Shunt obstruction (blockage)

What it is

Shunt obstruction is a blockage somewhere in the shunt system that prevents cerebrospinal fluid from flowing properly. It is the most common cause of shunt malfunction.

Understanding Shunt obstruction (blockage)

A shunt can become obstructed at different points: the proximal (ventricular) catheter, the valve, or the distal catheter. Proximal catheter obstruction — for example, by choroid plexus, debris, or cells blocking the catheter's holes — is the most common single cause of shunt failure. When a shunt is obstructed, CSF builds up again, causing symptoms of raised pressure. Obstruction is diagnosed through evaluation and imaging (such as assessing ventricle size and, sometimes, a shunt series or shuntogram) and is treated with a shunt revision to clear or replace the blocked component. Understanding that obstruction is the leading cause of malfunction helps explain why shunt problems occur and why revisions are sometimes needed.

Why it matters

Understanding shunt obstruction helps families see why shunts can stop working — most often from a blockage — and why a revision is used to restore flow when obstruction causes a malfunction.