2026 ICD-10-CM Diagnosis Code S06.82AAInjury of left internal carotid artery, intracranial portion, not elsewhere classified with loss of consciousness status unknown, initial encounter

ICD-10-CM Codes›S00–T88›S00-S09›S06

ICD-10-CM S06.82AA
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

S06.82AA is a billable ICD-10-CM diagnosis code for injury of left internal carotid artery, intracranial portion, not elsewhere classified with loss of consciousness status unknown, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 963 through 965. Coders also document this condition as carotid cavernous fistula. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Traumatic brain injury (TBI); concussion, initial encounter.

Code Identity

ICD-10-CM Code
S06.82AA
Billable Status
Yes — Valid for Submission
Code Describes
Injury of left internal carotid artery, intracranial portion, not elsewhere classified with loss of consciousness status unknown, initial encounter
Short Description
Inj l int crtd, intcrn portion, NEC LOC status unknown, init
Parent Code
S06.82A
Injury of left internal carotid artery, intracranial portion, not elsewhere classified with loss of consciousness status unknown

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS00-S09Injuries to the head
CategoryS06Intracranial injury
This CodeS06.82AAInjury of left internal carotid artery, intracranial portion, not elsewhere classified with loss of consciousness status unknown, initial encounter

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Carotid cavernous fistula
  • Injury of internal carotid artery
  • Left carotid artery injury
  • Traumatic carotid cavernous fistula
  • Traumatic left carotid cavernous fistula

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Intracranial injury (S06). Use the following options for the applicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.

Clinical ClassificationClinical

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

CCSR INJ008
Traumatic brain injury (TBI); concussion, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Code History & ChangesHistory

Replacement S06.82AA replaces the following previously assigned code(s):

  • S06.829A - Injury of l int carotid, intcr w LOC of unsp duration, init
FY 2023AddedAdded to the ICD-10-CM code setEffective October 1, 2022.
FY 2024–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About S06.82AAOverview

Is S06.82AA a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report injury of left internal carotid artery, intracranial portion, not elsewhere classified with loss of consciousness status unknown, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character A in S06.82AA mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for injury of left internal carotid artery, intracranial portion, not elsewhere classified with loss of consciousness status unknown, such as an emergency visit or first evaluation.

What MS-DRG does S06.82AA group to?

When injury of left internal carotid artery, intracranial portion, not elsewhere classified with loss of consciousness status unknown, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 963, 964, 965, with relative weights from 0.9405 to 2.7338 depending on complications. Higher weights mean higher Medicare reimbursement.

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.