Glasgow Coma Scale Coding in ICD-10-CM

Glasgow coma scale coding

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** This article was reviewed and updated on December 28, 2023. **

Glasgow Coma Scale Coding

The Glasgow Coma Scale (GCS) is a scoring system medical practitioners use to describe the level of consciousness in all types of acute medical and trauma patients. This scoring system holds great significance in emergency settings, providing critical insight into the severity of brain injuries. This article discusses the comprehensive distinctions of Glasgow Coma Scale coding in ICD-10-CM and covers the scoring and classification details, particularly pertinent to medical coders and practitioners alike. A coding example is also provided to enhance your understanding of coding for this urgent situation.

What the GCS Scoring System Measures

The GCS measures three functions: best eye response, best verbal response, and best motor response. According to StatPearls [Internet], these components are scored by levels, starting with 1 for no response, up to normal values of 4 (eye-opening response), 5 (verbal response), and 6 (motor response).

The individual components of the Glasgow Coma Scale can also be added together to provide a total Glasgow Coma Score. The total score has values between 3 and 15, with 3 being the lowest and 15 being the highest. To determine the score, add the values from the individual components and the sum of the scores. For example, a score of 10 might be expressed as GCS10 = E3V4M3. The individual components can be broken down as E3 for eye-opening to sound, V4 for a confused verbal response, and M3 for abnormal flexion to pain. Adding all three components together gives us a total score of 10.

Glasgow Coma Scale For Ages 5 and Older

The Glasgow Coma Scale is used for individuals at least 5 years of age based on the following scores:

Best eye-opening response (4)

1 = No eye opening
2 = Eye opening to pain
3 = Eye opening to sound
4 = Eyes open spontaneously

Best verbal response (5)

1 = No verbal response
2 = Incomprehensible sounds
3 = Inappropriate words
4 = Confused
5 = Orientated

Best motor response (6)

1 = No motor response
2 = Abnormal extension to pain
3 = Abnormal flexion to pain
4 = Withdrawal from pain
5 = Localizing pain
6 = Obeys commands

Glasgow coma scale coding table

Modified Glasgow Coma Scale for Children Under 5

Children younger than 5 are too young to have reliable language skills and, therefore, require a modification of the Glasgow Coma Scale called the Pediatric Glasgow Coma Scale (PGCS). Several changes have been developed over the years, but the version most often applied consists of one GCS for children under 2 years of age and one for children over 2 years old. The scores for each function are listed below.

Children younger than two years of age (pre-verbal) / Children older than two years of age (verbal)

Best Eye-opening response (4)

1 = No eye opening / 1 = No eye opening
2 = Eye opening to pain / 2 = Eye opening to pain
3 = Eye opening to sound / 3 = Eye opening to sound
4 = Eyes open spontaneously / 4 = Eyes open spontaneously

Best verbal response (5)

1 = None / 1 = None
2 = Moans in response to pain / 2 = Incomprehensible sounds
3 = Cries in response to pain / 3 = Incomprehensible words
4 = Irritable – cries / 4 = Confused
5 = Coos and babbles / 5 = Orientated – appropriate

Best motor response (6)

1 = No motor response / 1 = No motor response
2 = Abnormal extension to pain / 2 = Abnormal extension to pain
3 = Abnormal flexion to pain / 3 = Abnormal flexion to pain
4 = Withdrawal to pain / 4 = Withdrawal to pain
5 = Withdraws to pain / 5 = Localizes to pain
6 = Moves spontaneously and purposefully / 6 = Obeys commands

Severity of Brain Injury

Brain injuries for both adults and pediatrics are classified by severity. Although every brain injury is different, brain injury is generally classified as severe GCS 8 or less, moderate GCS 9-12, and mild GCS 13-15. Mild brain injuries can lead to temporary or permanent neurological symptoms. Moderate and severe brain injuries, on the other hand, often lead to continuing deterioration in cognition (thinking), physical abilities, and/or emotional/behavioral skills.

Glasgow Coma Scale Coding in ICD-10-CM

When a patient is in a coma, trained medical staff should use the Glasgow Coma Scale to assess the patient’s level of consciousness by measuring the patient’s eye opening, verbal response, and motor response. The medical coder then assigns the correct codes based on the documentation and coding guidelines.

ICD-10-CM Official Coding Guidelines

According to the ICD-10-CM Official Guidelines for Coding and Reporting (FY 2024),

  • Coma scale codes can be used in conjunction with traumatic brain injury codes and are sequenced after the diagnosis codes(s).
  • Codes R40.21- to R40.24- cannot be used with code R40.2A, Nontraumatic coma due to underlying condition. (R40.2A is a new code added for FY 2024.)
  • A coma scale code from each subcategory must be reported, with a 7th character to indicate when the score was recorded. The 7th character should match for all three codes.
  • At a minimum, report the initial score documented on presentation at your facility. This may be a score from the emergency medicine technician (EMT) or in the emergency department. If desired, a facility may choose to capture multiple coma scale scores.
  • Assign code R40.24-, Glasgow Coma Scale, total score, when only the total score is documented in the medical record and not the individual score(s).
  • If multiple coma scores are captured within the first 24 hours after hospital admission, assign only the code for the score at the time of admission. ICD-10-CM does not classify coma scores reported after admission but less than 24 hours later.
  • Coma scale scores can be documented by medical staff, such as an EMT or someone working in the emergency department. However, the physician/provider must document the underlying condition. If conflicting information is documented, the attending provider should be queried.
  • Code R40.20, Unspecified coma, should be assigned when the underlying cause of the coma is not known, or the cause is a traumatic brain injury and the coma scale is not documented in the medical record.
  • Do not report codes for unspecified coma, individual or total Glasgow coma scale scores for a patient with a medically induced coma or a sedated patient.

Coma Scale Codes

The coma scale codes (R40.21- to R40.24-) are located in Chapter 18 of the ICD-10-CM coding manual under Symptoms and signs involving cognition, perception, emotional state, and behavior (R40-R46). Their codes and their descriptions include:

R40.21-, Coma scale, eyes open

  • R40.211, Coma scale, eyes open, never
  • R40.212, Coma scale, eyes open, to pain
  • R40.213, Coma scale, eyes open, to sound
  • R40.214, Coma scale, eyes open, spontaneous

R40.22-, Coma scale, best verbal response

  • R40.221, Coma scale, best verbal response, none
  • R40.222, Coma scale, best verbal response, incomprehensible words
  • R40.223, Coma scale, best verbal response, inappropriate words
  • R40.224, Coma scale, best verbal response, confused conversation
  • R40.225, Coma scale, best verbal response, oriented

R40.23-, Coma scale, best motor response

  • R40.231, Coma scale, best motor response, none
  • R40.232, Coma scale, best motor response, extension
  • R40.233, Coma scale, best motor response, abnormal
  • R40.234, Coma scale, best motor response, flexion withdrawal
  • R40.235, Coma scale, best motor response, localizes pain
  • R40.236, Coma scale, best motor response, obeys commands

R40.24-, Coma scale, total score

  • R40.241, Glasgow coma scale score 13-15
  • R40.242, Glasgow coma scale score 9-12
  • R40.243, Glasgow coma scale score 3-8
  • R40.244, Other coma, without documented Glasgow coma scale score, or with partial score reported

The above codes require a 7th character (0, 1, 2, 3, 4) in order to be valid. The score is based on when the scale was recorded:

0 – unspecified time
1 – in the field [EMT or ambulance]
2 – at arrival to emergency department
3 – at hospital admission
4 – 24 hours or more after hospital admission

As an example, if the documentation states, “Coma scale, eye open to pain, at arrival to the emergency department,” assign R40.2122. The 7th character, “2,” should be the same for all three scores (eye-opening, verbal, and motor).

It’s important to note that coma scale codes are primarily used by trauma registries, but they may be used in any setting where this information is collected.

Glasgow Coma Scale Coding Example

Let’s look at the following coding example.

This is a 26-year-old male who was assaulted by someone pushing him in front of a motor vehicle. The patient sustained an intracerebral hemorrhage of the right cerebrum due to the assault. The EMTs state he lost consciousness for 25 minutes. Glasgow Coma Scale (GCS) scores were taken and documented by the EMTs, with response scores of eyes open: 3, verbal response: 2, and motor response: 3. The EMTs provided Immediate attention. 

Once the patient arrived at the hospital, he was treated and continued to recover. GCS on day three was 14, with the patient opening their eyes spontaneously and obeying commands on motor response. The patient was stable and discharged home to continue recovery. Assign for ICD-10-CM.

Answer: S06.341A, R40.2131, R40.2221, R40.2331, R40.2414, Y02.0XXA

ICD-10-CM codes that are used for Glasgow Coding Scale coding example

The patient’s principal diagnosis was a head injury, or intracerebral hemorrhage, in which he lost consciousness for 25 minutes.

ICD-10-CM Code for Intracerebral Hemorrhage

In ICD-10-CM, traumatic brain injuries are located in Chapter 19. Injury, poisoning, and certain other consequences of external causes (S00-T88). Intracranial injury codes are located in category S06 and are broken down into specific subcategories according to the type of traumatic injury.

To find the code for the intracerebral hemorrhage of the right cerebrum with loss of consciousness of 25 minutes, let’s look in the Alphabetic Index of ICD-10-CM under Injury, cerebral – see Injury, intracranial. Under Injury, intracranial, see intracerebral, intracerebral hemorrhage, traumatic, right side S06.34-.

In the Tabular, S06.341 can be verified as Traumatic hemorrhage of right cerebrum with loss of consciousness of 30 minutes or less.

The 6th character in codes assigned to S06.34- indicates if there was any loss of consciousness and the amount of time related to the loss of consciousness.

There is a “Use Additional” note at S06 that indicates a 7th character (A = initial encounter; B = subsequent encounter; S = Sequela) is needed to validate the code, Therefore, our correct code is:

S06.341A, Traumatic hemorrhage of right cerebrum with loss of consciousness of 30 minutes or less, initial encounter

The 7th character, “A,” is appropriate because the patient is receiving active treatment.

Per the coding guidelines, the principal diagnosis must be sequenced before coma scale codes, so S06.341A is our first code.

There is a note at S00-T88 that indicates a secondary code or codes may be needed from Chapter 20, External causes of morbidity, to indicate the cause of injury. So we will want to assign the code for the assault. We’ll come back to this after we report our secondary diagnosis codes for coma scale scores.

ICD-10-CM Codes for Coma Scale Scores

Codes for coma scale scores (R40.2-) are located in Chapter 18: Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99), specifically under Symptoms and signs involving cognition, perception, emotional state and behavior (R40-R46). These coma scale codes are used for pediatrics and adults.

The coding example states that the EMTs took and documented the Glasgow Coma Scale (GCS) scores. Based on the coding guidelines, “At a minimum, report the initial score documented on presentation at your facility. This may be a score from the emergency medical technician (EMT) or in the emergency department. If desired, a facility may choose to capture multiple coma scale scores.” The guidelines go on to state that the physician/provider must document the underlying condition, and if there is conflicting information documented, the attending provider should be queried.

Locating and Verifying Individual Coma Scale Codes:

The eyes-open response score of 3 indicates the eyes opened to sound. Looking in the Alphabetic Index, see Coma, with opening of eyes, score of, 3, R40.213. This code can then be verified in the Tabular as:

R40.2131, Coma scale, eyes open, to sound, in the field [EMT or ambulance]
Inclusion term: Coma scale eye opening score of 3

The verbal response score of 2 indicates the best verbal response was incomprehensible sounds. Looking in the Index, see Coma, with verbal response, score of, 2, R40.222. This code can then be verified in the Tabular as:

R40.2221, Coma scale, best verbal response, incomprehensible words, in the field [EMT or ambulance]
Inclusion terms: Coma scale verbal score of 2; Incomprehensible sounds (2-5 years of age); Moans/grunts to pain; restless (<2 years old)

The motor response score of 3 indicates the best motor response was abnormal flexion to pain. Looking in the Index, see Coma, with motor response, score of, 3, R40.233. This code can then be verified in the Tabular as:

R40.2331, Coma scale, best motor response, abnormal flexion, in the field [EMT or ambulance]
Inclusion terms: Abnormal flexure posturing to pain or noxious stimuli (2-5 years of age); Coma scale motor score of 3; Flexion/decorticate posturing (< 2 years of age)

As per the coding guidelines, the individual scores were documented, so they should be reported. Each code also has the same 7th character, “1” to indicate when the score was recorded. Also, there is a “Code first” note at R40.2 that indicates an intracranial injury (S06.-) is sequenced before the coma scale codes.

Locating and Verifying Total Coma Scale Code:

The total GCS score on day 3 was documented as 14. Looking in the Index, see Glasgow coma scale, total score, 13-15, R40.241. This code can then be verified in the Tabular as:

R40.2414, Glasgow coma scale score 13-15, 24 hours or more after hospital admission

The guidelines state that when only the total score is documented, and the individual scores are not, we should assign R40.24-, Glasgow coma scale, total score.

ICD-10-CM Code for External Cause

Lastly, we need to code for the external cause, which was an assault by someone who pushed the patient in front of a motor vehicle. Looking in the External Cause of Injuries Index, see Assault, pushing, before moving object, motor vehicle, Y02.0. It can then be verified in the Tabular as:

Y02.0XXA, Assault by pushing or placing victim in front of motor vehicle, initial encounter

The 7th character, “A,” indicates it is an initial encounter, and the patient is receiving active treatment.

There is a note at V00-Y99 that indicates if a code from this section is applicable, it should be assigned as a secondary code to a condition classifiable to Chapter 19, Injury, poisoning, and certain other consequences of external causes (S00-T88).

Additional Information

Since the Glasgow coma scale is used to assess patients in a coma, it’s important to understand certain facts about this serious condition. Included below are its definition, symptoms, causes, diagnosis, and treatment.

What is a Coma?

A coma is an emergency medical condition in which a person is in a state of unconsciousness and cannot move or respond to his or her environment. The Mayo Clinic reports that a comatose patient requires immediate medical care in order to preserve life and brain function. A coma may last several weeks. However, individuals who are unconscious for a longer period of time may enter a persistent vegetative state.

Coma Symptoms

Common signs and symptoms of a coma include:

  • Closed eyes
  • Depressed brainstem reflexes, such as pupils not responding to light
  • No responses of limbs, except for reflex movements
  • No response to painful stimuli, except for reflex movements
  • Irregular breathing

Causes

A coma may be due to:

  • Traumatic head injury
  • Stroke
  • Brain tumor
  • Ongoing seizures
  • Exposure to toxins
  • Lack of oxygen
  • Underlying conditions, such as an infection or diabetes
  • Drug or alcohol intoxication

Diagnosing a Coma

Since coma patients cannot communicate, the physician will need to rely on information from others. Information of interest includes the events leading up to the coma, how the person lost consciousness, any signs or symptoms prior to the loss of consciousness, the person’s medical history, recent changes in the person’s behavior, and the person’s drug use.

Physical Examination

During a physical examination, a physician will:

  • Look for movements and reflexes, response to painful stimuli, and pupil size
  • Examine breathing patterns to help determine the cause of the coma
  • Examine skin for bruises caused by possible trauma
  • Talk loudly or press on the jaw or nail bed to determine the level of consciousness
  • Look for any signs of awakening, such as vocal sounds, eyes opening, or movement
  • Test the eye movements for reflex to determine the cause of coma and area of brain damage
  • Squirt cold or warm water into the ear canals to see any visual reactions

Laboratory Tests and Brain Scans

Blood tests and brain scans are generally ordered to determine the cause of the coma and start the appropriate treatment.

A physician will take blood samples to check for:

  • Complete blood count
  • Electrolytes, glucose, thyroid, kidney, and liver function
  • Carbon monoxide poisoning
  • Drug or alcohol overdose

A spinal tap (lumbar puncture) will determine if there are any signs of infection in the nervous system. During this procedure, a needle is inserted into the spinal canal, and a small amount of fluid is collected for analysis.

Imaging tests help the physician determine the areas of brain injury. These tests include a computerized tomography (CT) scan, a magnetic resonance imaging (MRI), and an electroencephalography (EEG).

Treatment

A coma requires immediate medical care. Although treatment is based on the cause, physicians will first check the patient’s airway and help manage respiration (breathing) and circulation. Physicians may also provide breathing assistance, blood transfusions, and other needed care. Before blood test results return, emergency staff may administer intravenous glucose or antibiotics. This is done in case of diabetic shock or an infection involving the brain. In order to relieve pressure on the brain caused by brain swelling, medications or a procedure may need to be provided.

If the cause of the coma is a drug overdose, physicians may provide medications to treat the condition. If, on the other hand, the cause of the coma is due to seizures, medication will be given to control the seizures. Medications or therapies to control diabetes, liver disease, or other underlying disease may be treated with medications or therapies.

The cause of a coma can sometimes be reversed, and the patient may regain normal function. However, if the patient suffers serious brain damage, he or she may experience permanent disabilities or may remain indefinitely unconscious. The patient may also enter an endless vegetative state or lose complete brain function.

Conclusion

When a patient suffers a traumatic brain injury, a trained professional will use the Glasgow coma scale to measure his or her brain function to classify the severity of the brain injury. Then a medical coder will need to know how to assign the appropriate GCS codes based on what has been documented and in accordance with the coding guidelines. This article illuminates this information and provides a comprehensive coding example to equip medical coders with the knowledge necessary to accurately report these codes. Besides coding, critical information about coma, including its symptoms, causes, diagnosis, and treatment, gives a more detailed picture of patient care in the face of traumatic brain injuries.

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