2026 ICD-10-CM Diagnosis Code G09Sequelae of inflammatory diseases of central nervous system

ICD-10-CM Codes›G00–G99›G00-G09›G09

ICD-10-CM G09
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G09 is a billable ICD-10-CM diagnosis code for sequelae of inflammatory diseases of central nervous system. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Sequela of specified nervous system conditions.

Code Identity

ICD-10-CM Code
G09
Billable Status
Yes — Valid for Submission
Code Describes
Sequelae of inflammatory diseases of central nervous system
Chapter
G00-G09
Inflammatory diseases of the central nervous system

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG00-G09Inflammatory diseases of the central nervous system
CategoryG09Sequelae of inflammatory diseases of central nervous system
This CodeG09Sequelae of inflammatory diseases of central nervous system

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Hydrocephalus due to and following meningitis
  • Hydrocephalus following infectious disease
  • Late effects of intracranial abscess or pyogenic infection
  • Late effects of pyogenic intracranial abscess
  • Obstructive hydrocephalus
  • Obstructive hydrocephalus due to and following meningitis
  • Postinfectious hydrocephalus
  • Secondary tic disorder
  • Sequela of infectious meningitis
  • Sequelae of inflammatory diseases of the central nervous system
  • Sequelae of meningitis
  • Tic disorder due to post-encephalitic syndrome

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Code First

  • condition resulting from (sequela) of inflammatory diseases of central nervous system

  • Category G09 is to be used to indicate conditions whose primary classification is to G00 G08

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Abscess(connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)
      • cerebellum, cerebellar
        • sequelae
    • Abscess(connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)
      • cerebral (embolic)
        • sequelae
    • Abscess(connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)
      • extradural
        • brain
          • sequelae
    • Abscess(connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)
      • subdural
        • brain
          • sequelae
    • Parencephalitis
      • sequelae
    • Sequelae(of)
      • abscess, intracranial or intraspinal (conditions in G06)
    • Sequelae(of)
      • encephalitis or encephalomyelitis (conditions in G04)
    • Sequelae(of)
      • infection, pyogenic, intracranial or intraspinal
    • Sequelae(of)
      • meningitis
        • bacterial (conditions in G00)
    • Sequelae(of)
      • meningitis
        • other or unspecified cause (conditions in G03)
    • Sequelae(of)
      • phlebitis or thrombophlebitis of intracranial or intraspinal venous sinuses and veins (conditions in G08)
    • Suppuration, suppurative
      • brain
        • sequelae
    • Thrombophlebitis
      • cerebral (sinus) (vein)
        • sequelae
    • Thrombophlebitis
      • intracranial venous sinus (any)
        • sequelae

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NVS022
Sequela of specified nervous system conditions
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Brain Diseases

Your brain is the control center of your body. It controls your thoughts, memory, speech, and movement. It regulates the function of many organs. It's part of your nervous system, which also includes your spinal cord and peripheral nerves. The nervous system sends signals between your brain and the rest of the body.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert G09 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
326 Late eff cns abscess
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About G09Overview

Is G09 (Sequelae of inflammatory diseases of central nervous system) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report sequelae of inflammatory diseases of central nervous system on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of G09?

Under the General Equivalence Mappings, sequelae of inflammatory diseases of central nervous system converts to ICD-9-CM 326 (late eff cns abscess). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.