G91
Non-billableHydrocephalus
G91 is the ICD-10-CM code for Hydrocephalus. It is a non-billable category code — use a more specific child code such as G91.0 for billing.
- Status
- Header (non-billable)
- Chapter
- G00-G99
- Subcodes
- 7
- Edition
- FY2026
G00-G99 Diseases of the nervous system
What this means — in plain language
MedlinePlus · NIHHydrocephalus is the buildup of too much cerebrospinal fluid in the brain. Normally, this fluid cushions your brain. When you have too much, though, it puts harmful pressure on your brain. Hydrocephalus can be congenital, or present at birth. Causes include genetic problems and problems with how the fetus develops. An unusually large head is the main sign of congenital hydrocephalus. Hydrocephalus can also happen…
Read more about Hydrocephalus at MedlinePlus ↗Source: U.S. National Library of Medicine (MedlinePlus). Informational only — not medical advice.
Includes
- •acquired hydrocephalus
Excludes1 — not coded here
Conditions mapped to this code
MedlinePlus · NIHPlain-language health-topic references grounded in MedlinePlus (NIH/NLM).
Frequently asked questions
Source: CMS ICD-10-CM FY2026. For informational purposes only — not medical advice. See our medical disclaimer.
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