2026 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 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G03.1 is a billable ICD-10-CM diagnosis code for chronic meningitis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). 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

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Meningitis(basal) (basic) (brain) (cerebral) (cervical) (congestive) (diffuse) (hemorrhagic) (infantile) (membranous) (metastatic) (nonspecific) (pontine) (progressive) (simple) (spinal) (subacute) (sympathetic) (toxic)
      • chronic NEC

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

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

Clinical InformationClinical

  • Arachnoiditis

    acute or chronic inflammation of the arachnoid membrane of the meninges most often involving the spinal cord or base of the brain. this term generally refers to a persistent inflammatory process characterized by thickening of the arachnoid membrane and dural adhesions. associated conditions include prior surgery, infections, trauma, subarachnoid hemorrhage, and chemical irritation. clinical features vary with the site of inflammation, but include cranial neuropathies, radiculopathies, and myelopathies. (from joynt, clinical neurology, 1997, ch48, p25)

  • Grade 2 Arachnoiditis, CTCAE|Grade 2 Arachnoiditis

    moderate symptoms; limiting instrumental adl or mild/moderate impact on age-appropriate normal daily activity (pediatric)

  • Grade 3 Arachnoiditis, CTCAE|Grade 3 Arachnoiditis

    severe symptoms; limiting self-care adl or severe impact on age-appropriate normal daily activity (pediatric)

  • Arachnoiditis

    inflammation of the arachnoid membrane and adjacent subarachnoid space.

  • Arachnoiditis, CTCAE|Arachnoiditis|Arachnoiditis

    a disorder characterized by inflammation of the arachnoid membrane and adjacent subarachnoid space.

  • Grade 1 Arachnoiditis, CTCAE|Grade 1 Arachnoiditis

    mild symptoms

  • Grade 2 Arachnoiditis, CTCAE|Grade 2 Arachnoiditis

    moderate symptoms; limiting instrumental adl

  • Grade 3 Arachnoiditis, CTCAE|Grade 3 Arachnoiditis

    severe symptoms; limiting self care adl

  • Grade 4 Arachnoiditis, CTCAE|Grade 4 Arachnoiditis

    life-threatening consequences; urgent intervention indicated

  • Grade 5 Arachnoiditis, CTCAE|Grade 5 Arachnoiditis

    death

  • Spinal Arachnoiditis

    a chronic adhesive arachnoiditis in the spinal arachnoid, with root and spinal cord symptoms similar to those caused by pressure from a tumor.

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 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About G03.1Overview

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, 2025 through September 30, 2026.

What is the ICD-9 equivalent of G03.1?

Under the General Equivalence Mappings, chronic meningitis converts to ICD-9-CM 322.2 (chronic meningitis). The mapping is a direct match.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.