Altered Mental Status

Cardinal Presentations

This post is part of a series called “Cardinal Presentations”, based on Rosen’s Emergency Medicine (8th edition).

Components of Consciousness

Components of Consciousness

Causes of Altered Mental Status

Causes of Altered Mental Status

History

Rate of onset
Abrupt: CNS
Gradual: Systemic

Physical Examination

  • Vital Signs

    • Blood Pressure: low (shock), high (SAH, stroke, ICP)
    • Heart Rate: low (medication overdose, conduction block), high (hypovolemia, infection, anemia, thyrotoxicosis, drug/toxin)
    • Temperature: low/high (infection, drug/toxin, environmental)
    • Respiratory Rate: low/high (CNS, drug/toxin, metabolic derangement)
  • Eyes

    • Unilateral dilation: CNS/structural cause
    • Papilledema: ICP
    • EOM: cranial nerve dysfunction
    • Oculocephalic: brainstem function
  • Head: trauma
  • Mucous membranes: hydration, laceration
  • Neck: meningeal irritation
  • Pulmonary: respiratory effort
  • CV: murmur, arrhythmia, CO
  • Abdomen: pulsatile mass, sequelae of liver failure
  • Skin: rash, needle tracks

Labs

  • Glucose
  • ECG: arrhythmia, ischemia, electrolyte abnormalities
  • BMP: electrolytes, renal failure, anion gap
  • ABG: hypoxemia, hypercarbia
  • Urinalysis: infection, SG
  • Utox
  • CBC: leukocytosis, leukopenia, severe anemia, thrombocytopenia
  • Ammonia: hepatic encephalopathy
  • TFT: thyrotoxicosis, myxedema coma
  • CSF: meningitis, encephalitis

Imaging

  • CT head: Non-contrast sufficient to identify ICH. Use contrast if mass/infection suspected
  • CTA head/neck: If aneurysm, AVM, venous sinus thrombosis or vertebrobasilar insufficiency suspected
  • CXR: PNA

References

  1. Bassin, B., & Cooke, J. (2013). Depressed Consciousness and Coma. In Rosen’s Emergency Medicine – Concepts and Clinical Practice (8th ed., Vol. 1, pp. 142-150). Elsevier Health Sciences.