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Hydrocephalus is a buildup of cerebrospinal fluid (CSF) in the brain. CSF is fluid that is made in the brain and surrounds the brain and spinal cord to cushion and support them. When there is a build-up of CSF, this can cause pressure on the brain, which can cause it to malfunction.
Like the hole at the center of a strawberry, inside the brain are four cavities called ventricles that are filled with CSF. Cerebral spinal fluid is made by a tissue within the ventricles called the choroid plexus. CSF is made constantly by the choroid plexus, like the kidneys constantly make urine.
The CSF circulates through the ventricles, down around the spinal cord, and over the surface of the brain. Once on the surface of the brain, CSF is reabsorbed back into the blood stream by special structures called the arachnoid villi.
The making, circulating, and reabsorbing of CSF is a constant and steady cycle. Any time there is a blockage of flow, a problem with re-absorption, or overproduction of CSF, the fluid builds up and hydrocephalus will result.
There are many causes of hydrocephalus. Some children are born with hydrocephalus and the exact cause is never known. Other times, the cause can be identified, such as when there is a physical blockage in the fluid cycle or an associated medical problem known to cause a blockage. Blockages can be congenital, meaning they are present at birth, or they can be caused by lesions such as brain tumors, infections or cysts. Hydrocephalus is also associated with certain birth defects such as spina bifida.
Problems with reabsorption can occur after such things as meningitis, bleeding in the brain or traumatic brain injuries. Over-production of CSF is very rare. It only occurs when there is a tumor in the choroid plexus.
Normal Pressure Hydrocephalus is a form of hydrocephalus that typically affects older adults.
Anyone can develop hydrocephalus. Children who are born with hydrocephalus (congenital) are often diagnosed before birth or during infancy. Given that hydrocephalus can result from so many different problems, children of all ages and adults can develop it.
The typical signs and symptoms of hydrocephalus are caused by increased pressure inside the brain and skull and can include progressively worsening headaches often with nausea and or vomiting. Other signs can include problems with balance, coordination, memory and blurred or “double” vision. Some children have behavioral changes or a marked decline in school performance.
Signs and symptoms of hydrocephalus can be quite different in infants and toddlers. Because the bones of the skull are not yet fused together in this age group, they may show no signs other than a rapidly increasing head size.
Adults with normal pressure hydrocephalus (a form of hydrocephalus that typically affects older adults) may have with balance disturbance, incontinence and dementia.
If hydrocephalus is expected based on your child’s history and symptoms, a brain imaging test must be done to determine if the fluid spaces inside the brain are enlarged.
In infants, a cranial ultrasound can be done to assess the fluid spaces. An ultrasound uses sound waves to look at structures inside the body. This study can only be done in infants with an open anterior fontanel (also known as a “soft spot”). It can identify whether or not hydrocephalus is present, but is often not sensitive enough to help determine the cause. Often a CT scan or MRI will also be necessary if hydrocephalus is present.
A CT, or CAT scan, stands for computed tomography. X-ray technology is used and manipulated to produce images of the brain. A CT scan is much more sensitive than ultrasound and can not only identify that hydrocephalus is present, but it can also help identify potential causes such as bleeding or tumors. A CT scan of the head is very quick, lasting just 1 to 2 minutes to obtain the information. Children typically do not need to fast or be sedated for this study.
An MRI (magnetic resonance imaging) uses a very powerful magnet to produce images of the brain. MRI is highly sensitive in identifying hydrocephalus and possible causes. It provides detailed information about the anatomy of the brain. Often, a person with hydrocephalus will undergo MRI imaging when they are diagnosed to help determine the cause. A full brain MRI is a much longer test than a CT, lasting at least 30 minutes, sometimes longer depending on the exact study. For a full MRI, it is important that the child does not move during the study – so many children will require sedation. A full MRI is not always needed to test for hydrocephalus.
Children with hydrocephalus often require frequent imaging tests to assess the status of their hydrocephalus treatment. In past years, this meant multiple CT scans. Because each CT scan exposes the child to a small dose of radiation, over a lifetime, those doses of radiation can add up.
Here at Children’s Colorado, we have the ability to do a quick MRI scan that provides all the necessary information in just 2 to 3 minutes. Children do not need sedation and will not get exposed to radiation. This study, called an MRI “shunt series,” is now the main study of choice in assessing patients with hydrocephalus. This special MRI is only available at Children’s Colorado, both on the main and North Campus.
Children displaying signs of symptoms of hydrocephalus will be seen by a neurosurgery doctor and undergo imaging tests. Your child’s doctor at Children’s Colorado will perform a thorough history and physical exam and will review the brain images from the tests.
The sophisticated neurological exam will show the signs and symptoms of hydrocephalus, and your child’s doctor will look for evidence of pressure on the brain and evaluate the size and anatomy of the ventricles.
The body will continue to produce cerebrospinal fluid (CSF) even when there is a buildup, which causes increasing pressure on the brain. Therefore, the treatment of hydrocephalus requires the creation of an alternative pathway for the CSF. In most cases, this involves the placement of a shunt.
A shunt is a narrow and flexible tube that allows the CSF to leave the brain and go somewhere else in the body to get reabsorbed, typically the peritoneal cavity (the place in the abdomen where organs such as the liver, stomach and intestines are housed). In the peritoneal cavity, the body makes and reabsorbs peritoneal fluid. The shunt lets the CSF to flow to the peritoneal cavity and get reabsorbed along with the peritoneal fluid.
In certain circumstances, a shunt can be avoided by using minimally invasive technology to create an alternative pathway for fluid, called an endoscopic third ventriculostomy (ETV). During this procedure, a small hole is made in one of the ventricles so that the CSF can bypass an obstruction. This procedure can only be used in certain types of hydrocephalus.
Children’s Colorado has by far the most depth and experience in managing the care of children with hydrocephalus, including six pediatric neurosurgeons and five pediatric neurosurgical pediatric nurse practitioners and physician assistants.
If your child has hydrocephalus, treating the condition individually and promptly can make all the difference. Our diagnostic tools and pediatric experience are unmatched at any other health care center in the region.
In addition, our very large Neurosciences group, including more than 20 neurologists, neurology nurse practitioners and developmental pediatricians allows for the most comprehensive and integrated care for even the most complicated cases of pediatric hydrocephalus.
Neurology - Pediatric