ICD-10-CM > G00-G99 > G89-G99 > G91 > G91.4 G91.4 Hydrocephalus in diseases classified elsewhere Billable/Specific Copy Code Copy Description Code First underlying condition, such as:congenital syphilis (A50.4-)neoplasm (C00-D49)plasminogen deficiency (E88.02) Type 1 Excludes hydrocephalus due to congenital toxoplasmosis (P37.1)