ICD10BillableValid for clinical use
ICD-10 Code G90.2: Horner's syndrome
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 horner's syndrome 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
G90Disorders of autonomic nervous system
currentG90
Official coding notes
Inclusion terms
- Bernard(-Horner) syndrome
- Cervical sympathetic dystrophy or paralysis
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
G90.0Idiopathic peripheral autonomic neuropathycategoryG90.1Familial dysautonomia [Riley-Day]codeG90.3Multi-system degeneration of the autonomic nervous systemcodeG90.4Autonomic dysreflexiacodeG90.5Complex regional pain syndrome I (CRPS I)categoryG90.8Other disorders of autonomic nervous systemcategoryG90.9Disorder of the autonomic nervous system, unspecifiedcodeG90.APostural orthostatic tachycardia syndrome [POTS]codeG90.BLMNB1-related autosomal dominant leukodystrophycode
Sibling codes
G90.0Idiopathic peripheral autonomic neuropathyG90.1Familial dysautonomia [Riley-Day]billableG90.3Multi-system degeneration of the autonomic nervous systembillableG90.4Autonomic dysreflexiabillableG90.5Complex regional pain syndrome I (CRPS I)G90.8Other disorders of autonomic nervous systemG90.9Disorder of the autonomic nervous system, unspecifiedbillableG90.APostural orthostatic tachycardia syndrome [POTS]billableG90.BLMNB1-related autosomal dominant leukodystrophybillable
Coverage-related procedures and services
HCPCS G0255high
CURRENT PERCEPTION THRESHOLD/SENSORY NERVE CONDUCTION TEST, (SNCT) PER LIMB, ANY NERVE
Source: CMS coverage guidance
CPT 95905high
MOTOR AND/OR SENSORY NERVE CONDUCTION, USING PRECONFIGURED ELECTRODE ARRAY(S), AMPLITUDE AND LATENCY/VELOCITY STUDY, EACH LIMB, INCLUDES F-WAVE STUDY WHEN PERFORMED, WITH INTERPRETATION AND REPORT
Source: CMS coverage guidance
CPT 95907high
NERVE CONDUCTION STUDIES; 1-2 STUDIES
Source: CMS coverage guidance
CPT 95912high
NERVE CONDUCTION STUDIES; 11-12 STUDIES
Source: CMS coverage guidance
CPT 95913high
NERVE CONDUCTION STUDIES; 13 OR MORE STUDIES
Source: CMS coverage guidance
CPT 95908high
NERVE CONDUCTION STUDIES; 3-4 STUDIES
Source: CMS coverage guidance
Mapped diagnoses and classifications
SNOMED_CT 721537005high
Acquired Horner syndrome
Source: SNOMED International ICD-10 map
SNOMED_CT 789431002high
Acquired left-sided Horner syndrome
Source: SNOMED International ICD-10 map
SNOMED_CT 789430001high
Acquired right-sided Horner syndrome
Source: SNOMED International ICD-10 map
SNOMED_CT 770626007high
Congenital Horner syndrome
Source: SNOMED International ICD-10 map
SNOMED_CT 1281810006high
Horner syndrome
Source: SNOMED International ICD-10 map
SNOMED_CT 192915005high
Paralysis of cervical sympathetic trunk
Source: SNOMED International ICD-10 map
Coding guidelines
Compatibility
Legacy and official ICD code match exactly.
Legacy codes
G90.2
Common synonyms
Horner's syndrome
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.