2027 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 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

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 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 91 through 93. 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
Short Description
Sequelae of inflammatory diseases of central nervous system
Same as the full description in the CMS dataset.
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

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to G09: its own notes plus those printed at Chapter 6. A note printed at a category, block or chapter applies to every code under it.

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 6 (G00-G99) Diseases of the nervous system applies to 700 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Code First

The underlying condition named in the note is sequenced before this code.

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

Notes

General instructions on how these codes are used.

  • Category G09 is to be used to indicate conditions whose primary classification is to G00-G08 as the cause of sequelae, themselves classifiable elsewhere. The 'sequelae' include conditions specified as residuals.

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About G09Overview

What is the ICD-10 code for sequelae of inflammatory diseases of central nervous system?

The ICD-10-CM code for sequelae of inflammatory diseases of central nervous system is G09. It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

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, 2026 through September 30, 2027.

What MS-DRG does G09 group to?

When sequelae of inflammatory diseases of central nervous system is the principal diagnosis on an inpatient stay, it groups to MS-DRG 91, 92, 93, with relative weights from 0.7783 to 1.7050 depending on complications. Higher weights mean higher Medicare reimbursement.

What is coded first with G09?

The Code First note reads: condition resulting from (sequela) of inflammatory diseases of central nervous system. When one of these applies, it is sequenced before G09.

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.