Hydrocephalus literally means “water in the head.” The “water”—in this case—is actually cerebral spinal fluid (CSF). The brain is constantly producing CSF, which then circulates through the ventricles, the spinal cord, and the surface of the brain.
Why does hydrocephalus occur?
Generally, hydrocephalus is a result of the intraventricular hemorrhage (see previous post) or other injury or insult to the brain during the vulnerable neonatal period. This is a slow, gradual process that leads to ventricular enlargement. However, any imbalance in production, problems with reabsorption of fluid, or obstruction of flow can also cause a buildup of fluid within the ventricles. A baby’s head must proportionally grow to accommodate the extra fluid, and a head that is growing too fast can be the first indication of hydrocephalus. This enlargement can put pressure on the brain, leading to a variety of symptoms and possible complications.
How is it diagnosed?
While in the NICU, your baby’s head will be measured every week. If his head is growing too quickly, the doctor may order a cerebral ultrasound to check the size of the ventricles. If the ultrasound indicates that the baby does indeed have hydrocephalus, an MRI will most likely be ordered for a more detailed exam.
The following are the most common symptoms of hydrocephalus in babies:
A full or bulging fontanelle (soft spot located on top of your baby’s head)
Swelling or prominent scalp veins
Increasing head circumference
Seizures
Headache
Bulging eyes and eyes fixed downward (sunsetting eyes)
Increased irritability
High-pitched cry
Poor feeding
Episodes of apnea/bradycardia that resolve on their own
Projectile vomiting
Sleepiness or lethargy
How is it treated?
If the hydrocephalus is mild and your baby does not have any symptoms, the problem may resolve on its own. The doctor may simply keep a watchful eye on the head growth and repeat serial ultrasounds to ensure the problem isn’t getting any worse. If the hydrocephalus continues to evolve, treatment may be necessary.
Will my baby need a shunt?
If the cause of the hydrocephalus is determined to be a blockage, the excess CSF may be drained into the abdomen by a ventriculoperitoneal (VP) shunt. A highly skilled neurosurgeon places one end of a tiny, flexible tube into the enlarged ventricle, and the other end travels down into the baby’s abdomen. This allows the excess fluid to be reabsorbed into the bloodstream. The shunt usually runs behind the ear and the tubing is tunneled under the skin to the area of the abdomen. As your baby grows, he/she may need occasional shunt revisions or replacements, which is normal. Although they are very reliable, it is important to familiarize yourself with the signs of shunt malfunction.
Other forms of treatment include:
Placing an external ventricular drain (EVD). This is a type of shunt that is used to quickly decrease pressure in the ventricles and eliminate blood-filled CSF. Specifically, an EVD is placed to relieve intracranial pressure (ICP) and hydrocephalus when the normal flow of CSF around the brain is obstructed. A plastic tube is inserted in the ventricles to drain fluid and keep them decompressed (not swollen).
Frequent/weekly ventricular taps. This is when a needle is used to remove fluid directly from the ventricles, either free handed or with the help of an ultrasound. This is a short term option for infants with rapidly enlarging ventricles who cannot have a lumbar puncture due to contraindication.
Creating subcutaneous reservoirs (or ventricular access devices—VAD). These reservoirs are connected to a ventricular catheter that allows CSF drainage. The reservoir sits on the surface of the skull under the tissue that covers the top part of the brain. The reservoir can be punctured to withdraw CSF to keep the ventricular system decompressed.
Inserting a ventricular subgaleal shunt. Shunts have a tendency to malfunction in the presence of blood. This shunt is most frequently used as a temporary fix in the premature infant with hydrocephalus caused by a hemorrhage within the ventricle. A pocket in the brain is created between the skull and the scalp to allow CSF drainage. This allows the infant to mature and grow while awaiting placement of a permanent shunt.
What are the long-term effects?
Most children with hydrocephalus grow and develop right alongside their peers and have normal brain function. In some infants, however, hydrocephalus combined with other medical problems can create developmental challenges. These infants may be a little slower to reach developmental milestones and may need some assistance to help them achieve their full potential. It is important that development be monitored closely so that any problems are recognized and treated right away.
