G91 – Hydrocephalus
ICD-10-CM 2027 diagnosis code · Other disorders of the nervous system
ICD-10-CM code
G91
- Code
G91(claims format:G91)- Description
- Hydrocephalus
- Billable
- No – use a more specific code below
- Valid for
- Dates of service October 1, 2026 – September 30, 2027 (FY2027)
- Chapter
- 6. Diseases of the nervous system (G00-G99)
- Block
- G89-G99 Other disorders of the nervous system
Billable codes under G91
G91 is a header code and cannot be used on claims. Choose the most specific code:
- G91.0 – Communicating hydrocephalusBillable
- G91.1 – Obstructive hydrocephalusBillable
- G91.2 – (Idiopathic) normal pressure hydrocephalusBillable
- G91.3 – Post-traumatic hydrocephalus, unspecifiedBillable
- G91.4 – Hydrocephalus in diseases classified elsewhereBillable
- G91.8 – Other hydrocephalusBillable
- G91.9 – Hydrocephalus, unspecifiedBillable
Notes for G91
Includes:
- acquired hydrocephalus
Frequently asked questions
What is ICD-10 code G91?
G91 is the ICD-10-CM code for hydrocephalus, in the block G89-G99 (Other disorders of the nervous system).
Is G91 a billable code?
No. G91 is a header code with more specific child codes; report one of the billable codes listed above.
Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.