G04.90

Billable
ChapterG00–G99
Ranksubcategory
Official Description

Encephalitis and encephalomyelitis, unspecified

Metadata & Insights
  • •2026 ICD-10-CM Edition - Effective October 1, 2025.
  • •Billable/specific code (valid for reimbursement).
  • •Chapter 6: Diseases of the Nervous System (G00-G99).

Instructional Notes

Includes
  • Ventriculitis (cerebral) NOS
General instructions are available for the parent sections:
View CH6 NotesView G04 Notes

Clinical Hierarchy

CH6Diseases of the nervous system (G00-G99)
G00-G09Inflammatory diseases of the central nervous system (G00-G09)
G04Encephalitis, myelitis and encephalomyelitis
G04.9Encephalitis, myelitis and encephalomyelitis, unspecified
G04.90Encephalitis and encephalomyelitis, unspecified

Applicable Ancestor Context

The following parent sections contain instructions or notes that apply to G04.90:

categoryG04
Encephalitis, myelitis and encephalomyelitis
View context instructions
chapterCH6
Diseases of the nervous system (G00-G99)
View context instructions

Alphabetic Index Mentions

These are Diagnosis Index lookup paths that route to G04.90. Use them as entry terms for search, then confirm final coding instructions in the Tabular List and notes above.

6 raw paths
Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute)1 unique routes
Direct index entry→G04.90
Encephalomyelitis1 unique routes
Direct index entry→G04.90
Hematomyelitis1 unique routes
Direct index entry→G04.90
Infection, infected, infective (opportunistic)1 unique routes
brain→G04.90
Meningoencephalitis1 unique routes
Direct index entry→G04.90
Ventriculitis (cerebral)1 unique routes
Direct index entry→G04.90

MS-DRG Classification

2026 v43.1

This code is grouped within the following Diagnosis Related Group(s) for clinical reimbursement:

DRG 023
Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis with MCC or Antineoplastic Implant or Epilepsy with Neurostimulator
DRG 024
Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis without MCC
DRG 097
Non-Bacterial Infection of Nervous System Except Viral Meningitis with MCC
DRG 098
Non-Bacterial Infection of Nervous System Except Viral Meningitis with CC
DRG 099
Non-Bacterial Infection of Nervous System Except Viral Meningitis without CC/MCC
DRG 974
HIV with Major Related Condition with MCC
DRG 975
HIV with Major Related Condition with CC
DRG 976
HIV with Major Related Condition without CC/MCC

Cross Reference

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