EVER heard of hydrocephalus? The Merck Manual of Medical Information lists it as one of the 7 most common brain defects, particularly among newly-born children.
In fact, it is one of the most common birth defects, afflicting more than 10,000 babies each year.
Studies by the Geneva-based World Health Organization (WHO) show that one birth in every 2,000 results in hydrocephalus.
Also known as “water on the brain,” the term hydrocephalus is derived from two words: hydro for water and cephalus for head. But one authority observed that “water on the brain” is a misnomer.
He explains: “In reality, most cases of hydrocephalus represent a build up of spinal fluid inside the brain.
Everyone produces spinal fluid inside their brains every minute of their lives. This fluid is very similar to the liquid portion of blood and contains various salts and products such as sodium and glucose.
The fluid is primarily produced in connected chambers within the brain known as ventricles. The fluid volume produced in an adult is about equal to one pint per day.”
He continues: “This fluid then circulates through the ventricles and around the brain and spinal cord. Eventually it is reabsorbed over the surface of the brain into large veins which carry the fluid back to the heart.
This orderly cycle of spinal fluid production, flow and absorption maintains a protective environment to the nervous system. In addition, there is no loss of fluids or the salts contained in the spinal fluid.”
Hydrocephalus takes place when “something has occurred to prevent this orderly procession of events.”
While many hydrocephalus cases have no clear cause, there are several reasons why cerebrospinal fluid (CSF) – water-like fluid produced in the brain that circulates around and protects the brain and spinal cord – fails to drain into the bloodstream. Among these are:
Congenital hydrocephalus. This means that hydrocephalus is present at birth. It is important to remember that this term does not imply that it is hereditary. Often the exact cause of congenital hydrocephalus cannot be determined.
Prematurity. Babies born prematurely are at risk of developing hydrocephalus, according to medical experts.
A baby born early is far more vulnerable than one which goes the full term since many parts of the body will not have matured; for example, the brain is still in a very active stage of development.
Spina bifida. This is a condition in which part of one or more vertebrae fails to develop completely, leaving a portion of the spinal cord unprotected.
Recent studies have shown that the majority of babies born with spina bifida (70-90 percent) have hydrocephalus. Ninety to 95 percent of babies with spina bifida and related defects are born to parents with no family history of these disorders.
Meningitis. This is an infection of the membranes covering the brain. The inflammation and debris from this infection might block the drainage pathways resulting in hydrocephalus. Meningitis can occur at any age.
Tumors. These can be benign or malignant. Tumors of the brain cause compression and swelling of surrounding tissues, resulting in poor drainage of CSF.
In the treatment of brain tumors, it is often necessary to include measures to control hydrocephalus, which might only be temporary.
There are many other very rare causes of hydrocephalus. There is a particular group of disorders involving the formation of fluid filled cysts (for example, Dandy-Walker cyst) in the CSF system.
In these cases, hydrocephalus is often due to pressure on the surrounding tissues by the enlarging cyst.
In early infancy, hydrocephalus is usually detected by the family or pediatrician as a rapidly enlarging head.
This may or may not be associated with symptoms such as vomiting, failure to thrive, irritability, delay or loss of developmental milestones. Later in infancy and into childhood, there are rarely rapid changes in head size, but rather symptoms as described earlier.
What are the most common problems associated with hydrocephalus? The Hydrocephalus Foundation, Inc. cites the following:
Visual: Visual impairments that influence the upward gaze and ocular movement affect 25-33 percent of children with hydrocephalus. Depth perception is also a common visual impairment.
Motor skills: As many as 75 percent of children with hydrocephalus have some form of motor disability.
An individual with a shunt can participate in most physical activities. However, he/she is advised to stay away from rough contact spots, particularly those that inquire the use of a helmet.
Some other physical complications that are sometimes associated with hydrocephalus are the sensitivity to pressure, sound, and bright lights.
Side effects such as seizures, constipation, and hormonal imbalance can also be associated with hydrocephalus.
Learning disabilities: These are the most common complications for people with hydrocephalus. Individuals are able to learn. However, they may require modifications to do so.
Two-thirds of children with hydrocephalus do have at least normal or borderline intelligence. A problem related to learning disabilities is the inability or deficiency in memory retention.
Some forms of hydrocephalus require no specific treatment. Other forms are temporary and do not require long-term treatment. However, most forms do require to be treated, and this is usually done surgically.
Drugs have been used for many years but they may have unpleasant side effects and are not always successful.
It is important to realize that while hydrocephalus is very treatable, the underlying cause may not be or may have caused irreversible damage to the brain.
It is important for the doctors taking care of a child with hydrocephalus to determine if the problem is ongoing or if it has resolved but left enlarged but stable ventricles.
This can sometimes be difficult to tell and often the decision will be based on many factors including symptoms, eye exams, and changes in level of activity or school performance.
And now the good news. Over the past 25 years, death rates associated with hydrocephalus have decreased from 54 percent to five percent; intellectual disability has decreased from 62 to 30 percent.
