2026 ICD-10-CM Diagnosis Code G13.2Systemic atrophy primarily affecting the central nervous system in myxedema

ICD-10-CM Codes›G00–G99›G10-G14›G13

ICD-10-CM G13.2
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G13.2 is a billable ICD-10-CM diagnosis code for systemic atrophy primarily affecting the central nervous system in myxedema. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). 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 Other nervous system disorders (neither hereditary nor degenerative).

Code Identity

ICD-10-CM Code
G13.2
Billable Status
Yes — Valid for Submission
Code Describes
Systemic atrophy primarily affecting the central nervous system in myxedema
Short Description
Systemic atrophy primarily affecting the cnsl in myxedema
Parent Code
G13
Systemic atrophies primarily affecting central nervous system in diseases classified elsewhere

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG10-G14Systemic atrophies primarily affecting the central nervous system
CategoryG13Systemic atrophies primarily affecting central nervous system in diseases classified elsewhere
This CodeG13.2Systemic atrophy primarily affecting the central nervous system in myxedema

Code EditsBilling

Medicare Code Editor checks that affect claim validity for G13.2.

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.

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Code First

  • underlying disease, such as:
  • hypothyroidism E03
  • myxedematous congenital iodine deficiency E00.1

Clinical ClassificationClinical

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

CCSR NVS020
Other nervous system disorders (neither hereditary nor degenerative)
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Brain Diseases

Your brain is the control center of your body. It controls your thoughts, memory, speech, and movement. It regulates the function of many organs. It's part of your nervous system, which also includes your spinal cord and peripheral nerves. The nervous system sends signals between your brain and the rest of the body.

Read the full article at MedlinePlus

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

Convert G13.2 to ICD-9-CMHistory

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

ICD-9-CM
331.7 Cereb degen in oth dis
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 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About G13.2Overview

Is G13.2 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report systemic atrophy primarily affecting the central nervous system in myxedema on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Can G13.2 be a principal diagnosis?

No. This is a manifestation code: systemic atrophy primarily affecting the central nervous system in myxedema describes the manifestation of an underlying disease rather than the disease itself, so the underlying condition is sequenced first.

What is the ICD-9 equivalent of G13.2?

Under the General Equivalence Mappings, systemic atrophy primarily affecting the central nervous system in myxedema converts to ICD-9-CM 331.7 (cereb degen in oth dis). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.