2027 ICD-10-CM Diagnosis Code G05.3Encephalitis and encephalomyelitis in diseases classified elsewhere

ICD-10-CM Codes›G00–G99›G00-G09›G05

ICD-10-CM G05.3
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

G05.3 is a billable ICD-10-CM diagnosis code for encephalitis and encephalomyelitis in diseases classified elsewhere. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 23 through 24, 97 through 99. As a secondary diagnosis, it counts as a major complication or comorbidity (MCC) and places an inpatient stay in the highest severity level of its MS-DRG family. It does not count, however, when the principal diagnosis is one of 182 closely related codes. The code is a manifestation code that cannot be reported as the principal diagnosis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Encephalitis.

Code Identity

ICD-10-CM Code
G05.3
Billable Status
Yes — Valid for Submission
Code Describes
Encephalitis and encephalomyelitis in diseases classified elsewhere
Short Description
Encephalitis and encephalomyelitis in diseases classd elswhr
Parent Code
G05
Encephalitis, myelitis and encephalomyelitis in diseases classified elsewhere

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG00-G09Inflammatory diseases of the central nervous system
CategoryG05Encephalitis, myelitis and encephalomyelitis in diseases classified elsewhere
This CodeG05.3Encephalitis and encephalomyelitis in diseases classified elsewhere

Code EditsBilling

Medicare Code Editor checks that affect claim validity for G05.3.

Manifestation diagnoses
Manifestation codes describe the manifestation of an underlying disease, not the disease itself, and therefore should not be used as a principal diagnosis.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • African trypanosomiasis
  • Amebic encephalitis
  • Amebic infection of central nervous system
  • Arenavirus encephalitis
  • Bacterial encephalitis
  • Bacterial infectious disease of brain
  • Borrelia infection of central nervous system
  • Brainstem encephalitis
  • Coenurosis
  • Cysticercosis of brain
  • Cysticercosis of central nervous system
  • Dementia due to paraneoplastic encephalitis
  • Disease caused by Hantavirus
  • Disorder of spinal cord co-occurrent with human immunodeficiency virus infection
  • Echinococcus granulosus infection
  • Encephalitic tic disorder
  • Encephalitis caused by Borrelia
  • Encephalitis caused by Coenurus cerebralis
  • Encephalitis caused by Echinococcus granulosus
  • Encephalitis caused by human immunodeficiency virus type 1
  • Encephalitis caused by Leptospira
  • Encephalitis caused by Nocardia
  • Encephalitis caused by protozoa
  • Encephalitis caused by Schistosoma
  • Encephalitis caused by Schistosoma haematobium
  • Encephalitis caused by Schistosoma japonicum
  • Encephalitis caused by Schistosoma mansoni
  • Encephalitis caused by Taenia solium
  • Encephalitis caused by Trypanosoma brucei
  • Encephalitis caused by Trypanosoma brucei gambiense
  • Encephalitis caused by Trypanosoma brucei rhodesiense
  • Encephalitis with AIDS
  • Encephalomyelitis caused by bacterium
  • Encephalomyelitis caused by Coxiella burnetii
  • Encephalomyelitis caused by Neisseria meningitidis
  • Encephalomyelitis with AIDS
  • Encephalopathy with AIDS
  • Fungal encephalitis
  • Fungal infection of brain
  • Fungal infection of cerebrum
  • Fungal ventriculitis
  • Human immunodeficiency virus encephalitis
  • Human immunodeficiency virus I infection
  • Infection by Coenurosis cerebralis
  • Infection by Multiceps multiceps
  • Infection by Trypanosoma gambiense
  • Infection caused by Junin virus
  • Infection caused by Lassa virus
  • Infection caused by Machupo virus
  • Infection caused by Tropheryma
  • Infection causing encephalomyelitis
  • Infection of brain caused by Form Dematiaceae
  • Infection of central nervous system caused by Echinococcus
  • Infective ventriculitis
  • Junin virus encephalitis
  • Lassa virus encephalitis
  • Limbic encephalitis
  • Machupo virus encephalitis
  • Malabsorption caused by infective agent
  • Meningococcal encephalitis
  • Mycobacterial encephalomyelitis
  • Myelitis caused by bacterium
  • Myelitis co-occurrent with human immunodeficiency virus infection
  • Myelitis with AIDS
  • Myelopathy with AIDS
  • Neuro - Whipple's disease
  • Paraneoplastic encephalitis
  • Paraneoplastic encephalomyelitis
  • Paraneoplastic isolated brainstem encephalitis
  • Paraneoplastic limbic encephalitis
  • Phaeohyphomycosis
  • Primary amebic encephalitis
  • Primary encephalitis
  • Retroviridae encephalitis
  • Schistosoma encephalomyelitis
  • Schistosoma haematobium infection
  • Schistosoma japonicum infection
  • Schistosoma mansoni infection
  • Sin Nombre virus encephalitis
  • Trypanosomiasis with encephalitis
  • Ventriculitis of the brain
  • Whipple's disease

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to G05.3: its own notes plus those printed at G05 and Chapter 6. A note printed at a category, block or chapter applies to every code under it.

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Meningoencephalitis in diseases classified elsewhere

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From G05 Encephalitis, myelitis and encephalomyelitis in diseases classified elsewhere applies to 2 codes
  • 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)
  • listerial encephalitis, myelitis and encephalomyelitis (A32.12)
  • meningococcal encephalitis, myelitis and encephalomyelitis (A39.81)
  • mumps encephalitis, myelitis and encephalomyelitis (B26.2)
  • postchickenpox encephalitis, myelitis and encephalomyelitis (B01.1-)
  • rubella encephalitis, myelitis and encephalomyelitis (B06.01)
  • toxoplasmosis encephalitis, myelitis and encephalomyelitis (B58.2)
  • zoster encephalitis, myelitis and encephalomyelitis (B02.0)

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.

On G05.3 itself
  • underlying disease
From G05 Encephalitis, myelitis and encephalomyelitis in diseases classified elsewhere applies to 2 codes
  • 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: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name G05.3, its category, or a range that includes it.

Excludes1 2

These codes carry an Excludes1 note naming G05.3: they are not reported together with it, unless the two conditions are unrelated.

  • G01 Meningitis in bacterial diseases classified elsewhere
    meningoencephalitis and meningomyelitis in bacterial diseases classified elsewhere (G05) names G05, which includes this code
  • G02 Meningitis in other infectious and parasitic diseases classified elsewhere
    meningoencephalitis and meningomyelitis in other infectious and parasitic diseases classified elsewhere (G05) names G05, which includes this code

Use Additional Code 1

These codes say to use an additional code from the note, and G05.3 is one of the codes named.

  • M32.19 Other organ or system involvement in systemic lupus erythematosus
    code(s) to identify organ or system involvement, such as encephalitis (G05.3)

Notes 1

These notes mention G05.3.

  • G09 Sequelae of inflammatory diseases of central nervous system
    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. names G00-G08, which includes this code

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 NVS002
Encephalitis
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Encephalitis

Encephalitis is inflammation (swelling) of the brain. It can happen when an infection or medical condition that affects the brain activates your immune system. The inflammation can cause a wide range of symptoms. In extreme cases, it can lead to brain damage, stroke, or even death.

The full article covers:

  • What is encephalitis?
  • What causes encephalitis?
  • Who is more likely to get encephalitis?
  • What are the symptoms of encephalitis?
  • How is encephalitis diagnosed?
  • What are the treatments for encephalitis?
  • Can encephalitis be prevented?

Read the full article at MedlinePlus

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

Convert G05.3 to ICD-9-CMHistory

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

ICD-9-CM
323.41 Ot encph/mye ot inf else
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 G05.3Overview

What is the ICD-10 code for encephalitis and encephalomyelitis in diseases classified elsewhere?

The ICD-10-CM code for encephalitis and encephalomyelitis in diseases classified elsewhere is G05.3 (sometimes written as G053). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is G05.3 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report encephalitis and encephalomyelitis in diseases classified elsewhere on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does G05.3 group to?

On inpatient claims, encephalitis and encephalomyelitis in diseases classified elsewhere maps to MS-DRG 24, 98, 99, 23, 97, with relative weights from 1.5249 to 5.7422 depending on complications. Higher weights mean higher Medicare reimbursement.

Is G05.3 a CC or MCC?

CMS lists G05.3 as an MCC (major complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it places the inpatient stay in the highest-weighted DRG of its severity family. It does not count when the principal diagnosis is one of the 182 closely related codes in its exclusion list.

Can G05.3 be a principal diagnosis?

No. This is a manifestation code: encephalitis and encephalomyelitis in diseases classified elsewhere describes the manifestation of an underlying disease rather than the disease itself, so the underlying condition is sequenced first.