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ICD10

ICD-10 Code I63.21: Cerebral infarction due to unspecified occlusion or stenosis of vertebral arteries

I63.21 is an ICD-10 diagnosis entry used to group records related to Cerebral infarction due to unspecified occlusion or stenosis of vertebral arteries. You may see this entry in coding references, medical records, or claims workflows when a broader diagnosis category is being reviewed before a more specific code is chosen. ICD-10 entries help standardize how diagnoses are organized for coding, reporting, analytics, and documentation. This code sits within the broader ICD-10 area for Diseases of the circulatory system (I00-I99).

What is this code?

ICD-10 entries help standardize how diagnoses are organized for coding, reporting, analytics, and documentation. This code sits within the broader ICD-10 area for Diseases of the circulatory system (I00-I99).

đź“‹Clinical overview

This ICD-10 code is commonly used when documentation describes cerebral infarction attributed to unspecified occlusion or stenosis of a precerebral artery. The most accurate code depends on whether the record later clarifies the exact artery or a more specific thrombotic versus embolic mechanism.

When is it used?

  • May be used when a clinician documents cerebral infarction due to unspecified occlusion or stenosis of vertebral arteries in a patient's medical record.
  • May appear in hospital records, claims, referrals, and clinical documentation.
  • This code may act more like a grouping or parent code, so a more specific child code may be used in final documentation when available.

What it does not mean

  • A code alone does not explain severity, treatment plan, or outcome.
  • A medical code should not be treated as a substitute for a doctor's diagnosis or advice.
  • This entry may represent a broader category rather than the most specific billable code.

đź©şClinical context

When commonly used
  • Stroke, neurology, inpatient, and utilization-review documentation where ischemic stroke is linked to precerebral arterial occlusion but the record does not clearly distinguish thrombosis from embolism.
  • Coding workflows where the chart identifies vertebral, basilar, carotid, unspecified, or another precerebral artery but preserves broader occlusion or stenosis language.
Common management context
  • Evaluation often includes neurologic examination, vascular imaging review, acute-stroke assessment context, and follow-up of ischemic deficits or stroke-risk factors.
  • Documentation usually becomes more specific when the chart clarifies whether the occlusive event is thrombotic versus embolic and names the exact artery involved.
  • Specialist context already linked on this page includes Cardiologist, General Physician, Neurologist, Stroke Specialist.

🔍Key distinctions

Important notes
  • These ICD-10 codes describe ischemic stroke attributed to a broader unspecified occlusion or stenosis pattern in a precerebral artery rather than clearly documented thrombosis or embolism.
  • Specific artery detail such as carotid, vertebral, basilar, or other precerebral involvement can change the final code.
  • Documentation that attributes cerebral infarction to unspecified occlusion or stenosis of precerebral arteries is coded differently from infarction due to thrombosis or embolism of similar precerebral arteries.
Related codes to consider
I63.211Cerebral infarction due to unspecified occlusion or stenosis of right vertebral artery
Related cerebral-infarction ICD-10 code; documentation often becomes more specific when the chart identifies thrombosis versus embolism, the exact artery, laterality, or another occlusive mechanism.
I63.212Cerebral infarction due to unspecified occlusion or stenosis of left vertebral artery
Related cerebral-infarction ICD-10 code; documentation often becomes more specific when the chart identifies thrombosis versus embolism, the exact artery, laterality, or another occlusive mechanism.
I63.213Cerebral infarction due to unspecified occlusion or stenosis of bilateral vertebral arteries
Related cerebral-infarction ICD-10 code; documentation often becomes more specific when the chart identifies thrombosis versus embolism, the exact artery, laterality, or another occlusive mechanism.
I63.219Cerebral infarction due to unspecified occlusion or stenosis of unspecified vertebral artery
Related cerebral-infarction ICD-10 code; documentation often becomes more specific when the chart identifies thrombosis versus embolism, the exact artery, laterality, or another occlusive mechanism.

Code hierarchy

chapter
9Diseases of the circulatory system (I00-I99)
block
I60-I69Cerebrovascular diseases
category
I63Cerebral infarction
category
I63.2Cerebral infarction due to unspecified occlusion or stenosis of precerebral arteries
currentI63.2

Where you may see this code

You may see this entry in coding references, medical records, or claims workflows when a broader diagnosis category is being reviewed before a more specific code is chosen.

Related specialists

CardiologistGeneral PhysicianNeurologistStroke Specialist

Coding guidelines

Common synonyms

Cerebral infarction due to unspecified occlusion or stenosis of vertebral arteriesCerebral infarction due to occlusion or stenosis of vertebral arteries

Frequently asked questions

Code details

CodeI63.21
SystemICD10
Display nameCerebral infarction due to unspecified occlusion or stenosis of vertebral arteries
ChapterDiseases of the circulatory system (I00-I99)
BlockCerebrovascular diseases

Flags

BillableNo
Valid clinical useNo

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.