Obstructive hydrocephalus

This code represents a form of hydrocephalus where the flow of cerebrospinal fluid (CSF) is blocked within the ventricular system or at its outlets, leading to an accumulation of CSF and increased intracranial pressure. This obstruction can be caused by various factors such as tumors, congenital malformations, or inflammation.

Apply this code when documentation clearly indicates a blockage in CSF flow, distinguishing it from communicating hydrocephalus. Supporting documentation should specify the presence of an obstruction and its anatomical location, if known. This code is appropriate for both acute and chronic presentations of obstructive hydrocephalus.

• Differentiate carefully between obstructive (non-communicating) and communicating hydrocephalus; the latter is coded elsewhere.
• Always sequence this code as a primary diagnosis when it is the reason for the encounter, unless a more specific underlying cause is being treated.
• Look for documentation of specific causes of obstruction (e.g., tumor, aqueductal stenosis) and code them additionally to provide a complete clinical picture.