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ICD-10 Guide
ICD-10 CodesChapter 6: Diseases of the nervous systemG04

G04

Billable

Encephalitis, myelitis and encephalomyelitis

Chapter 6:Diseases of the nervous system

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/05/2025

Code Description

ICD-10 G04 is a billable code used to indicate a diagnosis of encephalitis, myelitis and encephalomyelitis.

Key Diagnostic Point:

Encephalitis, myelitis, and encephalomyelitis are inflammatory conditions affecting the central nervous system (CNS). Encephalitis refers to inflammation of the brain, often caused by viral infections, autoimmune responses, or bacterial infections. Myelitis involves inflammation of the spinal cord, which can lead to neurological deficits, paralysis, and sensory disturbances. Encephalomyelitis combines both brain and spinal cord inflammation, presenting a complex clinical picture. These conditions can arise from various infectious agents, including viruses (e.g., herpes simplex virus, West Nile virus), bacteria (e.g., Lyme disease), and even post-infectious autoimmune reactions. Symptoms may include fever, headache, confusion, seizures, and neurological deficits. Diagnosis typically involves clinical evaluation, imaging studies (like MRI), and laboratory tests (such as lumbar puncture for cerebrospinal fluid analysis). Prompt recognition and treatment are crucial to prevent long-term complications or mortality.

Code Complexity Analysis

Complexity Rating: High

High Complexity

Complexity Factors

  • Variety of underlying causes (viral, bacterial, autoimmune)
  • Overlap with other CNS conditions (e.g., meningitis, brain abscesses)
  • Need for precise documentation of clinical findings and diagnostic tests
  • Potential for multiple codes to be applicable based on symptoms and findings

Audit Risk Factors

  • Inadequate documentation of the specific type of encephalitis or myelitis
  • Failure to document the causative organism or underlying condition
  • Misclassification of encephalitis as meningitis
  • Lack of supporting diagnostic tests in the medical record

Specialty Focus

Medical Specialties

Neurology

Documentation Requirements

Detailed neurological examination findings, imaging results, and laboratory test results.

Common Clinical Scenarios

Patients presenting with altered mental status, seizures, or focal neurological deficits.

Billing Considerations

Ensure clarity in distinguishing between encephalitis and other CNS infections.

Infectious Disease

Documentation Requirements

Identification of infectious agents through cultures, serologies, and PCR testing.

Common Clinical Scenarios

Patients with suspected viral or bacterial CNS infections requiring specialized testing.

Billing Considerations

Document the timeline of infection and any relevant travel history.

Coding Guidelines

Inclusion Criteria

Use G04 When
  • Follow official ICD
  • CM coding guidelines, ensuring accurate coding based on the specific type of encephalitis, myelitis, or encephalomyelitis
  • Include any relevant co
  • morbidities and document the clinical rationale for the diagnosis

Exclusion Criteria

Do NOT use G04 When
No specific exclusions found.

Related CPT Codes

62270CPT Code

Lumbar puncture

Clinical Scenario

Used to obtain cerebrospinal fluid for analysis in suspected encephalitis.

Documentation Requirements

Document indication for lumbar puncture and findings from CSF analysis.

Specialty Considerations

Neurology should ensure proper technique and interpretation of results.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of encephalitis, myelitis, and encephalomyelitis, improving the accuracy of data collection and reimbursement processes. It has also facilitated better tracking of epidemiological trends in CNS infections.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of encephalitis, myelitis, and encephalomyelitis, improving the accuracy of data collection and reimbursement processes. It has also facilitated better tracking of epidemiological trends in CNS infections.

Reimbursement & Billing Impact

reimbursement processes. It has also facilitated better tracking of epidemiological trends in CNS infections.

Resources

Clinical References

  • •
    CDC - Encephalitis
  • •
    WHO - Viral Encephalitis

Coding & Billing References

  • •
    CDC - Encephalitis
  • •
    WHO - Viral Encephalitis

Frequently Asked Questions

What are the common causes of encephalitis?

Common causes include viral infections (e.g., herpes simplex virus, West Nile virus), bacterial infections, and autoimmune conditions.

How is encephalitis diagnosed?

Diagnosis typically involves clinical evaluation, imaging studies (like MRI), and lumbar puncture for cerebrospinal fluid analysis.