ICD-10-CM G91 is the diagnosis code for Hydrocephalus. This code falls under the section "Other disorders of the nervous system" within Chapter 6 — Diseases of the nervous system (G00-G99). It is a non-billable/non-specific ICD-10-CM code that should not be used for reimbursement. A more specific sub-code is required for billing. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
The following conditions should never be coded at the same time as G91. They are mutually exclusive:
Understanding where G91 sits in the ICD-10-CM classification helps ensure proper coding:
No, G91 is a non-billable/non-specific code. You should use a more specific sub-code for billing and reimbursement.
G91 is the ICD-10-CM diagnosis code for "Hydrocephalus". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
G91 is located in Section G89-G99 — "Other disorders of the nervous system" within Chapter 6 of the ICD-10-CM Tabular List.
G91 has 7 sub-code(s) that provide more specific detail: G91.0, G91.1, G91.2, G91.3, G91.4 and more.
Use G91 when the patients documented diagnosis matches "Hydrocephalus" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Hydrocephalus is G91.
No, G91 is non-billable. Use a more specific sub-code for primary diagnosis billing.
G91 is in Chapter 6 of the ICD-10-CM Tabular List.
Type 1 Excludes for G91 include: Arnold-Chiari syndrome with hydrocephalus (Q07.-); congenital hydrocephalus (Q03.-); spina bifida with hydrocephalus (Q05.-).
Yes, G91 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.