Achondroplasia
Instructions:
1) Describe pt. history and symptom
2) Describe patient’s population affected , frequency
3) Advantage and disadvantage over other modalities
4) Describe of modality used including view , positioning , techniques.
5) Review of image findings( can include other supporting test such as lab, etc
6) Diagnosis and discussion of pathology
7) Treatment option
8) prognosis
9) Reference( using APA format)
Solution
Achondroplasia
Introduction
Achondroplasia is a form of unsymmetrical dwarfism whereby one has a torso of normal size but with short arms and legs. Dwarfism refers to a restricted growth that is brought about by a bone disorder which causes one to have a condition of short stature as an adult. Other problems that come with this condition include protruding forehead, megalencephaly, congenital facial anomaly and thoracolumbar gibbus or arched back. There are many forms of dwarfism and the most common type of unsymmetrical dwarfism is achondroplasia. While most cases are as a result of spontaneous mutation of genes, some of them are hereditary.
Patient’s History and Symptom
A baby boy was delivered normally but the physical examination showed that he had an abnormally big head short arms and legs and mid face hypoplasia. The father of the baby has a normal height while the mother is of below average height and prenatal tests for achondroplasia were not done. The mother is not an abuser of drug and alcohol and took the appropriate vitamins while she was pregnant. Other symptoms that were noticed include spinal curvature, bowlegged deformity and weak muscle tone.
Prevalence and Populations Affected
Achondroplasia can occur in one out of 15,000 or 40,000 births. It has been discovered that older parents have a higher risk of having children with the condition compared to younger ones. Therefore, as the partenal age increases, the risk also increases. If one parent has achondroplasia there is a 50% chance that the baby will have the condition. If both parents have it, the chance of having a child with achondroplasia is 50%, the chance of having a child without the condition is 25% and the chance of having a child with homozygous achondroplasia is 25%(Khan, & Chew, 2015). Homozygous achondroplasia is a condition where the child inherits the gene mutation from both parents.
Advantage and disadvantage over other modalities
The modalities used in diagnosis of Achondroplasia include antenatal ultrasonographyto detect skeletal dysplasia, computed tomography (CT) scanning, magnetic resonance imaging (MRI) and genetic testing. Antenatal ultrasonography is preferred in investigation of pregnancies at risk while radiography is mostly used in adults and children. Magnetic resonance, CT scanning, and MRI are advantageous when symptoms of achondroplasia have been seen. MRI also depicts posterior cranial fossa anatomy(Khan, & Chew, 2015). CT scanning and MRI are the best modalities that are used to examine foramen magnum size. Radiology is used when the head size increases disproportionately. Ultrasonography is also used in examining ventricles in infants. However these modalities also have limitations. For instance, ultrasonography may provide false results; myelography is an invasive procedure and CT scanning results in patients being exposed to ionizing radiation. MRI is costly and may cause problems in claustrophobia patients and in patients with surgical foreign objects in their bodies(Ornitz, & Legeai-Mallet, 2017).
Modality used In Viewing and Positioning
Modalities used in viewing include radiology is used in skeletal survey to identify dysplasia. It may also be used in determining the maturity of bones in hands and wrists. MRI is also used in imaging in patients with hypopituitarism to scan the brain (Khan, & Chew, 2015).
Review of image findings
Lab analysis of plasma can be done in the mother to determine the presence of FGFR3 mutation. This is done if prenatal ultrasonography indicates the presence of short-limb skeletal dysplasia. DNA tests can also be done if both parents are affected to determine if infants have inherited the affected genes from both parents(Ornitz, & Legeai-Mallet, 2017).
Treatment
Treatments include growth hormone therapy which is used in improving the patients’ heights. Administration of parathyroid hormone also cures the retarded skeletal development. There are also several surgical therapies that may be used (Ornitz, & Legeai-Mallet, 2017). They includesurgical limb-lengthening procedures, spinal canal decompression to treat spinal and double leg lengthening surgery.
Prognosis
Prognosis is dependent on the severity of the condition because patients with the homozygous achondroplasia die as infants. Those with heterozygous achondroplasia survive and have normal life span.
Conclusion
Although achondroplasia is mostly caused by
spontaneous gene mutations, it can also be hereditary. If an infant has
homozygous achondroplasia, there are high chances it will die two weeks after
birth. Achondroplasia is a rare condition since it occurs in one out of 15,000
to 40,000 live births. Modalities used in diagnosis include MRI, CT scanning,
radiology and ultrasonography. Lab ananyses of plasma and DNA tests can be used
to confirm image findings. Growth hormone and surgical therapies are the
treatment options for the disease.
References
Khan, A., & Chew, F. (2015). Achondroplasia Imaging: Overview, Radiography, Computed Tomography. Emedicine.medscape.com. Retrieved 18 March 2017, from http://emedicine.medscape.com/article/415494-overview
Ornitz, D., & Legeai-Mallet, L. (2017). Achondroplasia: Development, pathogenesis, and therapy. Developmental Dynamics, 246(4), 291-309. Retrieved 18 March 2017 from http://onlinelibrary.wiley.com/doi/10.1002/dvdy.24479/full