G00-G09
Medium Complexity

Inflammatory diseases of the central nervous system

Primary Specialty: Neurology
Last Updated: 2025-09-10

ICD-10 Codes (37)

37 billable
0 category headers
G01
Billable
Meningitis in bacterial diseases classified elsewhere
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G02
Billable
Meningitis in other infectious and parasitic diseases classified elsewhere
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G03
Billable
Meningitis due to other and unspecified causes
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G03.0
Billable
Nonpyogenic meningitis
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G03.1
Billable
Chronic meningitis
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G03.2
Billable
Benign recurrent meningitis [Mollaret]
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G03.8
Billable
Meningitis due to other specified causes
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G03.9
Billable
Meningitis, unspecified
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G04
Billable
Encephalitis, myelitis and encephalomyelitis
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G04.0
Billable
Acute disseminated encephalitis and encephalomyelitis (ADEM)
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G04.00
Billable
Acute disseminated encephalitis and encephalomyelitis, unspecified
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G04.01
Billable
Postinfectious acute disseminated encephalitis and encephalomyelitis (postinfectious ADEM)
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G04.02
Billable
Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis
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G04.1
Billable
Tropical spastic paraplegia
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G04.2
Billable
Bacterial meningoencephalitis and meningomyelitis, not elsewhere classified
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G04.3
Billable
Acute necrotizing hemorrhagic encephalopathy
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G04.30
Billable
Acute necrotizing hemorrhagic encephalopathy, unspecified
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G04.31
Billable
Postinfectious acute necrotizing hemorrhagic encephalopathy
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G04.32
Billable
Postimmunization acute necrotizing hemorrhagic encephalopathy
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G04.39
Billable
Other acute necrotizing hemorrhagic encephalopathy
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G04.8
Billable
Other encephalitis, myelitis and encephalomyelitis
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G04.81
Billable
Other encephalitis and encephalomyelitis
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G04.82
Billable
Acute flaccid myelitis
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G04.89
Billable
Other myelitis
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G04.9
Billable
Encephalitis, myelitis and encephalomyelitis, unspecified
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G04.90
Billable
Encephalitis and encephalomyelitis, unspecified
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G04.91
Billable
Myelitis, unspecified
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G05
Billable
Encephalitis, myelitis and encephalomyelitis in diseases classified elsewhere
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G05.3
Billable
Encephalitis and encephalomyelitis in diseases classified elsewhere
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G05.4
Billable
Myelitis in diseases classified elsewhere
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G06
Billable
Intracranial and intraspinal abscess and granuloma
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G06.0
Billable
Intracranial abscess and granuloma
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G06.1
Billable
Intraspinal abscess and granuloma
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G06.2
Billable
Extradural and subdural abscess, unspecified
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G07
Billable
Intracranial and intraspinal abscess and granuloma in diseases classified elsewhere
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G08
Billable
Intracranial and intraspinal phlebitis and thrombophlebitis
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G09
Billable
Sequelae of inflammatory diseases of central nervous system
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Updates & Changes

FY 2026 Updates

Current Year

Deleted Codes

No codes deleted in this range for FY 2026

No significant changes for FY 2026

This range maintains stability with current coding practices

Historical Changes

  • FY 2025: Routine maintenance updates with minor terminology clarifications
  • FY 2024: Enhanced specificity requirements for certain code ranges
  • FY 2023: Updated documentation guidelines for improved clarity

Upcoming Changes

  • Proposed updates pending review by Coordination and Maintenance Committee
  • Under consideration: Enhanced digital health integration codes

Implementation Guidance

  • Review all FY 2026 updates for G00-G09 codes before implementation
  • Always verify the most current codes in the ICD-10-CM manual
  • Ensure clinical documentation supports the selected diagnosis codes
  • +3 more guidance items...

Range Overview

high priority

The ICD-10 code range G00-G09 covers inflammatory diseases of the central nervous system, including bacterial meningitis, nonpyogenic meningitis, encephalitis, and other inflammatory conditions. These codes are used to document various types of inflammation that affect the brain and spinal cord, providing a detailed picture of the patient's condition for accurate diagnosis, treatment, and billing.

Key Usage Points:

  • Always code to the highest level of specificity, using additional codes if necessary to describe the patient's condition fully.
  • Use combination codes to document both the disease and its manifestations.
  • Remember to code first any associated underlying condition.
  • For recurrent conditions, use the appropriate code to indicate the frequency of episodes.
  • When coding for postprocedural meningitis, use an additional code to identify the procedure.

Coding Guidelines

When to Use:

  • When a patient presents with symptoms of meningitis and the physician confirms a diagnosis of bacterial meningitis.
  • When a patient has been diagnosed with encephalitis due to a specific virus.
  • When a patient has a chronic inflammatory disease of the central nervous system, such as multiple sclerosis.
  • When a patient has postprocedural meningitis.
  • When a patient has a recurrent condition, such as recurrent meningitis.

When NOT to Use:

  • When the inflammation is not located in the central nervous system.
  • When the condition is not inflammatory in nature.
  • When the patient's condition is still under investigation and no definitive diagnosis has been made.
  • When the patient's condition is a direct result of trauma, not an inflammatory process.
  • When the patient's condition is due to a congenital anomaly.

Code Exclusions

Always verify exclusions against the patient's medical record and the latest ICD-10 guidelines.

Documentation Requirements

Documentation for codes in the G00-G09 range should include a clear and specific diagnosis, the cause of the condition (if known), the location of the inflammation, and any associated conditions or complications. The patient's medical history, clinical findings, and treatment plan should also be documented.

Clinical Information:

  • Specific diagnosis
  • Cause of the condition
  • Location of the inflammation
  • Associated conditions or complications
  • Patient's medical history and clinical findings

Supporting Evidence:

  • Lab results confirming the diagnosis
  • Imaging studies showing the location and extent of the inflammation
  • Physician's notes on the patient's symptoms and response to treatment
  • Consultation reports from specialists
Good Documentation Example:

Patient presented with severe headache, fever, and stiff neck. Lumbar puncture confirmed bacterial meningitis. Patient was admitted for intravenous antibiotics.

Poor Documentation Example:

Patient has meningitis.

Common Documentation Errors:

  • Not documenting the specific type of meningitis or encephalitis
  • Not documenting the cause of the condition
  • Not documenting associated conditions or complications
  • Not providing supporting evidence for the diagnosis

Range Statistics

10
Total Codes
37
Billable
Complexity:
Medium
Primary Use:Clinical Documentation
Chapter:6

Coding Complexity

Medium
Complexity Rating

Coding for inflammatory diseases of the CNS can be complex due to the need for high specificity, the use of combination codes, and the need to code underlying conditions first. However, with careful attention to the patient's medical record and the latest ICD-10 guidelines, accurate coding is achievable.

Key Factors:
  • The need to code to the highest level of specificity
  • The use of combination codes to document both the disease and its manifestations
  • The need to code first any associated underlying condition
  • The need to indicate the frequency of episodes for recurrent conditions
  • The need to use an additional code for postprocedural meningitis

Specialty Focus

Codes in the G00-G09 range are primarily used by neurologists, infectious disease specialists, and hospitalists. They are also used by other specialists and general practitioners when treating patients with these conditions.

Primary Specialties:
Neurology
60%
Infectious Disease
30%
Hospital Medicine
10%
Clinical Scenarios:
  • A patient with HIV presents with headache and fever. Lumbar puncture confirms cryptococcal meningitis.
  • A patient with a history of recurrent bacterial meningitis presents with symptoms of another episode.
  • A patient develops meningitis after undergoing brain surgery.
  • A patient presents with symptoms of encephalitis. Lab tests confirm herpes simplex virus as the cause.
  • A patient with multiple sclerosis has a flare-up of symptoms.

Resources & References

Resources for coding inflammatory diseases of the CNS include the official ICD-10 guidelines, clinical reference books and websites, and educational materials from professional coding organizations.

Official Guidelines:

  • ICD-10-CM Official Guidelines for Coding and Reporting
  • World Health Organization's ICD-10 Browser
  • Centers for Disease Control and Prevention's ICD-10 resources

Clinical References:

  • Harrison's Principles of Internal Medicine
  • UpToDate clinical resource website

Educational Materials:

  • American Health Information Management Association's coding resources
  • American Academy of Professional Coders' training materials

Frequently Asked Questions

Can I use a G00-G09 code if the patient's condition is suspected but not confirmed?

No, these codes should only be used when the diagnosis has been confirmed by the physician. If the condition is suspected but not confirmed, use a code for the patient's presenting symptoms instead.