Of all the articles in this library, this may be the most important to read and remember. Shunts can malfunction, and when they do, CSF can build up again — sometimes quickly. Recognizing the warning signs of a shunt malfunction allows prompt treatment, which can be life-saving. This isn't meant to frighten, but to empower.
Why shunts malfunction A shunt is a mechanical device, and like any device, it can develop problems. Common causes of malfunction include:
- Blockage (obstruction) — the most common issue; the catheter or valve can become blocked (for example, by tissue or debris), stopping the flow of CSF.
- Disconnection or breakage of the tubing.
- Migration — a component moving out of position.
- The shunt becoming inadequate as a child grows.
When a shunt malfunctions, it can no longer drain CSF properly, so fluid and pressure build up again — essentially causing the original hydrocephalus to return.
The key principle: return of original symptoms The most useful rule to remember is that a shunt malfunction often causes symptoms similar to the person's original hydrocephalus symptoms (or the classic symptoms of raised pressure). If the symptoms that led to the shunt come back, suspect a malfunction.
Warning signs in babies and infants. Watch for:
- Bulging or tense fontanelle (soft spot).
- Rapidly increasing head size.
- Vomiting.
- Irritability or a high-pitched cry.
- Excessive sleepiness or difficulty waking.
- Sunsetting eyes (eyes deviated downward).
- Poor feeding.
- Seizures.
Warning signs in children and adults. Watch for:
- Headache — often worsening, and classically worse in the morning.
- Nausea and vomiting.
- Drowsiness, lethargy, or difficulty waking.
- Vision changes — blurred or double vision.
- Balance or coordination problems.
- Irritability or behavioral/personality changes.
- Decline in school or work performance.
- Seizures.
- Redness or swelling along the shunt tract (which can suggest infection — see the infection article).
It can be gradual or sudden Some malfunctions cause gradual symptoms over days; others cause rapid deterioration. Rapid worsening — especially increasing drowsiness, severe headache with vomiting, or a change in alertness — is an emergency.
What to do If you suspect a shunt malfunction:
- For severe or rapidly worsening symptoms (intense headache, repeated vomiting, increasing drowsiness, vision changes, a change in responsiveness, or seizures), seek emergency care immediately.
- For milder but concerning symptoms, contact your (or your child's) neurosurgery team or doctor promptly for guidance.
- Always tell medical staff about the shunt, including its type and, if programmable, its setting. Bring any shunt information you have.
How malfunction is evaluated Doctors assess for shunt malfunction using examination, imaging (often a CT or fast MRI to check ventricle size, sometimes X-rays of the shunt tubing — a "shunt series" — to look for breaks or disconnections), and clinical judgment. If a malfunction is confirmed, treatment is usually shunt revision surgery (covered in its own article).
Know your normal People with shunts (and their families) often come to know their own typical pattern — and any deviation from it. Trust that knowledge. If something feels like the old symptoms returning, it's always appropriate to seek evaluation.
The empowering takeaway Shunt malfunctions happen, but they are manageable when recognized promptly. The single most important thing is to know the warning signs — especially the return of original symptoms — and to act quickly, seeking emergency care for severe or rapidly worsening symptoms. This knowledge is one of the most powerful tools you have for staying safe with a shunt.