Coma | Medical Council of Canada
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Version: March 2023
Legacy ID: 58-1


Coma is a state of prolonged and pathologic unconsciousness. It may be defined as a score of 8 or less on the Glasgow Coma Scale. Coma is a medical emergency and requires urgent evaluation to avoid permanent brain injury or death.

Causal Conditions

(list not exhaustive)

  1. Focal disease
    1. Space-occupying lesion (e.g., tumour, abscess)
    2. Stroke (e.g., brainstem infarction)
    3. Trauma
  2. Diffuse disease
    1. Vascular (e.g., hypertensive encephalopathy, eclampsia)
    2. Infectious (e.g., meningitis, encephalitis)
    3. Metabolic (e.g., uremia, hypercalcemia, hypoglycemia)
    4. Toxins (e.g., lead, carbon monoxide, alcohol, opioids)
    5. Seizures (including postictal state)
    6. Diffuse ischemia (e.g., shock)
    7. Trauma

Key Objectives

Given a patient in coma, the candidate will diagnose the cause, severity, and complications, and will initiate an appropriate management plan.

Enabling Objectives

Given a patient in coma, the candidate will

  1. list and interpret critical clinical findings, including those derived from
    1. a complete history and corroboration of information from appropriate sources;
    2. the identification of most likely causes of coma by means of a complete physical examination including appropriate neurologic examination; and
    3. the determination of level of consciousness using an appropriate assessment tool (e.g., Glasgow Coma Scale);
  2. list and interpret critical investigations, including laboratory investigations (e.g., toxin screen, glucose), diagnostic imaging (e.g., computed tomography, magnetic resonance imaging), and others (e.g., lumbar puncture, electroencephalography); and
  3. construct an effective initial management plan, including
    1. initiating immediate and emergent care (e.g., airway, breathing, circulation) and appropriate empiric treatment as indicated (e.g., narcotic/benzodiazepine reversal, glucose);
    2. initiating other urgent treatment as indicated (e.g., antibiotics, anticonvulsants);
    3. referring the patient for specialized care (e.g., neurosurgery) if necessary; and
    4. seeking clarification of proxy decision-making while the patient is incapacitated.