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G05.4 ICD-10-CM Code: Myelitis in diseases classified elsewhere

Compare with another codeCheck this code on a claim

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

Coding at a Glance

Tabular directives
1 inclusion term · 11 Excludes1 · 10 code-first instructions
Risk adjustment
CMS-HCC V28: 1 category · CMS-HCC V22 category 72 · RxHCC V08 category 155

Billable · FY2027A valid, specific ICD-10-CM code, reportable for dates of service in FY2027.

What you need to know

Source: CMS/NCHS Official ICD-10-CM tabular notes, quoted. From the CMS/NCHS tabular list for the release in force. A note the category or block publishes applies to this code too; the Instructions section marks which is which.

Code firstSequence the underlying condition before this code
  • underlying disease, such as:
  • congenital toxoplasmosis encephalitis, myelitis and encephalomyelitis (P37.1)
  • cytomegaloviral encephalitis, myelitis and encephalomyelitis (B25.8)
  • encephalitis, myelitis and encephalomyelitis (in) systemic lupus erythematosus (M32.19)

+6 more in Instructions

Excludes1Never report with this code
  • adenoviral encephalitis, myelitis and encephalomyelitis (A85.1)
  • encephalitis, myelitis and encephalomyelitis (in) measles (B05.0)
  • enteroviral encephalitis, myelitis and encephalomyelitis (A85.0)
  • herpesviral [herpes simplex] encephalitis, myelitis and encephalomyelitis (B00.4)

+7 more in Instructions

IncludesWhat this code covers
  • Meningomyelitis in diseases classified elsewhere

Most relevant related codes MedCoder-derived

Read off the official notes above and this code’s own position in the tabular list. Which to report is a documentation question; Compare shows the two side by side.

CompareCheck ClaimView Related Codes

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 023 — CRANIOTOMY WITH MAJOR DEVICE IMPLANT OR ACUTE COMPLEX CNS PRINCIPAL DIAGNOSIS WITH MCC OR ANTINEOPLASTIC IMPLANT OR EPILEPSY WITH NEUROSTIMULATOR (MDC 01)
  • MS-DRG 024 — CRANIOTOMY WITH MAJOR DEVICE IMPLANT OR ACUTE COMPLEX CNS PRINCIPAL DIAGNOSIS WITHOUT MCC (MDC 01)
  • MS-DRG 097 — NON-BACTERIAL INFECTION OF NERVOUS SYSTEM EXCEPT VIRAL MENINGITIS WITH MCC (MDC 01)
  • MS-DRG 098 — NON-BACTERIAL INFECTION OF NERVOUS SYSTEM EXCEPT VIRAL MENINGITIS WITH CC (MDC 01)
  • MS-DRG 099 — NON-BACTERIAL INFECTION OF NERVOUS SYSTEM EXCEPT VIRAL MENINGITIS 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.

Risk Adjustment (CMS-HCC)

Payment categories this diagnosis maps to under CMS-HCC V28, payment year 2026.

  • HCC 182 — Spinal Cord Disorders/Injuries

Other models: CMS-HCC V22 HCC 72 · RxHCC V08 HCC 155

Risk scores depend on the enrollee's full accepted diagnosis set and segment; a category mapping alone does not determine payment.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for G05.4 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

Notes without a marker are published on G05.4 itself; “inherited from” names the category or block whose note applies here.

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Meningomyelitis in diseases classified elsewhere

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Source: inherited from G05

Code First

Underlying conditions that must be sequenced before this code.

  • underlying disease, such as:
  • congenital toxoplasmosis encephalitis, myelitis and encephalomyelitis (P37.1)
  • cytomegaloviral encephalitis, myelitis and encephalomyelitis (B25.8)
  • encephalitis, myelitis and encephalomyelitis (in) systemic lupus erythematosus (M32.19)
  • eosinophilic meningoencephalitis (B83.2)
  • human immunodeficiency virus [HIV] disease (B20)
  • poliovirus (A80.-)
  • suppurative otitis media (H66.01-H66.4)
  • systemic lupus erythematosus (M32.19)
  • trichinellosis (B75)

Source: inherited from G05

Coder workflow for G05.4

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

Before you code G05.4

  1. G05.4 is a manifestation code (“in diseases classified elsewhere”). Confirm the underlying condition is documented and sequence it first; a manifestation code is not reported as the first-listed or principal diagnosis. The etiology/manifestation convention (Guidelines I.A.13).

    See the official tabular notes · Guide: Manifestation codes and Code First sequencing →

  2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with G05.4. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

    See the official tabular notes

Choose the right path

  1. Does the documentation support a condition named in G05.4’s Excludes1 note?
    Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
    No → Continue.

    ReviewA85.1, B05.0, A85.0, B00.4, A32.12, A39.81

  2. Is the underlying (etiologic) condition the Code First note names documented?
    Yes → Sequence the underlying condition first, then G05.4.
    No → A manifestation code needs its underlying condition — query before reporting it.

    ReviewP37.1, B25.8, M32.19, B83.2, B20, A80

Consider G05.4. 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

  • Excludes1 — check before selecting G05.4(11 notes)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with G05.4: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareA85.1, B05.0, A85.0, B00.4, A32.12, A39.81

    See the official tabular notes · Guidelines I.A.12.a

  • Code First — sequencing check(10 notes)

    Coding workflow: Check whether the underlying or etiologic condition the note names is documented. When it is, sequence it before G05.4. Do not add an underlying condition the record does not document.

    ReviewP37.1, B25.8, M32.19, B83.2, B20, A80

    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: Both the condition G05.4 describes and a condition named in its Excludes1 note are documented for the same encounter.

Coding question: Can both codes be reported?

Path: Review the Excludes1 note and the excluded code, and look for a provider statement on whether the two conditions are related.

Reason: Excludes1 means the two are not coded together; the exception is when the record shows the conditions are unrelated to each other (Guidelines I.A.12.a).

ReviewA85.1, B05.0, A85.0, B00.4, A32.12, A39.81

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).

ReviewP37.1, B25.8, M32.19, B83.2, B20, A80

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.

Don’t confuse G05.4 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of G05.4 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

  • A85.1— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of adenoviral encephalitis, myelitis and encephalomyelitis moves the case to A85.1; the two are not reported together unless documented as unrelated.

    Full comparison: G05.4 vs A85.1 →

  • B05.0— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of encephalitis, myelitis and encephalomyelitis (in) measles moves the case to B05.0; the two are not reported together unless documented as unrelated.

    Full comparison: G05.4 vs B05.0 →

  • A85.0— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of enteroviral encephalitis, myelitis and encephalomyelitis moves the case to A85.0; the two are not reported together unless documented as unrelated.

    Full comparison: G05.4 vs A85.0 →

  • B00.4— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of herpesviral [herpes simplex] encephalitis, myelitis and encephalomyelitis moves the case to B00.4; the two are not reported together unless documented as unrelated.

    Full comparison: G05.4 vs B00.4 →

  • A32.12— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of listerial encephalitis, myelitis and encephalomyelitis moves the case to A32.12; the two are not reported together unless documented as unrelated.

    Full comparison: G05.4 vs A32.12 →

  • A39.81— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of meningococcal encephalitis, myelitis and encephalomyelitis moves the case to A39.81; the two are not reported together unless documented as unrelated.

    Full comparison: G05.4 vs A39.81 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Coding context

Guidelines, coding notes, decision aids, relationships (with MS-DRG and CCSR classification), hierarchy, HCC, coverage and the context map: what a coder reaches for after the core. Each section names whether it is official source data, a MedCoder-derived relationship or MedCoder editorial.

Code Overview

Myelitis in diseases classified elsewhere is a billable ICD-10-CM diagnosis code (G05.4).

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

Verify Before Coding

  • Principal-diagnosis restriction. This is a manifestation code: the Medicare Code Editor requires the underlying condition (etiology) to be sequenced first, with this code reported after it.
  • MCC as a secondary diagnosis (FY2027). Can raise the stay's MS-DRG severity tier.

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-derived relationships — computed from published CMS and AHRQ datasets

MS-DRG Grouper Relationships (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 MS-DRG: MCC — Major Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 182 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 5 MS-DRGs: DRG 023 (MDC 01), DRG 024 (MDC 01), DRG 097 (MDC 01), DRG 098 (MDC 01), DRG 099 (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):NVS002 — Encephalitis.

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 process (MS-DRG)

Acts as MCC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

G03.9 — Meningitis, unspecified, G04.00 — Acute disseminated encephalitis and encephalomyelitis, unspecified, G04.01 — Postinfectious acute disseminated encephalitis and encephalomyelitis (postinfectious ADEM), G04.2 — Bacterial meningoencephalitis and meningomyelitis, not elsewhere classified, G04.31 — Postinfectious acute necrotizing hemorrhagic encephalopathy, G04.81 — Other encephalitis and encephalomyelitis, G04.82 — Acute flaccid myelitis, G04.89 — Other myelitis, G04.90 — Encephalitis and encephalomyelitis, unspecified, G04.91 — Myelitis, unspecified, G37.0 — Diffuse sclerosis of central nervous system, G37.4 — Subacute necrotizing myelitis of central nervous system, G37.5 — Concentric sclerosis [Balo] of central nervous system, G61.0 — Guillain-Barre syndrome, G96.9 — Disorder of central nervous system, unspecified, G98.0 — Neurogenic arthritis, not elsewhere classified, G98.8 — Other disorders of nervous system, J09.X3 — Influenza due to identified novel influenza A virus with gastrointestinal manifestations, J09.X9 — Influenza due to identified novel influenza A virus with other manifestations, J10.2 — Influenza due to other identified influenza virus with gastrointestinal manifestations, +162 more

Principal diagnosis restriction (Medicare Code Editor)

Manifestation code — the underlying condition is sequenced first.

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Spinal Cord Disorders/Injuries) for risk-adjusted payment.

B00.82 — Herpes simplex myelitis, B01.12 — Varicella myelitis, B02.24 — Postherpetic myelitis, G04.1 — Tropical spastic paraplegia, G04.82 — Acute flaccid myelitis, G04.89 — Other myelitis, G04.91 — Myelitis, unspecified, G14 — Postpolio syndrome, G32.0 — Subacute combined degeneration of spinal cord in diseases classified elsewhere, G32.81 — Cerebellar ataxia in diseases classified elsewhere, G37.3 — Acute transverse myelitis in demyelinating disease of central nervous system, G37.4 — Subacute necrotizing myelitis of central nervous system, G83.4 — Cauda equina syndrome, G90.1 — Familial dysautonomia [Riley-Day], G95.0 — Syringomyelia and syringobulbia, G95.11 — Acute infarction of spinal cord (embolic) (nonembolic), G95.19 — Other vascular myelopathies, G95.20 — Unspecified cord compression, G95.29 — Other cord compression, G95.81 — Conus medullaris syndrome, +230 more

Related risk categories

These categories interact through CMS's HCC hierarchy — one can suppress the other's risk-adjustment weight when both are present on a claim.

Quadriplegia, Paraplegia

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Encephalitis).

B10.09 — Other human herpesvirus encephalitis, B26.2 — Mumps encephalitis, B40.81 — Blastomycotic meningoencephalitis, B57.42 — Meningoencephalitis in Chagas' disease, B58.2 — Toxoplasma meningoencephalitis, B60.11 — Meningoencephalitis due to Acanthamoeba (culbertsoni), G04.00 — Acute disseminated encephalitis and encephalomyelitis, unspecified, G04.01 — Postinfectious acute disseminated encephalitis and encephalomyelitis (postinfectious ADEM), G04.02 — Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis, G04.2 — Bacterial meningoencephalitis and meningomyelitis, not elsewhere classified, G04.30 — Acute necrotizing hemorrhagic encephalopathy, unspecified, G04.31 — Postinfectious acute necrotizing hemorrhagic encephalopathy, G04.32 — Postimmunization acute necrotizing hemorrhagic encephalopathy, G04.39 — Other acute necrotizing hemorrhagic encephalopathy, G04.81 — Other encephalitis and encephalomyelitis, G04.82 — Acute flaccid myelitis, G04.89 — Other myelitis, G04.90 — Encephalitis and encephalomyelitis, unspecified, G04.91 — Myelitis, unspecified, G05.3 — Encephalitis and encephalomyelitis in diseases classified elsewhere, +35 more

Same Index main term, other category

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

A17.82 — Tuberculous meningoencephalitis (tuberculous), A39.81 — Meningococcal encephalitis (meningococcal), A52.14 — Late syphilitic encephalitis (syphilitic), B00.82 — Herpes simplex myelitis (herpes simplex), B01.12 — Varicella myelitis (varicella), B02.24 — Postherpetic myelitis (postherpetic), B40.81 — Blastomycotic meningoencephalitis (blastomycotic NEC), B45.1 — Cerebral cryptococcosis (cryptococcal), G04.02 — Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis (postvaccinal), G04.2 — Bacterial meningoencephalitis and meningomyelitis, not elsewhere classified (bacterial NEC), G04.82 — Acute flaccid myelitis (flaccid), G04.89 — Other myelitis (specified NEC), G04.91 — Myelitis, unspecified, G36.0 — Neuromyelitis optica [Devic] (optic neuritis in), G37.3 — Acute transverse myelitis in demyelinating disease of central nervous system (transverse), G37.4 — Subacute necrotizing myelitis of central nervous system (necrotizing, subacute), G92.9 — Unspecified toxic encephalopathy (toxic)

Contextual Map

Every relationship of G05.4 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)

Risk adjustment (CMS-HCC)

  • HCC 182 — Spinal Cord Disorders/Injuries [CMS-HCC]— CMS-HCC V28 · 2026

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

  • Meningomyelitis, in diseases classified elsewhere[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Myelitis (acute) (ascending) (childhood) (chronic) (descending) (diffuse) (disseminated) (idiopathic) (pressure) (progressive) (spinal cord) (subacute), in diseases classified elsewhere[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027

Nearest codes

Change history

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

Reference

Index terms and tables, published questions and FAQ, every source behind this page with its release and checksum, the date-of-service check and the complete change history.

Indexed Clinical Terms (2)

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.

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
Risk adjustment Official source data
2026 Mid-Year Final ICD-10 Mappings + Model Software (cms.gov/files/zip/2026-midyear-final-icd-10-mappings.zip, 2026-midyear-final-model-software.zip) — CMS-HCC V28, PY2026 mid-year final release 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-derived 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 editorial 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.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 20, 2026 · All releases and sources

Labels on this page: Official source data · MedCoder-derived relationship · MedCoder editorial explanation. How to read the labels · All data sources and release dates · CMS coding rules

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. "G05.4 — Myelitis in diseases classified elsewhere." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/g05.4-myelitis-in-diseases-classified-elsewhere

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Myelitis in diseases classified elsewhere

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.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to G05.4 in its code family, with their registry titles.

View all codes in the G05 family