ICD10BillableValid for clinical use
ICD-10 Code G99.8: Other specified disorders of nervous system in diseases classified elsewhere
Reviewed by HealthAssure Clinical TeamUpdated 26 May 2026
What is this code?
ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Diseases of the nervous system (G00-G99).
When is it used?
- May be used when a clinician documents other specified disorders of nervous system in diseases classified elsewhere in a patient's medical record.
- May appear in hospital records, claims, referrals, and clinical documentation.
- This code can be used as a clinically usable diagnosis entry in standardized coding workflows.
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.
Code hierarchy
chapter
6Diseases of the nervous system (G00-G99)
block
G89-G99Other disorders of the nervous system
category
G99Other disorders of nervous system in diseases classified elsewhere
currentG99
Official coding notes
Applicable to
- underlying disorder, such as:
- amyloidosis (E85.-)
- avitaminosis (E56.-)
Excludes1 (do not code together)
- nervous system involvement in:
- cysticercosis (B69.0)
- rubella (B06.0-)
- syphilis (A52.1-)
Code first
- underlying disorder, such as:
- amyloidosis (E85.-)
- avitaminosis (E56.-)
Where you may see this code
You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.
Related specialists
NeurologistGeneral Physician
Related codes
Sibling codes
Coverage-related procedures and services
CPT 72126high
COMPUTED TOMOGRAPHY, CERVICAL SPINE; WITH CONTRAST MATERIAL
Source: CMS coverage guidance
CPT 72125high
COMPUTED TOMOGRAPHY, CERVICAL SPINE; WITHOUT CONTRAST MATERIAL
Source: CMS coverage guidance
CPT 72127high
COMPUTED TOMOGRAPHY, CERVICAL SPINE; WITHOUT CONTRAST MATERIAL, FOLLOWED BY CONTRAST MATERIAL(S) AND FURTHER SECTIONS
Source: CMS coverage guidance
CPT 70460high
COMPUTED TOMOGRAPHY, HEAD OR BRAIN; WITH CONTRAST MATERIAL(S)
Source: CMS coverage guidance
CPT 70450high
COMPUTED TOMOGRAPHY, HEAD OR BRAIN; WITHOUT CONTRAST MATERIAL
Source: CMS coverage guidance
CPT 70470high
COMPUTED TOMOGRAPHY, HEAD OR BRAIN; WITHOUT CONTRAST MATERIAL, FOLLOWED BY CONTRAST MATERIAL(S) AND FURTHER SECTIONS
Source: CMS coverage guidance
Mapped diagnoses and classifications
SNOMED_CT 1163532007high
Adenoviral nervous system infection
Source: SNOMED International ICD-10 map
SNOMED_CT 1259059003high
Autonomic disorder due to diphtheria
Source: SNOMED International ICD-10 map
SNOMED_CT 1177014004high
Bacterial neuritis
Source: SNOMED International ICD-10 map
SNOMED_CT 77600008high
Bing-Neel syndrome
Source: SNOMED International ICD-10 map
SNOMED_CT 406562008high
Blastomyces infection of central nervous system
Source: SNOMED International ICD-10 map
SNOMED_CT 406564009high
Brucella infection of the central nervous system
Source: SNOMED International ICD-10 map
Coding guidelines
Compatibility
Legacy and official ICD code match exactly.
Legacy codes
G99.8
Common synonyms
Other specified disorders of nervous system in diseases classified elsewhere
Frequently asked questions
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.