Achondroplasia (cont.)
How is achondroplasia diagnosed?
The diagnosis of achondroplasia can be based on the
typical physical features, the hallmarks of achondroplasia, evident at birth.
Characteristic features are also seen by radiology (X-ray), ultrasound, and other imaging
techniques. With ultrasound, the diagnosis can sometimes be strongly suspected
before birth.
The molecular diagnosis of achondroplasia before birth is possible if there
is suspicion of the diagnosis or an increased risk (such as when a parent is
affected by achondroplasia). In families in which both parents have
achondroplasia, prenatal diagnosis may be particularly useful, the aim being to
distinguish fatal homozygous achondroplasia from heterozygous
achondroplasia (with one copy of the achondroplasia gene) from normal. Diagnosis
before birth is accomplished by examining cells obtained by
chorionic villus
sampling (CVS) or amniocentesis.
What can be done for patients with achondroplasia?
Children and adults with achondroplasia can lead normal
lives provided they receive attentive, informed care by their physicians and
parents. Considerations in monitoring children with achondroplasia include
careful measurements of growth (length/height and weight) and head circumference
using curves specially standardized for those with achondroplasia. Knowledgeable
pediatric care and
periodic orthopedic and neurologic examinations are critical.
When special problems complicate achondroplasia, prompt
and expert intervention is important. For example:
- The foramen magnum (the
large opening under the skull) may need to be surgically enlarged in cases of severe narrowing
(stenosis) and
compression of the
spinal cord.
- The back of patients with
achondroplasia can develop a marked sway (lordosis) to the lower back while
abnormalities in the mid-back may cause a small hump (kyphosis) in infancy and
compression of the spinal cord in adolescence. The
spinal cord compression can require surgery to decompress it.
- Orthopedic procedures may
be performed for lengthening of the limb bones and correction of bowed legs (usually after full
growth has been achieved).
- Surgery (lumbar laminectomy) is also
indicated when spinal stenosis (narrowing) causes symptoms, which tends to be evident in young
adults.
- Disproportion between the brain and the base of the skull can sometimes
result in hydrocephalus ("water
on the brain") which needs to be promptly detected and treated by placement of a
shunt to drain the excess fluid.
- The large head with achondroplasia increases the chance of bleeding within
the baby's head during vaginal delivery. This should be taken into account in
planning the birth and postnatal care. The
brainstem (which
contains a center for controlling respiration) may be compressed in
achondroplasia and contribute to abnormal breathing.
- Pregnant women with achondroplasia should have their babies delivered by
cesarean section, due to their characteristically small
pelvis, and high risk of
birth related trauma.
- Middle ear infections are frequent and can lead to mild
to moderate hearing loss. Therefore, ear infections should be readily suspected
and promptly and fully treated with antibiotics or
ear tubes.
- Dental crowding is also common.
Teeth should be straightened and, if necessary, removed to alleviate this
problem.
- Control of obesity is essential. The child with
achondroplasia must not be allowed to become overweight. Adults with
achondroplasia should also monitor and control their weight because excess
weight aggravates back and joint problems.
- Treatment with human growth hormone, which is still considered experimental,
has been preliminarily reported to increase the growth rate after treatment, but
studies have not yet demonstrated that adult height is increased by this
treatment.
Next: How is achondroplasia inherited? »
- Ultrasound - Learn an ultrasound procedure, and conditions and diseases it assists in diagnosing and screening like tumors, cysts, heart conditions and more.
- Hydrocephalus - Learn about hydrocephalus (water on the brain) causes like brain trauma, stroke, infection, tumor, and more.
- Ear Tubes - Learn about ear tubes (myringotomy), a procedure that allows ventilation in the middle ear. Pre-surgery, during surgery, post surgery, and follow-up information is included.
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