G91.4
BillableHydrocephalus in diseases classified elsewhere
HCC Category Mapping
V28HCC 127 — Dementia, Mild or Unspecified
0.464What This Code Means
Hydrocephalus that develops as a secondary complication of another disease or condition, such as infection, hemorrhage, or malignancy.
Coding Tips
- •This code requires a secondary diagnosis code identifying the underlying disease causing the hydrocephalus
- •Use the 'in diseases classified elsewhere' convention and code the primary condition first
Clinical Significance
Hydrocephalus in diseases classified elsewhere is a manifestation code used when hydrocephalus develops secondary to another classified condition, such as neoplastic disease, infectious meningitis, or congenital toxoplasmosis. Proper sequencing requires the underlying disease to be coded first, making this a dependent code that reflects the complexity of multi-system disease management. Accurate capture is important for reflecting the true disease burden.
Documentation Requirements
- ✓Clear documentation of the underlying disease causing the hydrocephalus
- ✓Imaging confirming ventricular enlargement consistent with hydrocephalus
- ✓Clinical evidence linking the hydrocephalus to the underlying classified condition
- ✓Treatment status including any surgical intervention for the hydrocephalus
- ✓Current neurological status and impact on overall disease management
Excludes 1 — Do NOT code together
- hydrocephalus due to congenital toxoplasmosis (P37.1)
Code First
Commonly Confused Codes
G91.0 — Communicating hydrocephalus: use when hydrocephalus stands alone without an underlying classified conditionG91.1 — Obstructive hydrocephalus: use when the mechanism is obstruction and no underlying classified condition appliesG91.8 — Other hydrocephalus: for specified types not elsewhere classified without an underlying diseaseG91.9 — Hydrocephalus, unspecified: avoid when the type or cause is documented
Code Hierarchy
└G91Hydrocephalus└G91.4Hydrocephalus in diseases classified elsewhere
└G91.4Hydrocephalus in diseases classified elsewhere