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G91.4

Hydrocephalus in diseases classified elsewhere

Billable FY2026 2025-10-01 → 2026-09-30
Exclusions 12 never code together
G91.4code
Excludes1
  • hydrocephalus due to congenital toxoplasmosis (P37.1)P37.1P37.1
G91code
Excludes1
  • Arnold-Chiari syndrome with hydrocephalus (Q07.-)Q07.-
  • congenital hydrocephalus (Q03.-)Q03.-
  • spina bifida with hydrocephalus (Q05.-)Q05.-
G00-G99chapter
Excludes2
  • certain conditions originating in the perinatal period (P04-P96)P04-P96
  • certain infectious and parasitic diseases (A00-B99)A00-B99
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)O00-O9A
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Q00-Q99
  • endocrine, nutritional and metabolic diseases (E00-E88)E00-E88
  • injury, poisoning and certain other consequences of external causes (S00-T88)S00-T88
  • neoplasms (C00-D49)C00-D49
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)R00-R94

Excludes1 — never code together. The excluded condition and this one are mutually exclusive.

Excludes2 — not included here, but the patient may have both. Code both when documented.

Instructional notes 5
G91code
Includes
  • acquired hydrocephalus
G91.4code
Code first
Index entries leading here 1
  • Hydrocephalus (acquired) (external) (internal) (malignant) (recurrent) G91.9
    • in (due to)
      • neoplastic disease NEC (see also Neoplasm) G91.4
    • secondary G91.4
Alongside this code 6 same parent — G91
Additional references
AHA Coding Clinic® Licence required

Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.

Risk adjustment

CMS28HCC127 ESRD21HCC51 ESRD24HCC51

Presence is a property of the code. Untick a model to hide it everywhere.

This code

Billable
yes
Code set
FY2026
Parent
G91
Block
G89-G99
Siblings
6

Present FY2024–FY2027.