G91.4

Hydrocephalus in diseases classified elsewhere

FY2027Chapter 6: Diseases of the nervous system/G89–G99 Other disorders of the nervous system

BillableComplete code, valid to report

Code first
Excludes1
Excludes2

Care settingsHospice: not accepted as primary IPF Primary · MS-DRG 056–057

G91.4 (also written G914) is a billable ICD-10-CM diagnosis code for hydrocephalus in diseases classified elsewhere. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 7 codes in category G91 (Hydrocephalus). The Alphabetic Index lists it under 4 entries. Its coding notes include a Code first instruction, 4 Excludes1 entries and 8 Excludes2 entries.

Code first

If the underlying condition listed here is present and known, sequence it first.

This code

underlying condition, such as:
- congenital syphilis (A50.4-)
- neoplasm (C00-D49)
- plasminogen deficiency (E88.02)

Excludes1

Not coded here. The listed conditions generally should not be reported together.

This code

hydrocephalus due to congenital toxoplasmosis (P37.1)

Inherited from G91 Hydrocephalus

Arnold-Chiari syndrome with hydrocephalus (Q07.-)
congenital hydrocephalus (Q03.-)
spina bifida with hydrocephalus (Q05.-)

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Also from chapter/block level (8 notes)

Inherited from Chapter 6 Diseases of the nervous system

certain conditions originating in the perinatal period (P04-P96)
certain infectious and parasitic diseases (A00-B99)
complications of pregnancy, childbirth and the puerperium (O00-O9A)
congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
endocrine, nutritional and metabolic diseases (E00-E88)
injury, poisoning and certain other consequences of external causes (S00-T88)
neoplasms (C00-D49)
symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Care settings

How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.

Hospice: not accepted as primary

Not accepted as the principal diagnosis on a hospice claim (bill types 081x and 082x). The Integrated OCE returns an edit for this code.
Reason: Manifestation code. Report the underlying condition first (see the Code first note).

Source: CMS Integrated Outpatient Code Editor (IOCE) v27.3, effective October 1, 2026, edit 86

IPF Primary

IPF MS-DRG adjustment. A principal diagnosis of this code groups to one of these MS-DRGs. Which one depends on other facts of the stay, so the factor is a range:

MS-DRG	Description	Factor
056	Degenerative nervous system disorders w MCC	1.12
057	Degenerative nervous system disorders w/o MCC	1.11

A principal diagnosis that groups to none of the 19 designated MS-DRGs gets no MS-DRG adjustment. Otherwise the claim still receives the federal per diem base rate and the other adjustments.

Source: CMS IPF PPS FY 2027 final rule (CMS-1847-F), Addendum A; code lists from the CMS MS-DRG Definitions Manual v44; effective for discharges on or after October 1, 2026

Includes

Further defines or gives examples of the content of the category.

Inherited from G91 Hydrocephalus

acquired hydrocephalus

Alphabetic Index terms

Terms the official Alphabetic Index lists for this code. 4 entries