G91Header code — not billable

Hydrocephalus

Chapter
6. Diseases of the nervous system
Category
G91
Effective date
October 1, 2026

Related codes in category G91

G91.0Communicating hydrocephalusYesG91.1Obstructive hydrocephalusYesG91.2(Idiopathic) normal pressure hydrocephalusYesG91.3Post-traumatic hydrocephalus, unspecifiedYesG91.4Hydrocephalus in diseases classified elsewhereYesG91.8Other hydrocephalusYesG91.9Hydrocephalus, unspecifiedYes

Frequently asked questions

What is ICD-10 code G91?

G91 is an ICD-10-CM diagnosis code for Hydrocephalus.

Is G91 a billable code?

No. G91 is a category/header code, not billable on its own — use one of its more specific child codes instead.

What ICD-10-CM chapter is G91 in?

G91 falls under Chapter 6: Diseases of the nervous system.

When did G91 become effective?

G91 has been effective since October 1, 2026, per the CMS/CDC ICD-10-CM annual release.

What other codes are related to G91?

G91 belongs to category G91, which includes 7 other codes — see the related codes list on this page.

ICD-10-CM data maintained by CDC/CMS (public domain). Always verify codes with authoritative sources before making coding or billing decisions.