Spina
Bifida
What
is it?
Spina
bifida is the common name for a range of birth
defects caused by problems with the early
development of the spine. It
is a condition in which part of one or more
vertebrae fails to develop completely, leaving a
portion of the spinal cord unprotected.
Who
gets it?
Spina
bifida occurs in one of every 700 births to whites
in North America, but in only one in every 3,000
births to African-Americans.
What
causes it?
Spina
bifida is a neural tube defect. The neural tube
forms during fetal development and eventually
becomes the spinal cord and the brain. Spina
bifida occurs within the first three to four weeks
of pregnancy when an embryo’s spinal neural tube
doesn’t close completely. Spina bifida has been
linked to environmental factors in some areas, to
a lack of folic acid during pregnancy, and to
certain medications, such as valproic acid, taken
during pregnancy.
What
are the symptoms?
The
symptoms of spina bifida vary depending upon how
severely the spinal cord and the surrounding
nerves are affected.
In the most common form, spinal bifida occulta, one or more vertebrae do not form
normally, but the spinal cord and the layers of
tissue surrounding it (the meninges) do not
protrude. Instead
there may be a dimpled or pigmented area over the
defect. In
a more severe form, called a meningocele, a
fluid-filled bulge that
includes the meninges protrudes through the
incompletely formed vertebrae. The most severe
form of spina bifida is a myelocele.
With this form, the meninges and some part
of the spinal cord actually protrude through the
opening in the spine. Often, the spinal cord
itself has not developed properly. In
some cases, the entire length of the spine may be
open, which is called rachischisis. Rachischisis
often results in death from infection or the
severity of function that is lost. The higher up
in the spine the defect occurs, the more severe
the disabilities.
Most patients will demonstrate symptoms in the legs ranging
from general weakness to complete paralysis.
Other complications include severe problems with bladder and
bowel function, water on the brain
(hydrocephalus), clubfeet and hip dislocations,
and abnormal curves and bends in the spine (kyphosis
and scoliosis).
The effect on a child’s intellect ranges
from none to extreme intellectual deficiencies,
depending upon the severity of the spinal defect
and the presence of hydrocephalus.
It is important to note that children with spina bifida often
are highly sensitive to latex.
Allergic reactions to latex can range from
a minor skin rash to difficulty breathing.
Severe reactions can be life threatening.
How
is it diagnosed?
Spinal
bifida is diagnosed by observation of the
protruding sac at birth. However,
some infants may have only a light dimple at the
base of the spine.
Other signs include a port wine stain
birthmark along the spine, areas of hair growth in
area of the spine, muscle weakness, poor reflexes,
and poor muscle tone in the anal sphincter.
In cases where spina bifida is not obvious
but is suspected, your physician may order spinal
x rays, computed tomography scans
(CT scans), and an ultrasound examination of the
spinal area. Another
procedure used frequently is called myelography.
After a dye is injected into the area
surrounding the spinal cord, an x-ray or CT scan
gives a more accurate picture of the spine. Spina
bifida can often be diagnosed before birth.
During the 16th to 18th week of pregnancy,
an alpha-fetoprotein (AFP) test can identify
neural tube defects in the fetus.
If AFP levels are abnormally high, other
tests such as amniocentesis and ultrasound
examination can confirm a neural tube defect with
an over 90% accuracy rate. Having
this information during the pregnancy can give
parents valuable time to make decisions and to
prepare for a child with significant medical
needs.
What
is the treatment?
Treatment
of spina bifida begins with closing the spinal
opening. Additional
treatment may be needed for related conditions
such as hip dislocations, clubfeet, kyphosis, or
scoliosis. When
hydrocephalus is present, drainage tubes (shunts)
can prevent brain damage from cerebrospinal fluid
and have been shown to improve verbal and visual
memory, motor coordination, and other cognitive
functions. Children
with spina bifida generally experience a delay in
walking, and will usually require braces.
If the bladder is affected, a catheter is
used to ensure the bladder is completely emptied. Physical therapy helps keep joints more flexible and
strengthens muscles.
Self-care
tips
Women
who take folic acid supplements before and during
pregnancy significantly lower their risk of having
a baby with a neural tube defect. Some studies
have indicated that just 0.4 mg of folic acid a
day decreases the risk of spina bifida by up to
75%. Because
the defect that causes spina bifida occurs so
early in pregnancy, the medical community
recommends that women who are considering
pregnancy should immediately begin taking a folic
acid supplement. Women
should avoid medications containing valproic acid
during pregnancy.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
|
