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G09 ICD-10-CM Code: Sequelae of inflammatory diseases of central nervous system

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
1 code-first instruction

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v44, Appendix B.

  • MS-DRG 091 — OTHER DISORDERS OF NERVOUS SYSTEM WITH MCC (MDC 01)
  • MS-DRG 092 — OTHER DISORDERS OF NERVOUS SYSTEM WITH CC (MDC 01)
  • MS-DRG 093 — OTHER DISORDERS OF NERVOUS SYSTEM WITHOUT CC/MCC (MDC 01)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for G09 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2027Effective: October 1, 2026

Trace:FY2027 changesChange historyRelease, file and checksum

Code First

Underlying conditions that must be sequenced before this code.

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

Coder workflow for G09

MedCoder structured workflow — derived from this code’s own official record

Choose the right path

  1. Is the underlying (etiologic) condition the Code First note names documented?
    Yes → Sequence the underlying condition first, then G09.
    No → Continue; do not add an underlying condition the record does not document.

Consider G09. Then confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).
The underlying (etiologic) condition
Named in the Code First note; sequenced before this code when documented (Guidelines I.A.13).

Official instructions as workflow

  • Code First — sequencing check(1 note)

    Coding workflow: Check whether the underlying or etiologic condition the note names is documented. When it is, sequence it before G09. Do not add an underlying condition the record does not document.

    See the official tabular notes · Guidelines I.A.13

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: The underlying condition the Code First note names is documented alongside this condition.

Coding question: How are the two sequenced?

Path: Review the Code First note.

Reason: The underlying condition is sequenced first and the manifestation follows (Guidelines I.A.13).

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Code Overview

Sequelae of inflammatory diseases of central nervous system is a billable ICD-10-CM diagnosis code (G09).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Indexed Clinical Terms (14)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

Verify Before Coding

  • No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

MS-DRG Grouper Relationships (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 MS-DRG: not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity for that release.

Named in the grouper logic of 3 MS-DRGs: DRG 091 (MDC 01), DRG 092 (MDC 01), DRG 093 (MDC 01).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):NVS022 — Sequela of specified nervous system conditions (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Sequela of specified nervous system conditions).

B91 — Sequelae of poliomyelitis, B94.1 — Sequelae of viral encephalitis, G65.0 — Sequelae of Guillain-Barré syndrome, G65.1 — Sequelae of other inflammatory polyneuropathy, G65.2 — Sequelae of toxic polyneuropathy

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main terms “Thrombophlebitis”, “Abscess”, “Sequelae”; these codes share that main term but sit in a different category of the Tabular List.

E64.1 — Sequelae of vitamin A deficiency (vitamin deficiency NEC, A), E64.2 — Sequelae of vitamin C deficiency (vitamin deficiency NEC, C), E64.3 — Sequelae of rickets (rickets), E64.8 — Sequelae of other nutritional deficiencies (niacin deficiency), E64.9 — Sequelae of unspecified nutritional deficiency (nutritional deficiency), E68 — Sequelae of hyperalimentation (hyperalimentation), G06.0 — Intracranial abscess and granuloma (brain), G06.1 — Intraspinal abscess and granuloma (spinal cord), G06.2 — Extradural and subdural abscess, unspecified (epidural), G08 — Intracranial and intraspinal phlebitis and thrombophlebitis (sinus), G95.19 — Other vascular myelopathies (intraspinal venous sinuses and veins, nonpyogenic), H00.03 — Abscess of eyelid (eyelid), H16.31 — Corneal abscess (cornea), H27.8 — Other specified disorders of lens (lens), H60.0 — Abscess of external ear (ear, external), I30.1 — Infective pericarditis (pericardial), I40.0 — Infective myocarditis (myocardium), I67.6 — Nonpyogenic thrombosis of intracranial venous system (sinus, nonpyogenic), I69.00 — Unspecified sequelae of nontraumatic subarachnoid hemorrhage (hemorrhage, subarachnoid), I69.020 — Aphasia following nontraumatic subarachnoid hemorrhage (hemorrhage, subarachnoid, aphasia), +301 more

Contextual Map

Every relationship of G09 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Hierarchy

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 01 — Diseases and Disorders of the Nervous System[MDC crossing]: “Diseases and Disorders of the Nervous System — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 8,919 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027

Index entries (14)

  • Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic), cerebellum, cerebellar, sequelae[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic), cerebral (embolic), sequelae[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic), extradural, brain, sequelae[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic), subdural, brain, sequelae[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Parencephalitis, sequelae[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Sequelae (of), abscess, intracranial or intraspinal (conditions in G06)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Sequelae (of), encephalitis or encephalomyelitis (conditions in G04)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Sequelae (of), infection, pyogenic, intracranial or intraspinal[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • and 6 more

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2027 tabular list, index and tables, effective October 1, 2026 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v44.0 (October 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v44 Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "G09 — Sequelae of inflammatory diseases of central nervous system." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/g09-sequelae-of-inflammatory-diseases-of-central-nervous-system

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Sequelae of inflammatory diseases of central nervous system

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027, and none are recorded for this code. Note changes are tracked from FY2027 only.