Glasgow Coma Scale

Glasgow Coma Scale: level of consciousness

The Glasgow Coma Scale (GCS) rates level of consciousness from 3 to 15 by summing three components: Eye opening (1–4: 1 none, 2 to pain, 3 to voice, 4 spontaneous), Verbal response (1–5: 1 none, 2 sounds, 3 words, 4 confused, 5 oriented), Motor response (1–6: 1 none, 2 extension, 3 flexion, 4 withdrawal, 5 localizes, 6 obeys commands). Severity: 13–15 mild, 9–12 moderate, ≤8 severe (typically an indication for intubation). Example: eyes open to voice (3) + confused speech (4) + localizes pain (5) = GCS 12, moderate. The minimum possible score is 3, never 0.

Clinical context

Created by neurosurgeons Graham Teasdale and Bryan Jennett at the University of Glasgow in 1974 for traumatic brain injury (TBI). Used in emergency departments, neurosurgery, ICU, and prehospital transport (SAMU 192 in Brazil) for TBI classification and prognosis in coma. The GCS-Pupils variant subtracts 0–2 points based on pupillary reactivity for added prognostic accuracy. Pediatric and neonatal adaptations exist for non-verbal children. Always record each component separately (e.g., "E3 V4 M5 = 12") — the total alone loses information.

FAQ

Can the score be zero? No. Even a deceased or fully unresponsive patient scores 3 (1+1+1). A score below 3 is impossible.

What if the patient is intubated? Verbal response is marked "T" (tube). Record as e.g. "E2 VT M4 = 6T". Some services count V as 1 for arithmetic purposes.

Is GCS ≤8 always an indication for intubation? It is a strong indicator (airway protection), but the decision considers context: cause, trajectory, gag reflex, oxygenation.

Does GCS replace pupillary and motor exam? No. It is part of the neurological exam but must be combined with pupils, focal signs, and imaging (CT) for full assessment.