2027 ICD-10-CM Diagnosis Code G03.1Chronic meningitis

ICD-10-CM Codes›G00–G99›G00-G09›G03

ICD-10-CM G03.1
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

G03.1 is a billable ICD-10-CM diagnosis code for chronic meningitis. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 97 through 99. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 106 closely related codes. Coders also document this condition as arachnoiditis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Meningitis.

Code Identity

ICD-10-CM Code
G03.1
Billable Status
Yes — Valid for Submission
Code Describes
Chronic meningitis
Short Description
Chronic meningitis
Same as the full description in the CMS dataset.
Parent Code
G03
Meningitis due to other and unspecified causes

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG00-G09Inflammatory diseases of the central nervous system
CategoryG03Meningitis due to other and unspecified causes
This CodeG03.1Chronic meningitis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Arachnoiditis
  • Chronic adhesive pachymeningitis
  • Chronic meningitis
  • Cranial arachnoiditis
  • Fibrous hypertrophic cervical pachymeningitis
  • Leptomeningitis
  • Pachymeningitis

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to G03.1: its own notes plus those printed at G03 and Chapter 6. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From G03 Meningitis due to other and unspecified causes applies to 5 codes
  • arachnoiditis NOS
  • leptomeningitis NOS
  • meningitis NOS
  • pachymeningitis NOS

Excludes1

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

From G03 Meningitis due to other and unspecified causes applies to 5 codes
  • meningoencephalitis (G04.-)
  • meningomyelitis (G04.-)

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)

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

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name G03.1, its category, or a range that includes it.

Notes 1

These notes mention G03.1.

  • 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 NVS001
Meningitis
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Meningitis

Meningitis is inflammation of the thin tissue that surrounds the brain and spinal cord, called the meninges. There are several types of meningitis. The most common is viral meningitis. You get it when a virus enters the body through the nose or mouth and travels to the brain. Bacterial meningitis is rare but can be deadly.

Read the full article at MedlinePlus

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

Convert G03.1 to ICD-9-CMHistory

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

ICD-9-CM
322.2 Chronic meningitis
Exact Match The mapping is direct, with no qualifiers.

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 G03.1Overview

What is the ICD-10 code for chronic meningitis?

The ICD-10-CM code for chronic meningitis is G03.1 (sometimes written as G031). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is G03.1 (Meningitis due to other and unspecified causes) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report chronic meningitis on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does G03.1 group to?

When chronic meningitis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 98, 99, 97, with relative weights from 1.5249 to 3.8208 depending on complications. Higher weights mean higher Medicare reimbursement.

Is G03.1 a CC or MCC?

CMS lists G03.1 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 106 closely related codes in its exclusion list.

Can G03.1 be reported with a code from G04?

Not as a rule. The Excludes1 note at G03, which applies to G03.1, lists "meningoencephalitis (G04.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).