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CNS, General

GCS At 40: Pediatric Glasgow Coma Scale

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I’ve been discussing the Glasgow Coma Scale (GCS), but only the adult version so far. The pediatric GCS was created about 10 years after the classic adult scale after it was recognized that several of the scores were not appropriate for younger non-verbal children, typically less than one year of age. It has been validated several times over the ensuing years and has been integrated into our trauma practices.

So what is different about the pediatric GCS scale? It has the same three main components, eye opening, best verbal response, and best motor response. The number of scores under each remains the same as well. The major changes occurred in the verbal response scores. Here’s the breakdown; I’ve highlighted the differences.

Eye Opening

  • All components are the same as for adults

Best Verbal Response

  1. No response to stimuli
  2. Inconsolable, agitated
  3. Inconsistently inconsolable, moaning
  4. Cries but consolable. Has appropriate interactions.
  5. The child smiles, orients to sounds, follows objects, and interacts with adults

Best Motor Response

  1. No response to stimuli
  2. Decerebrate posturing (extension to stimulation, see the adult post for details)
  3. Decorticate posturing (flexion to stimulation, see the adult post for details)
  4. Withdraws from pain
  5. Withdraws from touch
  6. Spontaneous, purposeful movement

In my next post in the series, I’ll review what’s new with the GCS-40 score.

Reference: Neurologic evaluation and support in the child with an acute brain insult. Pediatric Annals 15(1):16-22, 1986.

CNS

GCS At 40: The Current GCS Scale (Adult)

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My last post provided some history about the original Glasgow Coma Scale (GCS). Today, I’ll provide some of the finer details of measuring the components of the current iteration of GCS (not GCS-40). I will list out the individual scale values, and explain some of the most misunderstood.

As you know, there are three components to the GCS. Let’s examine each:

Eye Opening

  • 4 – This is an easy one. The eyes are open, and they are opened spontaneously.
  • 3 – Eyes open to your voice. If your patient is asleep and they awaken, the E score is actually 4. If they only open their eyes to repeated voice prompts, then it is a 3.
  • 2 – Eyes open only to pain or stimulation. This is typically tested by squeezing a fingernail, but the exam should progress as described in the Nuances section below.
  • 1 – This one is easy, too. The eyes don’t open, no matter what.

What if the eyes are swollen shut? Then record it as E1c (c = closed).

Verbal Response

  • 5 – Your patient is oriented and converses with you spontaneously.
  • 4 – Confused. This means that you can talk with your patient and they respond in sentences, but you can detect some confusion or disorientation based on their speech.
  • 3 – Inappropriate words. Remember it this way: your patient speaks like a 3-year-old. They can say a few words but can’t construct a meaningful sentence.
  • 2 – Incomprehensible sounds. This means that your patient may moan or make noises, but does not form any words.
  • 1 – No verbal response at all.

If the airway is controlled with an endotracheal tube, then the score is recorded as V1t.

Motor response

  • 6 – Your patient obeys commands.
  • 5 – Localizes to pain. Your patient will move toward a painful stimulus in an attempt to remove it. They can move their arms/hands above their chin in response to facial stimulation.
  • 4 – Withdrawal from pain. Patients cannot move their arms above the chin.
  • 3 – Flexor response (decorticate posturing). This score, and the next one (2), are the ones that I always confuse. Just remember that the patients reach for the “core.” They flex their forearm and wrist, clench their fist, extend their legs, and point their toes (plantar flex).

  • 2 – Extensor response (decerebrate posturing). These patients bring their arms to their sides (adduct), extend the elbow but flex the wrist and fingers, and pronate the forearms. Legs and feet are the same as above.

  • 1 – No response to stimuli.

Nuances

  • Record the entire score. This means all components and modifiers. An example would be E3 V4 M4 = 11, or E1c V1t M3 = 5, or E1 V1 M2rt M3lt = 4/5
  • Alcohol or drug intoxication will interfere with accurate measurement of the GCS, especially with the verbal and eye-opening components.
  • If the motor score is asymmetric (higher on one side than the other), record the higher score. Or better yet, break out the motor scores for both sides so your friendly, neighborhood neurosurgeon has a better idea of what is going on.
  • Stimulation should proceed from fingernail squeeze, to pinching the trapezius muscle, to pressure in the supra-orbital notch, in that order. The sternal rub is to be discouraged, as it can lead to bruising.

In my next post, I’ll describe the differences in the Pediatric Glasgow Coma Scale.

CNS

GCS At 40: The Original GCS

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The Glasgow Coma Score (GCS) has been in use for more than 40 years. Since that 40th anniversary a few years back, there has been talk of updating this tried and true system. But where did this scale come from? How was it devised? And why are we looking to update it now? I’ll dig into this topic over my next several posts.

The original paper describing the GCS was published in 1974 by Graham Teasdale and Bryan Jennett. They were neurosurgeons at the Institute of Neurologic Sciences in Glasgow, Scotland (of course) and were based in the Southern General Hospital. Until this paper was published, each report in the literature described its own assessment of level of consciousness. Most divided the spectrum into various steps noted between fully alert and comatose. Unfortunately, these systems were confusing, and they varied from 3-17 steps! There was just no consensus. Some relied on a comprehensive neurologic exam, including brainstem function tests. However, none of these were really designed for repeated bedside assessment.

Teasdale and Jennett settled on three simple areas to examine: eye-opening, motor response, and verbal response. They selected easily observable responses for each of these components. Here is a copy of the original scale:

Notice that this differs from the current-day score. The motor response did not have a “withdrawal” option, so the maximum score was only 14! But that didn’t matter much at the time; the individual components were graphed out over time for inspection. A total score was not generally calculated.

Teasdale and Jennett found that inter-rater reliability for this system was excellent, compared to a 25% discrepancy for other less objective systems in use at the time. This led to its rapid adoption over the coming years.

In my next post, I’ll describe how GCS came to be used over the ensuing years.

CNS

Could There Be A Simpler GCS?

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The Glasgow Coma Scale (GCS) has been around forever. Or really, for about 45 years. It was actually developed in the early 1970s and known as the Coma Index. It was further refined into the GCS, when 1 was selected as the minimum component score. Ever since, it has been used as a common language among clinicians to communicate gross neurologic function and trends.

But it is still somewhat complicated. Oh no it’s not, you say? Then why do so many trauma resuscitation rooms have it posted on the wall? There are three components, each with a different number of possible values. And frankly, some are harder to remember than others. Decerebrate vs decorticate, right?

So what if someone told you that a single GCS component works just about as well as the whole bunch? Researchers have been piecing this together for years, focusing on the motor component of GCS (mGCS). There are two flavors of simplified score: mGCS and Simplified Motor Score (SMS). The mGCS is just what it sounds like: the full motor component of GCS, ranging from 1-6. The SMS is further simplified from the mGCS: mGCS of 1-4 tranlsates to SMS 0, mGCS 5 = SMS 1, and mGCS 6 = SMS 2. In my opinion, this is actually more complicated because you have to remember not only the 6 mGCS levels, but also the cutoffs to convert it to SMS.

Finally, a group from Oregon Health Sciences University in Portland performed a nice meta-analysis of the best individual studies.

Here are the factoids:

  • Only papers that compared total GCS (tGCS) to mGCS or SMS were included, and only if they analyzed a receiving operator characteristic curve. The statistics appeared sound.
  • tGCS was very slightly better than either mGCS or SMS at predicting:
    • in-hospital mortality
    • neurosurgical intervention
    • emergency intubation
    • severe TBI

Bottom line: Overall, the total GCS is slightly (just a few percent) better at doing the things listed above, compared to the motor score alone or the “simplified” (really?) motor score. Is this clinically significant in the field? Probably not. And its mere simplicity makes it appealing. 

However, there is one major problem to adopting the mGCS for use outside the hospital. Inertia. As I mentioned, we have been using the full GCS score for almost 50 years. Pretty much every trauma professional is familiar with the GCS or knows where to look up the details. But I suspect that those clincicians who assume care of the patient once in the hospital, and especially the intensive care unit (neurosurgeons) will never allow the use of an abbreviated scale. Good idea, but sorry, it won’t catch on in the real world.

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Is The Glasgow Coma Scale (GCS) Getting Too Old?

Traumatic brain injury (TBI) is one of the leading causes of death from trauma worldwide. The assessment of TBI was revolutionized in 1976 when the GCS scale was first introduced. Shortly after its introduction, it was found to be predictive of outcome after brain injury. But it does have some drawbacks: it is somewhat complicated, and interrater reliability is low.

Interestingly, a number of studies have shown that the motor component of GCS is nearly as accurate as the full score in predicting survival. Thus, the Simplified Motor Score (SMS) was introduced as a possible substitute for the GCS in 2007. It was found to be equivalent for predicting survival when applied in the ED.

SMS scoring:

  • Obeys commands = 2
  • Localizes pain = 1
  • Withdraws (or less) to pain = 0

So can this scale be validated in the field when applied by prehospital providers?

Nearly 10 years of data (almost 20,000 patients) from the Denver Health trauma registry was analyzed to attempt to validate SMS when used by EMS. Although the statistics were not perfect, they found that GCS and SMS were equivalent for predicting the presence of a brain injury, need for emergency intubation, need for neurosurgical intervention, and death. Interestingly, they found that both SMS and GCS were not quite as good at predicting overall outcomes as previously thought.

Bottom line: The simplified motor score is a simple system that has now been shown to be as accurate as GCS in predicting severity and outcome from head injury. To be clear, though, neither is a perfect system. They must still be combined with clinical and radiographic assessments to achieve the best accuracy. But SMS can and should be used both in-hospital and prehospital to get a quick assessment, and may help determine early intervention and need for activating the trauma team.

References:

  • Assessment of coma and impaired consciousness: a practical scale. Lancet 2:81-84, 1976.
  • Assessment and prognosis of coma after head injury. Acta Neurochir (Wien) 34:45-55, 1976.
  • Validation of the simplified motor score in the out-of-hospital setting for the prediction of outcomes after traumatic brain injury. Ann Emerg Med, in press, Aug 2011.