2026 ICD-10-CM Diagnosis Code G46.4Cerebellar stroke syndrome

ICD-10-CM Codes›G00–G99›G40-G47›G46

ICD-10-CM G46.4
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G46.4 is a billable ICD-10-CM diagnosis code for cerebellar stroke syndrome. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). Coders also document this condition as cerebellar infarction. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other and ill-defined cerebrovascular disease and Other nervous system disorders (neither hereditary nor degenerative).

Code Identity

ICD-10-CM Code
G46.4
Billable Status
Yes — Valid for Submission
Code Describes
Cerebellar stroke syndrome
Short Description
Cerebellar stroke syndrome
Same as the full description in the CMS dataset.
Parent Code
G46
Vascular syndromes of brain in cerebrovascular diseases

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG40-G47Episodic and paroxysmal disorders
CategoryG46Vascular syndromes of brain in cerebrovascular diseases
This CodeG46.4Cerebellar stroke syndrome

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Cerebellar infarction
  • Cerebellar stroke syndrome
  • Posterior cerebral circulation infarction

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.

    • Syndrome
      • cerebellar
        • stroke
    • Syndrome
      • dorsolateral medullary
    • Syndrome
      • lateral
        • medullary

Clinical ClassificationClinical

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

CCSR CIR024
Other and ill-defined cerebrovascular disease
Default principal diagnosis: inpatient No · outpatient No
CCSR NVS020
Other nervous system disorders (neither hereditary nor degenerative)
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Cerebellar Disorders

When you play the piano or hit a tennis ball you are activating the cerebellum. The cerebellum is the area of the brain that controls coordination and balance. Problems with the cerebellum include:

Read the full article at MedlinePlus

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

Convert G46.4 to ICD-9-CMHistory

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

ICD-9-CM
437.8 Cerebrovasc disease NEC
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 G46.4Overview

Is G46.4 (Vascular syndromes of brain in cerebrovascular diseases) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report cerebellar stroke syndrome on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of G46.4?

Under the General Equivalence Mappings, cerebellar stroke syndrome converts to ICD-9-CM 437.8 (cerebrovasc disease NEC). 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.