ICD-10 Code G91.8 – Other hydrocephalus (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G91.8 – Other hydrocephalus
What it is
Other hydrocephalus refers to abnormal buildup of cerebrospinal fluid in the brain when the specific hydrocephalus type is not otherwise classified. Use this code for documented hydrocephalus that does not fit a more specific ICD-10-CM category.
Clinical signs
Clinical features vary; refer to documentation. Commonly, hydrocephalus is associated with enlarged ventricles on imaging and signs of increased intracranial pressure or neurologic change.
When to use this code
Use G91.8 when the provider documents hydrocephalus but does not specify obstructive, communicating, congenital, or another defined subtype. It also fits cases where the record states an atypical or unspecified form that is still clearly hydrocephalus. Check documentation if the note suggests a different, more specific code.
Do not use for
Do not use this code if the record identifies a more specific hydrocephalus type, such as congenital or obstructive hydrocephalus. If hydrocephalus is not confirmed, or the documentation is unclear, check documentation.
Coding tip
Look for the exact hydrocephalus subtype in the assessment and imaging report before defaulting to G91.8.