Hydrocephalus is one of the most frequently seen problems in a pediatric neurosurgical department. Hydrocephalus is frequently referred to as “water on the brain” but it is actually more like a build-up of cerebral spinal fluid inside the brain.
Our brain is constantly producing a fluid called CSF or cerebrospinal fluid. CSF flows around the brain and spine. A certain amount of fluid is reabsorbed by the brain but the remaining CSF will travel through the ventricle to the fourth ventricle at the base of the brain where it will exit.
Hydrocephalus happens when something has occurred to prevent the flow of the CSF. When this occurs, there is a build-up of spinal fluid in the brain, which can lead to injury or even death if not treated.
What causes hydrocephalus?
Hydrocephalus usually results either from:
- An imbalance between CSF production and absorption (communicating hydrocephalus). This is often seen with meningitis and subarachnoid hemorrhages
- A blockage within the ventricular system, such as a tumour, that prevents CSF from circulating (obstructive hydrocephalus)
While many cases have no clear cause, the following have been associated with the development of hydrocephalus: bleeding, infection, trauma, tumours, vascular problems and structural problems.
What are the symptoms of hydrocephalus?
Hydrocephalus is commonly diagnosed in utero by ultrasound or fetal MRI. For babies, pediatricians or public health nurses may identify a rapidly enlarging head circumference or full fontanelle (soft spot), the infant may or may not have symptoms such as vomiting, failure to thrive, irritability and delay in meeting developmental milestones.
Older children with hydrocephalus will most likely be associated with a trauma or brain tumour. Symptoms include severe headache, nausea, vomiting and decreased level of consciousness.
How is hydrocephalus diagnosed?
Either a CT scan or MRI scan can be used to diagnose hydrocephalus. Neurosurgeons may choose to order an MRI scan because this scan offers more detailed pictures which may help identify the possible cause of the hydrocephalus.
View CSF shunt section (page 41) to see what hydrocephalus looks like on an MRI, CT and FISP scan.
Treatment of hydrocephalus
If progressive hydrocephalus is diagnosed, almost all cases require surgery.
If there is a mass in the brain, such as a tumour or cyst that is disrupting the flow, it is sometimes possible to remove the mass and allow for normal flow of the CSF. If the blockage cannot be removed, a shunt may need to be inserted to help move the fluid out of the ventricle to other sites of the body, such as the abdomen, chest or heart. The most common operation is a ventriculoperitoneal shunt.
Another common operation used in many pediatric neurosurgical centres is an endoscopic third ventriculostomy (ETV).
An ETV is a hole that is created in the floor of the third ventricle, like creating a new drain in the bottom of a plugged sink. This procedure is most successful in older children with non-communicating hydrocephalus. The advantage of this procedure is it may avoid the implantation of a foreign body. Like a shunt, however, there is also a chance that the ETV can seal over and the hydrocephalic patient may become symptomatic again.
FAMILY EXPERIENCE: “I remember sitting in the community health clinic and the nurse being worried as she looked at my son’s head measurement and plotted it on the head growth chart. His head size was going up so quickly. I knew something was wrong.”