⚕️ICD-10 CM G93.1 - Anoxic brain damage, not elsewhere classified

Code Description

ICD-10 CM G93.1 represents Anoxic brain damage, not elsewhere classified. This code is used to document permanent damage to the brain caused by a lack of oxygen supply (anoxia or hypoxia) that is not due to trauma, cerebral infarction, or conditions originating in the perinatal period. It signifies a chronic or residual neurological deficit resulting from oxygen deprivation.^{CMS ICD-10}

Clinical Overview

Anoxic brain damage occurs when the brain is completely deprived of oxygen. This can result from cardiac arrest, respiratory failure, drowning, carbon monoxide poisoning, or severe hypotension. The severity of the damage depends on the duration of oxygen deprivation. Clinical manifestations may range from mild cognitive impairment to persistent vegetative state or coma.^NINDS

Coding Hierarchy (Code Tree)

This code exists within the following hierarchy in the ICD-10-CM structure:

Chapter VI: Diseases of the nervous system (G00-G99)
- Block: Other disorders of brain (G93-G94)
  - Category: Other disorders of brain (G93)
    - Subcategory: Anoxic brain damage, not elsewhere classified (G93.1)

Official Coding Guidelines & Notes

Includes

This code includes conditions specified as:

Anoxic brain damage NOS
Hypoxic brain damage NOS^{WHO ICD-10}

Excludes1

Note: Excludes1 means “not coded here”. If the patient has this condition, do not use G93.1. Code the excluded condition instead.

Cerebral infarction (I63.-)
Neonatal anoxic brain damage (P91.6-)
Traumatic brain injury (S06.-)^{CMS ICD-10}

Excludes2

Note: Excludes2 means “not included here”. The patient may have both conditions, but code separately.

None specifically listed at this subcategory level. Refer to parent code G93 for broader exclusions.^{CMS ICD-10}

Coding Tips

Underlying Cause: Code first the underlying cause of the anoxia if known (e.g., Cardiac Arrest I46.9, Respiratory Failure J96.90, Drowning T75.1).^{Coding Clinic}
Coma Status: If the patient is in a coma, assign an additional code from category R40 (Coma) to specify the level of consciousness (e.g., R40.20 Unspecified coma).
Sequelae: If the encounter is for sequelae of a previous acute event (e.g., old cardiac arrest), code the residual condition (G93.1) first, followed by the sequelae code of the cause.^{CMS ICD-10}
Trauma: If the anoxic damage is due to head trauma, do not use G93.1; use the appropriate traumatic brain injury code from chapter 19.^{CMS ICD-10}

Reimbursement & Risk Adjustment

HCC (Hierarchical Condition Category)

Status: Yes
Model: CMS-HCC V28 (2024 Model)
Category: This code typically maps to HCC categories related to Severe Neurological Conditions (e.g., HCC 54).^{CMS Risk Adjustment}
Impact: Documenting G93.1 accurately ensures proper capture of patient complexity and risk adjustment payment eligibility, as this condition implies significant chronic disability and resource utilization.

wRVU (Work Relative Value Unit)

Value: N/A
Reason: G93.1 is an ICD-10-CM diagnosis code. wRVU values are assigned to CPT/HCPCS procedure codes (e.g., 99291), not diagnosis codes.^{AMA CPT}

Assistant Surgeon Payable

Status: N/A
Reason: Assistant surgeon modifiers (e.g., 80, 81, 82) apply to surgical CPT codes. Diagnosis codes do not have assistant payable status.^{CMS MPFS}

Applicability: Yes
Impact: G93.1 influences DRG assignment when used as a principal or secondary diagnosis in inpatient settings.
MDC: Typically falls under MDC 01 (Diseases and Disorders of the Nervous System).
CC/MCC: May qualify as a Complication or Comorbidity (CC) or Major Complication or Comorbidity (MCC) depending on the specific DRG logic and presence of other conditions (e.g., mechanical ventilation), potentially increasing reimbursement weight.^{CMS MS-DRG}

Coding Examples

Example 1: Post-Cardiac Arrest

Scenario: A patient is admitted following a cardiac arrest outside the hospital. They are resuscitated but remain comatose with evidence of anoxic brain injury.

Primary Diagnosis: G93.1 (Anoxic brain damage, not elsewhere classified)
Secondary Diagnosis: I46.9 (Cardiac arrest, cause unspecified)
Secondary Diagnosis: R40.20 (Unspecified coma)
Note: Sequence based on reason for admission. If admission is for management of the brain damage, G93.1 may be principal.^{Coding Clinic}

Example 2: Respiratory Failure Sequelae

Scenario: Patient with history of severe respiratory failure now presents with chronic cognitive deficits due to prior hypoxia.

Primary Diagnosis: G93.1 (Anoxic brain damage, not elsewhere classified)
Secondary Diagnosis: J96.90 (Respiratory failure, unspecified, unspecified whether with hypoxia or hypercapnia)
Note: Link the chronic condition to the prior acute event if applicable.^{CMS ICD-10}

Example 3: Critical Care Management

Scenario: Patient with anoxic brain damage requires critical care services for hemodynamic support.

Diagnosis: G93.1
Procedure: 99291 (Critical care, evaluation and management of the critically ill or critically injured patient; first 30-74 minutes)
Note: Ensure documentation supports critical care criteria.^{AMA CPT}

While G93.1 does not use modifiers, associated E/M or Procedure codes might:

-25: Significant, Separately Identifiable Evaluation and Management Service by the Same Physician or Other Qualified Health Care Professional on the Same Day of the Procedure or Other Service.
-59: Distinct Procedural Service.
-74: Discontinued Out-Patient Hospital/ASC Procedure After Administration of Anesthesia.
-CR: Catastrophe/Disaster Related (if applicable to specific disaster relief billing).
-DR: Disaster Related (alternative modifier for disaster scenarios).^{AMA CPT}

Sources

^{CMS ICD-10} Centers for Medicare & Medicaid Services, ICD-10-CM Official Guidelines for Coding and Reporting. ^NINDS National Institute of Neurological Disorders and Stroke, Anoxic Encephalopathy Information Page. ^{WHO ICD-10} World Health Organization, ICD-10 Version:2019. ^{Coding Clinic} AHA Coding Clinic for ICD-10-CM/PCS. ^{CMS Risk Adjustment} CMS Medicare Advantage Risk Adjustment Data Processing System. ^{AMA CPT} American Medical Association, CPT Professional Edition. ^{CMS MPFS} CMS Medicare Physician Fee Schedule. ^{CMS MS-DRG} CMS Medicare Severity Diagnosis Related Groups Definitions Manual.

Explorer

G93.1