What is the Glasgow Coma Scale?

The Glasgow Coma Scale (GCS) is a scoring system used by medical practitioners to describe the level of consciousness in a person following a traumatic brain injury. It is based on a 15-point scale and is used by trained staff at the site of an injury, such as that of a vehicle crash or contact sports injury. The GCS is also used in the emergency department and intensive care units.

According to Brainline, the GCS is used to measure the severity of an acute brain injury. The test is simple, reliable, and is a good indicator of the patient’s outcome.

Glasgow Coma Scale Coding in ICD-10-CM begins once the medically trained staff has documented the scores.

man laying in bed in coma to describe Glasgow Coma Scale coding in ICD-10-CM (R40.2-)

Glasgow Coma Scale Scoring

According to the National Center for Biotechnology Information (NCBI), the Glasgow Coma Scale measures the following functions:

  • Eye-opening,
  • Verbal response, and
  • Motor response.

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 total Glasgow Coma Score has values between 3, indicating deep unconsciousness, and 15, indicating full consciousness. To determine the final score, the values from each category should be added together and may be indicated as the sum of the scores in addition to the individual elements. For example, a score of 10 might be indicated as GCS 10 = E3 V4 M3.

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 for over 5 years old showing functions being measured and their scores for eye opening response, verbal response, and motor response

Modified GCS for Children

The GCS can be used for children who are older than 5 years without any changes. Those who are younger than 5 are too young to have reliable language skills. Therefore, a modification of the CGS is used instead. It is called the Pediatric Glasgow Coma Scale (PGCS).

Children younger than 2 years of age (pre-verbal) / children older than 2 years of age (verbal)

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 (moans in response to pain)
3 = Incomprehensible words (cries in response to pain)
4 = Confused (irritable cries)
5 = Orientated (coos and babbles)

Best motor response (6)

1 = No motor response
2 = Abnormal extension to pain
3 = Abnormal flexion to pain
4 = Withdrawal to pain
5 = Localizes to pain (withdraws to touch)
6 = Obeys commands (moves spontaneously and purposefully)

Severity of Injury

Brain injuries for both adults and pediatrics are classified by severity. Although every brain injury is different, in general, brain injury is classified as:

  • Severe: GCS 8 or less
  • Moderate: GCS 9-12
  • 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.

ICD-10-CM Coding and Guidelines

When a patient is in a coma, trained medical staff should use the GCS and document the scores. Medical coders should then capture that information and assign the appropriate ICD-10-CM codes based on the coding guidelines.

Coma Scale Codes

Coma scale codes (R40.2-) 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).

R40.20, Unspecified coma

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

There is a note that indicates the appropriate 7th character should be added to subcategory R40.2- to indicate:

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

Hence, be sure to add the appropriate 7th character to each of the above-listed codes. Otherwise, the code will be invalid.

Coding Guidelines

According to the ICD-10-CM Official Guidelines for Coding and Reporting (FY 2020), coma scale codes (R40.2-) can be used along with traumatic brain injury codes, acute cerebrovascular disease, or sequelae of cerebrovascular disease codes. Coma scale codes are mainly used by trauma registries, but they may be used in other settings as well.

The coma scale may also be used to estimate the status of the central nervous system for other non-traumatic conditions, such as monitoring patients in the intensive care unit no matter the medical condition.

The diagnosis code(s) should be sequenced first, followed by the coma scale codes.

There is one code needed from each subcategory to complete the scale. The 7th character indicates when the scale was recorded, and this 7th character should be the same for all three codes.

At a minimum, the initial score documented on presentation to the facility should be reported. This may be a score from the emergency medical technician (EMT) or from the emergency department. If desired, a facility may choose to capture multiple coma scale scores.

If there is conflicting information documented, the attending provider should be queried.

When only the total score is documented in the medical record and not the individual score(s), assign code R40.24-, Glasgow coma scale, total score.

Codes for individual or total Glasgow coma scale scores should not be reported for a patient with a medically induced coma or a sedated patient.

Coding Scenario

Let’s look at the following coding scenario.

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 patient opening eyes spontaneously and obeying commands on motor response. The patient was stable and discharged home to continue recovery. 

ICD-10-CM Codes: S06.341A, R40.2131, R40.2221, R40.2331, R40.2414, Y02.0XXA

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

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

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.

Intracerebal Hemmorrage. 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.

Coma Scale Scores. According to the documentation, 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]

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]

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]

Remember our guidelines: When the individual scores are documented, they should be reported. A code from each subcategory, R40.21-R40.23, is required to complete the coma scale. The 7th character indicates when the scale was recorded, and all three codes must have the same 7th character. Also, there is a “Code first” note at R40.2 that indicates an intracranial injury (S06.-) is sequenced before the coma scale codes.

Total GCS. 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

Again, 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.

External Cause. Lastly, to our external cause code. The patient was assaulted by someone who pushed him 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. A comatose patient requires immediate medical care in order to preserve life and brain function, according to the Mayo Clinic. A coma may last several weeks. 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

Diagnosis

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:

Computerized tomography (CT) scan. X-rays are used to create an in-depth image of the brain and can show brain hemorrhage, tumors, strokes, and other conditions. This test helps in the diagnosis and cause of a coma.

Magnetic resonance imaging (MRI). Radio waves and magnets are used to create an in-depth image of the brain. It is able to detect damaged brain tissue caused by an ischemic stroke, brain hemorrhage, and other conditions. An MRI scan is particularly helpful for examining the brainstem and deep brain structures.

Electroencephalography (EEG). This measures electrical activity inside the brain. Physicians attach small electrodes to the scalp, send a low electrical current through the electrodes, and then record the brain’s electrical impulses. An EEG can detect if the cause of the coma is due to seizures.

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 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 unconscious forever. 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. Then a medical coder will need to know how to assign the appropriate GCS codes based on what has been documented. Knowing the coding guidelines, as we have discussed, will help with that. Hopefully, after reviewing the coding scenario provided, you have a better idea how to code coma scales. And as an extra, we covered what a coma is, including its symptoms, causes, diagnosis, and treatment.

 


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