What it is
The Glasgow Coma Scale (GCS) is a structured, reproducible measure of impaired consciousness built from three independently scored domains — eye opening (E, 1–4), verbal response (V, 1–5), and motor response (M, 6–1). The sum ranges 3 (deep coma) to 15 (fully alert). It standardises serial neuro assessment and triages traumatic brain injury severity.
Method
Score each domain on the patient’s best response and report as a triad plus total, e.g. E3 V4 M5 = 12. Always document the components, not just the sum — an isolated total hides clinically important patterns (a low motor with intact eyes differs from the reverse).
Severity bands by total:
- 13–15 — mild
- 9–12 — moderate
- ≤8 — severe (the airway-protection threshold; consider intubation)
Pediatric and infant modifications
The adult verbal and motor scales assume a cooperative, verbal patient, so the Pediatric GCS substitutes age-appropriate responses for pre-verbal children while keeping the same 3–15 range and severity cutoffs:
Verbal (infant): coos/babbles = 5; irritable cry = 4; cries to pain = 3; moans to pain = 2; none = 1.
Motor (infant): spontaneous purposeful movement = 6; withdraws to touch = 5; withdraws to pain = 4; abnormal flexion = 3; extension = 2; none = 1.
Eye opening is unchanged (spontaneous 4, to sound 3, to pressure 2, none 1). In the intubated, sedated, or pre-verbal child the verbal score is unobtainable — annotate the V as “T” (tube) and weight the motor response, which is the strongest single predictor of outcome.
When to use
Acute head injury, altered mental status, post-ictal states, toxic/metabolic encephalopathy, and any setting needing reproducible serial tracking of consciousness. A falling GCS — especially a dropping motor score — signals deterioration and prompts re-imaging or airway escalation.
Worked example
A 9-month-old after a fall: opens eyes to voice (E3), irritable cry that is not consolable (V4 on the infant scale), withdraws the limb to touch (M5). GCS = 3 + 4 + 5 = 12/15 — moderate. Document the triad and re-score at fixed intervals; a drop to ≤8 mandates urgent airway and neurosurgical attention.
Pitfalls
- Don’t average or guess across domains — use the best response in each and record the triad.
- Apply the infant scale to pre-verbal children; the calculator here uses adult verbal/motor wording, so map infant responses onto the equivalent point values above.
- Sedation, paralysis, intubation, hypoglycemia, hypoxia, hypothermia, and intoxication all depress GCS independent of brain injury — correct and reassess before attributing a low score to structural pathology.
- The ≤8 = intubate heuristic is a prompt, not a mandate; trajectory and the ability to protect the airway matter more than a single number.
- Inter-rater variability is real — the structured Glasgow approach (assess each criterion in order) reduces it.
Run it: Glasgow Coma Scale (GCS)
Decision support for qualified clinicians only — verify against current primary guidelines and your clinical judgement.