2027 ICD-10-CM Diagnosis Code G46.3Brain stem stroke syndrome

ICD-10-CM Codes›G00–G99›G40-G47›G46

ICD-10-CM G46.3
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

G46.3 is a billable ICD-10-CM diagnosis code for brain stem stroke syndrome. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 70 through 72. 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
G46.3
Billable Status
Yes — Valid for Submission
Code Describes
Brain stem stroke syndrome
Short Description
Brain stem 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 CodeG46.3Brain stem stroke syndrome

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Alternating hemiplegia
  • Benedikt's syndrome
  • Brain stem infarction
  • Brainstem stroke syndrome
  • Cerebellar infarction
  • Claude's syndrome
  • Foville syndrome
  • Injury of facial nerve
  • Millard-Gubler syndrome
  • Paresis of extraocular muscles
  • Posterior cerebral circulation infarction
  • Posterior inferior cerebellar artery syndrome
  • Supranuclear facial nerve paralysis
  • Supranuclear paralysis
  • Third cranial nerve finding

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to G46.3: its own notes plus those printed at G46 and Chapter 6. A note printed at a category, block or chapter applies to every code under it.

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Benedikt syndrome
  • Claude syndrome
  • Foville syndrome
  • Millard-Gubler syndrome
  • Wallenberg syndrome
  • Weber syndrome

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)

Code First

The underlying condition named in the note is sequenced before this code.

From G46 Vascular syndromes of brain in cerebrovascular diseases applies to 9 codes
  • underlying cerebrovascular disease (I60-I69)

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

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 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

Clinical InformationClinical

  • Brain Stem Stroke Syndrome

    a stroke syndrome caused by infarction of the brainstem. signs and symptoms may include vertigo, ataxia, diplopia, dysarthria and an altered level of consciousness.

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 G46.3 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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About G46.3Overview

What is the ICD-10 code for brain stem stroke syndrome?

The ICD-10-CM code for brain stem stroke syndrome is G46.3 (sometimes written as G463). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is G46.3 (Vascular syndromes of brain in cerebrovascular diseases) a billable code?

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

What MS-DRG does G46.3 group to?

When brain stem stroke syndrome is the principal diagnosis on an inpatient stay, it groups to MS-DRG 72, 70, 71, with relative weights from 0.7344 to 1.6089 depending on complications. Higher weights mean higher Medicare reimbursement.

What is coded first with G46.3?

The Code First note at G46, which applies to G46.3, reads: underlying cerebrovascular disease (I60-I69). When one of these applies, it is sequenced before G46.3.

What is the ICD-9 equivalent of G46.3?

Under the General Equivalence Mappings, brain stem stroke syndrome converts to ICD-9-CM 437.8 (cerebrovasc disease NEC). The mapping is approximate, so confirm the match fits the documentation.