activity)
  • CT angiography — if acute stroke suspected
  • Toxicology screen — urine drug screen; consider serum levels (ethanol, salicylate, acetaminophen, lithium)
  • Blood gas (VBG/ABG) — for acid-base disturbances, CO levels
  • Ammonia — if hepatic encephalopathy suspected
  • Thyroid function — if no other cause identified (myxedema coma, thyroid storm)
  • Cortisol — if adrenal crisis suspected

Management

• ABCs first:
  • Protect airway — intubate if GCS ≤8 or unable to protect airway
  • O2, IV access, continuous monitoring
• Immediate interventions:
  • Dextrose (D50 50 mL IV or D10 titrated) if hypoglycemic
  • Thiamine 100 mg IV (give before or with glucose)
  • Naloxone 0.4-2 mg IV if opioid toxicity suspected
• Patients with focal findings may have a surgically treatable cause → emergent imaging
• Treat the underlying cause once identified
• Avoid sedation/restraints if possible until organic cause excluded; use the least restrictive means necessary for safety

Disposition

• Admit to ICU:
  • GCS ≤12, declining mental status
  • Intubated patients
  • Hemodynamic instability
  • Suspected CNS infection or stroke requiring acute intervention
• Admit to floor:
  • AMS with identified cause requiring ongoing treatment/monitoring (e.g., metabolic correction)
  • Elderly with new-onset delirium requiring workup
• Discharge:
  • Fully resolved AMS with clearly identified and treated benign cause (e.g., hypoglycemia corrected, alcohol intoxication sobered)
  • Reliable follow-up arranged
  • Safe discharge environment

See Also

• Altered mental status (peds)
• Coma
• Delirium
• Glasgow Coma Scale
• Syncope