What does a Glasgow Coma Scale (GCS) score of 5 indicate?

Glasgow Coma Scale Score of 5: Critical Neurological Emergency

A Glasgow Coma Scale score of 5 indicates very severe traumatic brain injury with extremely high mortality risk, requiring immediate intensive care, neurosurgical consultation, and aggressive management of secondary brain injury, though prognosis remains grave with mortality rates approaching 85-100% in most studies. 1, 2

Severity Classification

• GCS 5 falls within the "very severe" traumatic brain injury category (GCS 3-5), which carries the worst prognosis among all TBI severity levels. 2 The scale ranges from 3 (deep coma/no response) to 15 (normal consciousness). 2

• In nontraumatic coma, patients with initial GCS of 3-5 had only 14.8% awake at 2 weeks, with 85.2% dead or in persistent coma. 3 This underscores the grave nature of this level of consciousness impairment.

• GCS 5 is definitively classified as coma, as coma diagnosis is only possible with GCS total scores of 3-6. 2 Scores above 6 represent other disorders of consciousness but not true coma.

Immediate Clinical Actions Required

• Any patient with GCS <14 (and certainly GCS 5) meets critical physiologic criteria requiring immediate transport to a trauma center with neurosurgical capabilities. 2, 4 This is far below the threshold for highest-level trauma activation.

• Immediate priorities include securing the airway, ensuring adequate oxygenation and ventilation, and maintaining mean arterial pressure ≥80 mmHg. 1 Hypotension and hypoxemia are independent predictors of mortality and must be aggressively corrected. 1

• Obtain immediate CT imaging to identify surgically correctable lesions (epidural hematoma, subdural hematoma, mass effect requiring decompression). 1

Essential Monitoring Requirements

• Serial GCS assessments provide substantially more valuable information than single measurements. 2, 5 For severe TBI, assess every 15 minutes for the first 2 hours, then hourly for the following 12 hours. 1, 5

• Document individual component scores (Eye-Motor-Verbal) at each assessment, not just the sum. 1, 5 The motor component has the highest predictive value in severe TBI. 4, 5

• Assess and document pupillary size and reactivity simultaneously with each GCS assessment, as these are key prognostic indicators independent of the GCS score. 1, 5

• A decrease of ≥2 points in GCS score should trigger immediate repeat CT scanning to identify evolving intracranial pathology. 1, 2

Prognostic Implications

• In pediatric post-cardiac arrest patients, GCS <5 at 24 hours after return of spontaneous circulation had 100% positive predictive value for unfavorable outcome (severe disability or death). 1 This represents one of the most robust prognostic indicators available.

• The motor component alone provides critical prognostic information: a motor score >3 on day 4 after cardiac arrest predicts favorable outcome with 84% specificity and 77% sensitivity. 5 With GCS 5, the motor score is necessarily ≤3, indicating very poor prognosis.

• Patients with GCS 3-5 are seven times less likely to awaken at 2 weeks compared to those with GCS 6-8. 3

Critical Pitfalls to Avoid

• Never rely solely on GCS score for prognostication or treatment limitation decisions. 2 Multiple confounding factors can affect GCS accuracy, including:

  • Sedation and analgesics 2, 6
  • Neuromuscular blocking agents 5, 6
  • Intubation (prevents verbal assessment) 2, 6
  • Facial trauma or periorbital swelling (prevents eye assessment) 6
  • Intoxication or metabolic derangements 2, 6
  • Hypothermia 5

• Document confounding factors explicitly when recording GCS to avoid misinterpretation. 5 For example, record as "GCS 5T" if intubated, or note "GCS 5, sedated with propofol."

• The GCS total score does not accurately reflect level of consciousness in all cases. 7 All GCS total scores between 4-14 can be associated with more than one disorder of consciousness diagnosis, with greatest variability at scores 7-11. 7

• In post-cardiac arrest patients treated with therapeutic hypothermia, GCS motor score ≤2 at day 3 is unreliable for prognostication due to drug and temperature effects. 5

Component Score Interpretation

• With GCS 5, possible component combinations are limited (e.g., E1V1M3, E2V1M2, E1V2M2). 5 Each combination provides different prognostic information:

  • Motor score of 3 (abnormal flexion/decorticate posturing) suggests cortical dysfunction with intact brainstem 5
  • Motor score of 2 (abnormal extension/decerebrate posturing) suggests deeper brainstem involvement with worse prognosis 5
  • Motor score of 1 (no response) indicates most severe injury 5

• Use central stimuli (supraorbital pressure, trapezius squeeze) to assess motor response, not peripheral stimuli, which can elicit spinal reflexes without cortical involvement. 5

Management Priorities Beyond Initial Resuscitation

• Investigate and correct all secondary brain insults: hypotension, hypoxemia, hyperthermia, hyperglycemia, hyponatremia, and elevated intracranial pressure. 1 These are modifiable factors that significantly impact outcome.

• Consider intracranial pressure monitoring in patients with severe TBI (GCS ≤8) who have abnormal CT findings or normal CT with risk factors (age >40, hypotension, or abnormal motor posturing). 1

• Maintain cerebral perfusion pressure ≥60 mmHg in adults with severe TBI. 1