Skip Navigation LinksHome > June 2012 - Volume 18 - Issue 3, Critical Care Neurology > Coding Issues in Critical Care Patients With an Emphasis on...
CONTINUUM: Lifelong Learning in Neurology:
doi: 10.1212/01.CON.0000415435.73845.9b
Practice Issues

Coding Issues in Critical Care Patients With an Emphasis on Encephalopathy

Powers, Laura B. MD, FAAN

Free Access
Article Outline
Collapse Box

Author Information

Address correspondence to AAN Medical Economics and Management Committee, c/o Luana Ciccarelli, Medical Economics Administrator, American Academy of Neurology, 201 Chicago Avenue South, Minneapolis, MN 55416, lciccarelli@aan.com.

Relationship Disclosure: Dr Powers serves as ICD-9-CM advisor for the Coding Subcommittee of the AAN Medical Economics and Management Committee and serves in an editorial capacity for Neurology: Clinical Practice.

Unlabeled Use of Products/Investigational Use Disclosure: Dr Powers reports no disclosure.

Accurate coding is an important function of neurologic practice. This section of CONTINUUM, contributed by members of the AAN Medical Economics and Management Committee, includes helpful coding information and examples related to the issue topic. This section may include diagnosis coding, evaluation and management coding, procedure coding, or a combination, depending on which is most useful for the subject area of the issue.

Evaluation and management of the critically ill patient is both difficult and time consuming. Current Procedural Terminology (CPT) recognizes this with the Critical Care codes.1 A prior issue of CONTINUUM discussed the use of these Evaluation and Management (E/M) codes.2 Remember that the Critical Care codes may be used only for care given for the critical illness and not for conditions that are associated but not critical. They may not be used after the critical phase of the illness has passed (even if the patient remains in the intensive care unit). Recording the time spent with the patient is absolutely essential for using these codes. When Critical Care codes are not appropriate, use the other CPT E/M codes, including Prolonged Service codes when their requirements are met. Also remember that the brain death evaluation is bundled into the E/M codes.

Back to Top | Article Outline

CPT PROCEDURE CODING

As evidenced by the articles in this issue of CONTINUUM, neurointensivists are trained to perform procedures traditionally done by other specialists in the past. Some payers, such as Medicare, might not automatically question the use of these procedure codes by neurologists for Part B claims. Other payers may restrict the use of these codes to specific specialties, such as limiting the use of ventriculostomy codes to neurosurgeons.

Critical care neurologists must be credentialed within their individual institution(s) before performing and billing for these procedures. State laws may also limit the specialties permitted to perform some procedures.

Back to Top | Article Outline

DIAGNOSIS CODING

Diagnosis codes for traumatic brain injury, cerebrovascular disease, and neurologic complications of systemic disease were discussed in prior issues of CONTINUUM.3–5 This discussion will be limited to coding for encephalopathies.

The four general International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes for encephalopathy are:

348.30 Encephalopathy, unspecified

348.31 Metabolic encephalopathy

 Septic encephalopathy

Excludes: toxic metabolic encephalopathy (349.82)

348.39 Other encephalopathy

Excludes: encephalopathy:

  alcoholic (291.2)

  hepatic (572.2)

  hypertensive (437.2)

  toxic (349.82)

349.82 Toxic encephalopathy

 Toxic metabolic encephalopathy

 Use additional E code to identify cause.

Note that in ICD-9-CM, the word “toxic” means an adverse effect of a foreign substance. Therefore, it is best never to use the term “toxic metabolic encephalopathy” interchangeably with “metabolic encephalopathy.”

International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes are expected to become mandatory in the next few years, with the final implementation date currently under reconsideration. ICD-10-CM general encephalopathy codes are:

G92 Toxic encephalopathy

  Toxic encephalitis

  Toxic metabolic encephalopathy

 Code first (T51 to T65) to identify toxic agent.

G93.40 Encephalopathy, unspecified

G93.41 Metabolic encephalopathy

 Septic encephalopathy

G93.49 Other encephalopathy

 Encephalopathy not elsewhere classified

G94 Other disorders of brain in diseases classified elsewhere

 Code first underlying disease.

Following are discussions of more specific encephalopathy codes.

Back to Top | Article Outline
Anoxic-Ischemic Encephalopathy

In the neurologic assessment after cardiac arrest, a common neurologic diagnosis is anoxic encephalopathy or hypoxic-ischemic encephalopathy (HIE). Finding the ICD-9-CM code for HIE is a little tricky. The index entry refers HIE to a set of neonatal codes (768.0 to 768.3). These codes may not be used in adults. The appropriate non-neonatal code is:

348.1 Anoxic brain damage

The ICD-10-CM code for non-neonatal HIE after cardiac arrest would be:

G93.1 Anoxic brain damage, not elsewhere classified

Back to Top | Article Outline
Hepatic Encephalopathy

There are specific codes in the ICD-9-CM and the ICD-10-CM for hepatic encephalopathy. The ICD-9-CM code does not distinguish between mild encephalopathy and coma:

572.2 Hepatic encephalopathy

 Hepatic coma

 Hepatocerebral intoxication

 Portal-systemic encephalopathy

Excludes: hepatic coma associated with viral hepatitis – see category 070

Note: In the case of viral hepatitis, use the specific viral hepatitis code, which includes a fourth digit that indicates whether hepatic coma is present.

The ICD-10-CM does not specify one code for hepatic encephalopathy. Instead, the presence of “coma” or encephalopathy is captured in coding for the specific hepatic disorder as:

K70.41 Alcoholic hepatic failure with coma

K71.11 Toxic liver disease with hepatic necrosis, with coma

K72.01 Acute and subacute hepatic failure with coma

K72.11 Chronic hepatic failure with coma

K72.91 Hepatic failure, unspecified with coma

 Hepatic coma not otherwise specified

Note: K72.91 is the “default” code for hepatic encephalopathy when the type of liver disease is not given.

Back to Top | Article Outline
Encephalopathy in Renal Disease

The ICD-9-CM does not specify a code associated with uremic encephalopathy, so a combination of codes for encephalopathy and the renal condition should be used. Coding for renal conditions is complicated and is addressed in a prior CONTINUUM issue.5 These codes capture stages of chronic kidney disease and also change if the renal disease is due to diabetes or hypertension. Using the simple example of metabolic encephalopathy associated with acute renal failure due to acute tubular necrosis, the associated ICD-9-CM codes are:

348.31 Metabolic encephalopathy

584.5 Acute kidney failure with lesion of tubular necrosis

In the ICD-10-CM:

G93.41 Metabolic encephalopathy

N17.0 Acute kidney failure with tubular necrosis

Dialysis disequilibrium syndrome is coded to 276.9, electrolyte and fluid disorders not elsewhere classified, and therefore does not describe the symptoms. To capture the associated encephalopathy, it is best to document the term and then also use an encephalopathy code.

Document: “encephalopathy associated with dialysis disequilibrium”

In the ICD-9-CM:

Dialysis dementia has yet another set of codes specifically directed by the index of the ICD-9-CM:

348.31 Metabolic encephalopathy

276.9 Electrolyte and fluid disorders not elsewhere classified

In the ICD-10-CM:

G93.41 Metabolic encephalopathy

E87.8 Other disorders of electrolyte and fluid balance, not elsewhere classified

Dialysis dementia has yet another set of codes specifically directed by the index of the ICD-9-CM:

If persistent: 294.8 Other persistent mental disorders due to conditions classified elsewhere

If transient: 293.9 Unspecified transient mental disorder in conditions classified elsewhere

In the ICD-10-CM, there is only one appropriate code for 294.8 and 293.9, but this code has a “code first instruction” that indicates another code should be listed first:

T88.8XXA* Other specified complications of surgical and medical care, not elsewhere classified

F06.8 Other specified mental disorders due to known physiologic condition

*Note that the seventh character “A” denotes this is an initial visit. Subsequent visits would use the character “D,” and a visit for sequelae of the disease would use the seventh character “S.”

Back to Top | Article Outline
Sepsis-Associated Encephalopathy

Sepsis-associated encephalopathy is specifically included within the code for metabolic encephalopathy (384.31 in the ICD-9-CM and G93.41 in the ICD-10-CM).

Back to Top | Article Outline
Toxic and Drug-Induced Encephalopathy

For each drug or other toxin, refer to the Table of Drugs and Chemicals in the ICD-9-CM and the ICD-10-CM. A code from those tables should be used to describe the situation for that substance for each patient: poisoning, accidental, therapeutic use, suicide attempt, assault, or undetermined. Note that the code from this table is listed second in the ICD-9-CM and first in the ICD-10-CM.

For instance, codes for a patient with encephalopathy due to environmental arsenic poisoning would be:

In the ICD-9-CM:

349.82 Toxic encephalopathy

985.1 Toxic effect of arsenic and its compounds

In the ICD-10-CM:

T57.0X1A* Toxic effect of arsenic and its compounds, accidental (unintentional)

G92 Toxic encephalopathy

*Note that the seventh character “A” denotes this is an initial visit. Subsequent visits would use the character “D,” and a visit for sequelae of the disease would use the seventh character “S.”

If a patient has encephalopathy due to therapeutic doses of tricyclic antidepressants, the codes are:

In the ICD-9-CM:

349.82 Toxic encephalopathy

E939.0 Drugs, medicinal and biological substances causing adverse effects in therapeutic use, antidepressants

In the ICD-10-CM:

T43.015A* Adverse effect of tricyclic antidepressants

G92 Toxic encephalopathy

*Note that the seventh character “A” denotes this is an initial visit. Subsequent visits would use the character “D,” and a visit for sequelae of the disease would use the seventh character “S.”

Lead encephalopathy has its own set of codes in the ICD-9-CM because it (along with carbon tetrachloride, hydroxyquinoline derivatives, mercury, and thallium) is considered by the ICD-9-CM to be a toxic encephalitis, myelitis, and/or encephalomyelitis. The first code depends on the circumstance of the toxicity, with code choices listed in the Table of Drugs and Chemicals. The coding difference is not reflected in the ICD-10-CM. For environmental lead poisoning and encephalopathy, the codes are:

In the ICD-9-CM:

984.9 Toxic effect of unspecified lead compound

323.71 Toxic encephalitis and encephalomyelitis

In the ICD-10-CM:

T56.0X1A* Toxic effect of lead and its compounds, accidental (unintentional)

G92 Toxic encephalopathy

 Toxic encephalitis

 Toxic metabolic encephalopathy

*Note that the seventh character “A” denotes this is an initial visit. Subsequent visits would use the character “D,” and a visit for sequelae of the disease would use the seventh character “S.”

Back to Top | Article Outline
Encephalopathy with Endocrine Disorders

Note that in the ICD-9-CM and the ICD-10-CM the codes for thyrotoxicosis require a fifth digit describing whether thyrotoxic crisis or storm is mentioned. It would be important to document this in the case of encephalopathy associated with hyperthyroidism. For encephalopathy in both hyperthyroidism and hypothyroidism, add the manifestation code 348.39 (ICD-9-CM) or G93.49 (ICD-10-CM) to the thyroid condition code for clarity.

Back to Top | Article Outline
Encephalopathy in Disorders of Glucose Metabolism

In the ICD-9-CM and the ICD-10-CM, encephalopathy and coma are considered separate complications for hypoglycemia (indexed separately). This is not as clear for hyperosmolarity and diabetic ketoacidosis. To capture the best information, use the “coma” codes for both here.

If the encephalopathy is due to diabetes-associated hyperglycemia or hypoglycemia, the code choice depends on the type of diabetes, the control, and the manifestation. The fifth digit for all diabetes codes is for the type and control of diabetes:

Fifth Digit Descriptor

0 Type II or unspecified type, not stated as uncontrolled (even if the patient requires insulin)

1 Type I [juvenile type], not stated as uncontrolled

2 Type II or unspecified type, uncontrolled

3 Type I [juvenile type], uncontrolled

There are separate codes for primary and secondary diabetes (“x” represents the fifth digit):

Condition   Primary Diabetes   Secondary Diabetes

Hypoglycemic encephalopathy in diabetes   250.6x Diabetes with neurological manifestations   249.6x Secondary diabetes with neurological manifestations

  348.31 Metabolic encephalopathy   348.31 Metabolic encephalopathy

Hypoglycemic coma in diabetes   250.3x Diabetes with other coma   249.3x Secondary diabetes mellitus with other coma

Nonketotic hyperglycemic coma   250.2x Diabetes with hyperosmolarity   249.2x Secondary diabetes mellitus with hyperosmolarity

Encephalopathy with diabetic ketoacidosis   250.3x Diabetes with other coma   249.3x Secondary diabetes mellitus with other coma

Nondiabetic hypoglycemic coma is coded as 251.2, hypoglycemia, unspecified, to which an encephalopathy code would be added.

In the ICD-10-CM, diabetes codes include all of the information in one code as in the table below:

E08.01 Diabetes mellitus due to underlying condition with hyperosmolarity with coma

 Code first underlying condition.

E08.11 Diabetes mellitus due to underlying condition with ketoacidosis with coma

 Code first underlying condition.

E08.641 Diabetes mellitus due to underlying condition with hypoglycemia with coma

 Code first underlying condition.

E09.01 Drug or chemical induced diabetes mellitus with hyperosmolarity with coma

 Code first poisoning due to drug or toxin if applicable (T36 to T65) with fifth or sixth character 1 to 4 or 6. Use additional code for adverse effect, if applicable, to identify drug (T36 to T50) with fifth or sixth character 1 to 4 or 6.

This means that the diabetes code is listed second in the case of poisoning but first in the case of adverse effect.

E09.11 Drug or chemical induced diabetes mellitus with ketoacidosis with coma

 Code first poisoning due to drug or toxin if applicable (T36 to T65) with fifth or sixth character 1 to 4 or 6. Use additional code for adverse effect, if applicable, to identify drug (T36 to T50) with fifth or sixth character 1 to 4 or 6.

E09.641 Drug or chemical induced diabetes mellitus with hypoglycemia with coma

 Code first poisoning due to drug or toxin if applicable (T36 to T65) with fifth or sixth character 1 to 4 or 6. Use additional code for adverse effect, if applicable, to identify drug (T36 to T50) with fifth or sixth character 1 to 4 or 6.

E10.11 Type 1 diabetes mellitus with ketoacidosis with coma

E10.641 Type 1 diabetes mellitus with hypoglycemia with coma

E11.01 Type 2 diabetes mellitus with hyperosmolarity with coma

E11.641 Type 2 diabetes mellitus with hypoglycemia with coma

E13.01 Other specified diabetes mellitus with hyperosmolarity with coma

E13.11 Other specified diabetes mellitus with ketoacidosis with coma

E13.641 Other specified diabetes mellitus with hypoglycemia with coma

E15 Nondiabetic hypoglycemic coma

E16.0 Drug-induced hypoglycemia with coma.

 Use additional code for adverse effect, if applicable, to identify drug (T36 to T50) with fith or sixth character 1 to 4 or 6.

E16.2 Hypoglycemia, unspecified.

Note that nondiabetic hypoglycemic encephalopathy is indexed to this code. Use G93.41 first to capture encephalopathy.

Back to Top | Article Outline
Other Encephalopathy Codes

Following is a list of codes for several other encephalopathies mentioned in this issue. Two codes are required if the classification does not index the encephalopathy directly to the condition as it does for Wernicke encephalopathy. If the first code is one of those listed above, the descriptor is not given.

ICD-9-CM codes:

Encephalopathy Cause   First Code   Second Code

Hyponatremia   348.31   276.1 Hyposmolality and/or hyponatremia

Hypernatremia   348.31   276.0 Hyperosmolality and/or hypernatremia

Wernicke encephalopathy   265.1 Other and unspecified manifestations of thiamine deficiency

Vitamin B12 deficiency without anemia   348.39   266.2 Other B-complex deficiencies

Niacin deficiency (pellagra)   348.3   265.2 Pellagra

Hypertensive encephalopathy   437.2 Hypertensive encephalopathy

Posterior reversible encephalopathy syndrome   348.39

ICD-10-CM codes:

Encephalopathy Cause   First Code   Second Code

Hyponatremia   G93.41   E87.1 Hypo-osmolality and hyponatremia

Hypernatremia   G93.41   E87.0 Hyperosmolality and hypernatremia

Wernicke encephalopathy   E51.2 Wernicke’s encephalopathy

Vitamin B12 deficiency without anemia   G93.49   E53.8 Deficiency of other specified B group vitamins

Niacin deficiency (pellagra)   E52 Niacin deficiency [pellagra]   G32.89 Other specified degenerative disorders of nervous system in diseases classified elsewhere

Hypertensive encephalopathy   I67.4 Hypertensive encephalopathy

Posterior reversible encephalopathy syndrome   I67.83 Posterior reversible encephalopathy syndrome

Back to Top | Article Outline

REFERENCES

1. American Medical Association. CPT current procedural terminology 2012. Chicago, IL: American Medical Association Press, 2011.

2. Powers LB. Coding issues: current procedural terminology evaluation and management coding for neurologic consultations. Continuum Lifelong Learning Neurol 2011; 17 (5): 1129–1134.

3. Powers LB, Nuwer MR. Coding table. Continuum Lifelong Learning Neurol 2010; 16 (6): 171–178.

4. Powers LB. Coding issues: coding for stroke prevention. Continuum Lifelong Learning Neurol 2011; 17 (6): 1344–1348.

5. Powers LB. Coding table. Continuum Lifelong Learning Neurol 2011; 17 (1): 159–168.

© 2012 American Academy of Neurology

Login