G91 ICD-10-CM Code: Hydrocephalus
A clear reference for the official code description, hierarchy, and related coding information from the FY 2027 U.S. release.
Official description
G91Hydrocephalus
ICD-10-CM diagnosis code · United States clinical modification
Where G91 sits
- 1
Chapter 6
Diseases of the nervous system (G00-G99)
- 2
Section
Other disorders of the nervous system (G89-G99)
- 3
Category G91
Hydrocephalus
- 4
Code G91
Hydrocephalus
Codes under G91
G91 is a non-billable category. Choose the child code that best matches the documented diagnosis.
Notes for this code
Inclusion terms
No inclusion terms are listed for G91.
Code first
No “code first” instruction is listed for G91.
Use additional code
No “use additional code” instruction is listed for G91.
Excludes1
Conditions that should not be reported together with this code.
- Arnold-Chiari syndrome with hydrocephalus (Q07.-)
- congenital hydrocephalus (Q03.-)
- spina bifida with hydrocephalus (Q05.-)
Excludes2
Conditions not included here that may be reported separately when present.
No Excludes2 note is listed for G91.
Source and release
- Data release
- U.S. ICD-10-CM · FY 2027
- Effective date
- Oct 1, 2026
- Publisher
- Vero Scribe Inc.
This reference is generated from Vero’s ICD-10-CM description, hierarchy, and code-note dataset. The visible content and structured data share that source.
Frequently asked questions
What does ICD-10-CM code G91 mean?
G91 is the FY 2027 U.S. ICD-10-CM code for “Hydrocephalus.”
Is G91 a billable or specific ICD-10-CM code?
No. G91 has more specific child codes in the FY 2027 reference data. Select the code that matches the documentation and confirm the active code set and payer requirements.
Where is G91 located in ICD-10-CM?
G91 is listed in Chapter 6, Diseases of the nervous system (G00-G99), within Other disorders of the nervous system (G89-G99) (G89–G99), under category G91, Hydrocephalus.
What coding notes are listed for G91?
No inclusion terms are listed for G91 in this reference record. No code-first instruction is listed. Excludes1 notes: Arnold-Chiari syndrome with hydrocephalus (Q07.-); congenital hydrocephalus (Q03.-); spina bifida with hydrocephalus (Q05.-). No Excludes2 note is listed.