HYDROCEPHALUS
Hydrocephalus is the buildup of too much
cerebrospinal fluid in the brain. It was once known
as “water on the brain”. Normally, this fluid
cushions your brain. When you have too much, it
puts harmful pressure on your brain. There are two
kinds of hydrocephalus. Congenital hydrocephalus
is present at birth. Causes include genetic problems
and problems with how the fetus develops. An
unusually large head is the main sign of congenital
hydrocephalus. Acquired hydrocephalus can occur
at any age. Causes can include head injuries, strokes,
infections, tumors and bleeding in the brain.
Hydrocephalus can permanently damage the brain,
causing problems with physical and mental
development. If untreated, it is usually fatal. With
treatment, many people lead normal lives with few
limitations.
The Affects and Effects on the Visual System
Visual information is transmitted to the brain by the optic nerve, a cord that runs from the eye to
the brain. The meninges that surround the brain and spinal cord also surround the optic nerve.
Therefore increases in CSF pressure around the brain can also produce pressure on the optic
nerve. This pressure chokes off the supply of food and oxygen to the optic nerve, causing it to
swell. Swelling of the optic nerve due to hydrocephalus is called “papilledema.” The nerve can
be damaged through high CSF pressure or because of lower pressure elevation that lasts for a
prolonged time period. Damage to the optic nerve from papilledema can result in reduced vision,
reduced color vision, and visual field loss. Hydrocephalus produces different combinations of
signs and symptoms depending on its cause, which varies by age. In both children and adults, the
following may be signs of hydrocephalus: grayouts or fuzzouts of vision, double vision, reduced
vision, misaligned eyes, unstable or shaking eyes, or the “sunsetting sign” (the eyes pointed
downward with whites showing at top of eyes). In some patients with hydrocephalus, one or both
eyes will turn in or out (strabismus). They may also be unable to move their eyes to look up and
develop a retraction of the upper eyelids.
Treatments
The severity of hydrocephalus depends on the age at which the condition develops and the
course it follows. If the condition is well advanced at birth, major brain damage and physical
disabilities are likely. In less severe cases, with proper treatment, it's possible to have a nearly
normal life span and intelligence. The most common treatment for hydrocephalus is the surgical
insertion of a drainage system, called a shunt. It consists of a long flexible tube with a valve that
keeps fluid from the brain flowing in the right direction and at the proper rate. Another surgical
procedure that is sometimes used is a ventriculostomy. This is used when there's an obstruction
of flow between ventricles. In the procedure, the surgeon makes a hole in the bottom of one of
the ventricles, to allow the cerebrospinal fluid to flow toward the base of the brain, where normal
absorption occurs. Most hydrocephalic patients have normal vision, some patients develop poor
vision due to a weakness of the optic nerve or nerves know as optic-atrophy. This condition is
the result of dilatation in the third ventricle and the vision cannot be improved with eyeglasses,
although decompression of the third ventricle may sometimes result in a spontaneous
improvement of vision. Many hydrocephalic patients merely require glasses or corrective surgery
to straighten an eye that turns in or out.
Type of Condition
Hydrocephalus may be congenital or acquired. Congenital hydrocephalus is present at birth and
may be caused by either events or influences that occur during fetal development, or genetic
abnormalities. Acquired hydrocephalus develops at the time of birth or at some point afterward.
This type of hydrocephalus can affect individuals of all ages and may be caused by injury or
disease.
Anticipated Functional Implications
Hydrocephalus poses risks to both cognitive and physical development. However, many children
diagnosed with the disorder benefit from rehabilitation therapies and educational interventions
and go on to lead normal lives with few limitations. Treatment by an interdisciplinary team of
medical professionals, rehabilitation specialists, and educational experts is critical to a positive
outcome. Left untreated, progressive hydrocephalus may be fatal.
References
American Association of Neurological Surgeons. (2005, September). Hydrocephalus. Retrieved
from
http://www.aans.org/Patient%20Information/Conditions%20and%20Treatments/Hydroceph
alus.aspx
Alfano, Joseph. (n.d.). Eye findings in hydrocephalus. Retrieved from
http://nhfonline.org/articles.php?id=eyefindings
Better Medicine. (2011, May 2). Hydrocephalus. Retrieved from
http://www.bettermedicine.com/article/hydrocephalus
Mayo Clinic. (2009, September 12). Hydrocephalus. Retrieved from
http://www.mayoclinic.com/health/hydrocephalus/DS00393
National Institute of Health. (2011, June 23). Hydrocephalus fact sheet. Retrieved from
http://www.ninds.nih.gov/disorders/hydrocephalus/detail_hydrocephalus.htm