ICD-10 Code G91.0 – Communicating Hydrocephalus (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G91.0 – Communicating hydrocephalus
What it is
Communicating hydrocephalus is a type of hydrocephalus in which cerebrospinal fluid flows through the ventricles but is not absorbed normally. Use this code when documentation identifies impaired CSF absorption without an obstructed ventricular pathway.
Clinical signs
Clinical features vary; refer to documentation. Common findings include enlarged ventricles on imaging and signs of increased intracranial pressure, such as headache, gait changes, or cognitive decline, depending on age and cause.
When to use this code
Use G91.0 when the provider documents communicating hydrocephalus, normal-pressure hydrocephalus, or hydrocephalus due to impaired CSF absorption. Code it when imaging and the assessment support this specific type rather than an obstructive form. If the record is unclear, check documentation.
Do not use for
Do not use this code for obstructive or noncommunicating hydrocephalus, or for ventricular enlargement without a documented diagnosis of hydrocephalus. Check documentation when the cause or type is not clearly stated.
Coding tip
Confirm the provider’s wording for the hydrocephalus type, because G91.0 depends on documented communication between the ventricles and subarachnoid space.