How is Hydrocephalus Treated in Holoprosencephaly?

When a child is diagnosed with holoprosencephaly (HPE), they may also develop hydrocephalus. Hydrocephalus happens when too much cerebrospinal fluid (CSF) builds up inside the brain. For parents hearing this diagnosis, it can be overwhelming, but there are established surgical ways to manage this buildup. The primary goal of treatment is to drain the extra fluid, which relieves pressure on the brain and prevents the head from growing too rapidly.

Understanding Hydrocephalus in HPE

In a typically developing brain, CSF flows through narrow pathways (ventricles) and is absorbed into the bloodstream. In children with HPE, the brain’s anatomy is different. Often, there is a large fluid-filled sac called a dorsal cyst that is connected to the ventricles ^[1]. Because of this unique structure, the fluid cannot drain normally, causing it to build up ^[1]. This buildup can lead to macrocephaly (an abnormally large head) as the fluid stretches the bones of the skull ^[2][3].

Ventriculoperitoneal (VP) Shunts

The most common treatment for hydrocephalus is a Ventriculoperitoneal (VP) shunt ^[1][4]. A shunt is a flexible medical tube placed under the skin.

• How it works: One end of the tube is carefully placed inside the fluid-filled spaces of the brain. The tube then runs under the skin, behind the ear, and down the neck into the peritoneal cavity (the space in the abdomen). Once the fluid reaches the belly, the body naturally absorbs it.
• The HPE Difference: In typical hydrocephalus, the tube goes into the brain’s main ventricles. For infants with alobar HPE and large dorsal cysts, neurosurgeons will often place the tip of the shunt directly into the dorsal cyst itself ^[1]. Research shows that shunting the dorsal cyst can improve comfort, overall outcomes, and developmental progress, even if the infant isn’t showing classic signs of high brain pressure ^[1]. Sometimes, programmable shunt valves are used so the doctor can adjust how fast the fluid drains without needing another surgery ^[4].

Unique Challenges for Children with HPE

Treating hydrocephalus in a child with HPE comes with specific challenges that your care team will help you manage:

• Skin Breakdown and Macrocephaly: Because hydrocephalus in HPE can cause the head to grow very large and heavy, infants are at a high risk for pressure injuries (skin breakdown or bedsores) on the back of the head, known as the occiput ^[5][2]. Preventing these sores is critical. It is recommended to reposition the baby’s head frequently—often at least every three hours—and use special pressure-relieving surfaces ^[6]. Never use hard objects to position your baby’s head ^[7]. Because standard safe-sleep guidelines emphasize a bare crib, ask your care team or a pediatric physical therapist about safe, medically approved devices (like specific medical gel pads) and how to safely support your baby’s delicate neck while turning them.
• Shunt Failure and Absorption Issues: Sometimes, the abdomen of a child with HPE struggles to absorb the cerebrospinal fluid, which can cause the VP shunt to fail ^[2]. If the VP shunt repeatedly fails because of this, surgeons might use an alternative called a Ventriculoatrial (VA) shunt, which drains the fluid into the heart instead of the belly ^[2].

Signs of Shunt Malfunction

VP shunts are life-saving, but they can malfunction if they get blocked, infected, or if the tubing disconnects. It is vital for parents to know the signs of a shunt malfunction, which is a medical emergency.

Watch for these classic signs:

• Unexplained vomiting or severe irritability ^[8]
• Lethargy (extreme sleepiness or difficulty waking up) ^[8]
• A tense or bulging soft spot (fontanelle) on the top of the head
• Fever (which may indicate a shunt infection)
• Swelling, redness, or thinning skin along the shunt tract (under the scalp or down the neck) ^[9]
• A noticeable or rapid increase in head size ^[8]

Keep in mind that children with complex anatomy might also show atypical signs of a failing shunt. For example, some children may experience changes in their vision without showing obvious changes on imaging tests (like a CT scan or MRI) ^[10].

What to do: If you suspect the shunt isn’t working right, contact your neurosurgery team immediately. If it is after hours, or if your child is experiencing severe symptoms like persistent vomiting, extreme lethargy, or a high fever, go directly to the nearest pediatric emergency room.

Moving Forward Together

Managing hydrocephalus requires ongoing vigilance, but you are not alone. By understanding how your baby’s shunt works and working closely with your neurosurgery and therapy teams, you can confidently protect their skin, monitor their health, and provide the supportive care they need to thrive.