Acute Encephalopathy and the Coma Scale

by  Cheryl Ericson, RN, MS, CCDS, CDIP
Oct 6th, 2025

This week, as we continue to explore querying for acute (metabolic or toxic) encephalopathy, I want to examine the Glasgow Coma Scale (GCS) as a clinical indicator for encephalopathy.

I know many consultants encourage this approach, but I hope to convince you that this is an outdated practice, and could contribute to clinical validation denials. As mentioned last week, there is not a widely accepted definition for metabolic or toxic encephalopathy. However, of all the definitions that I reviewed for my article, as confirmed by an artificial intelligence (AI)-driven search, I did not find any that incorporated the GCS.

Let’s begin with a discussion about the GSC. It is a universal tool used to quantify a patient’s level of consciousness on a scale from 3 to 15, wherein 15 represents normal consciousness and anything less than 8 indicates severe impairment, such as a coma or the inability to protect one’s airway. It is primarily used in patients who have suffered a traumatic brain injury. The GCS was designed to assess a patient’s level of consciousness, which is different from assessing if they are experiencing altered mental status, a component of acute encephalopathy.

The GCS is composed of three subscales: eye opening, verbal responsiveness, and motor responsiveness. A score of 13 to 15 indicates mild brain injury. Patients with a lower GCS score have an increased risk of mortality after a head injury.

• Eye opening is often the first sign of arousal. The scale includes the choices of eyes open never, to pain, to sound, or spontaneously. Most encephalopathic patients will have spontaneous eye openings or will open their eyes to sound. A lack of eye opening may occur in severe encephalopathy because it indicates coma or brainstem dysfunction, a very late sign of acute encephalopathy.

• The motor response subsection evaluates purposeful movement and brain-spinal cord integration. The scale includes choices of none (no motor response), extension, abnormal flexion, flexion withdrawal, localized pain, and obeys commands. It is the most predictive component for outcomes in patients with brain injury. Most encephalopathic patients will be able to obey commands or will exhibit spontaneous movement. Motor response, like eye opening, is an indicator of severe encephalopathy.

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This article originally published on October 6, 2025 by RACmonitor.

About Cheryl Ericson, RN, MS, CCDS, CDIP

Cheryl is the Senior Director of Clinical Policy and Education, Brundage Group. She is an experienced revenue cycle expert and is known internationally for her work as a CDI professional. Cheryl has helped establish industry guidance through contributions to ACDIS white papers and several AHIMA Practice Briefs in the areas of CDI, Denials, Quality, Querying and HIM Technology.