ICD-10-CM Alphabetic Index · FY 2026 34 Entries
Hydrocephalus in the ICD-10-CM Index ICD-10-CM
The main term Hydrocephalus (acquired) (external) (internal) (malignant) (recurrent) carries 34 index entries pointing to 22 ICD-10-CM codes. The default entry is G91.9, the code the bare main term maps to; every indented line below refines the term by site, cause, or type. Verify any candidate code in the Tabular List before using it.
✓ Built from the official CMS FY 2026 index fileEffective Oct 1, 2025 – Sep 30, 2026
34
Index Entries
22
Codes Referenced
G91.9
Default Code
H
Letter
34 of 34 shown
ICD-10-CM
Index Entries Under Hydrocephalus 34 entries · 22 codes
Hydrocephalus (acquired) (external) (internal) (malignant) (recurrent) G91.9
aqueduct Sylvius stricture Q03.0
causing disproportion O33.6 Non-billable
with obstructed labor O66.3
communicating G91.0
congenital (external) (internal) Q03.9
with spina bifida Q05.4
cervical Q05.0
dorsal Q05.1
lumbar Q05.2
lumbosacral Q05.2
sacral Q05.3
thoracic Q05.1
thoracolumbar Q05.1
specified NEC Q03.8
due to toxoplasmosis (congenital) P37.1
foramen Magendie block (acquired) G91.1
congenital Q03.1 see also Hydrocephalus, congenital
in (due to)
infectious disease NEC B89
neoplastic disease NEC (see also Neoplasm) G91.4
parasitic disease B89
newborn Q03.9
with spina bifida see Spina bifida, with hydrocephalus
noncommunicating G91.1
normal pressure G91.2
secondary G91.0
obstructive G91.1
otitic G93.2
post-traumatic NEC G91.3
secondary G91.4
post-traumatic G91.3
specified NEC G91.8
syphilitic, congenital A50.49
The info icon previews the code's description and billable status; the code link opens its full page with all notations.
Related Index Terms
Source: Centers for Medicare & Medicaid Services, FY 2026 ICD-10-CM Index to Diseases and Injuries release files, effective October 1, 2025 through September 30, 2026.
