Research Paper on "Neurofibroma and Anesthesiology"

Research Paper 15 pages (5537 words) Sources: 50

[EXCERPT] . . . .

Neurofibroma: Genetic Traits and Impact

Neurofibroma is an inheritable genetic condition whereby benign neural tumors (neurofibromas) form on the dermis, subcutaneous skin levels, in the brain and on the spinal cord.1 Neurofibroma possesses a high prevalence rate in terms of genetic transmission from parent to offspring. Generally, if one parent is a carrier for this condition, each offspring has better than a 50% probability of developing the disease.2 Aside from being inherited, Neurofibroma can be demonstrated in families with no genetic predisposition to the disease 3 This is the result of a genetic mutation is either gamete (sperm or egg). Specifically, this genetic anomaly is caused by the gene that regulates the expression and regulation of the protein nuerofibrin4. Like any genetic abnormality the results of the condition vary across individuals 5. Some of the common symptoms include large tumors under the skin, mild cognitive impairment, colored spots on the skin and possible long bone fractures, however this is more pronounced in young children 6

Neurofibroma is a disease that can impact individuals across a wide range of backgrounds. It is a disorder that can complicate pregnancy, adversely affect Cardiovascular and respiratory functions as well as cause thoracic deformities. The purpose of this analysis is to discuss in detail the background of Neurofibroma, from its genetic roots to its clinical manifestations. Additionally this analysis will focus on the impact Neurofibroma has on various bodily systems such as Respiratory, Cardiovascular and Thoracic. Furthermore, a review of the current pharmacology utilized in treating this disorder will be evaluated on the basis of efficacy and impact. Finally, this analysis will conclude with an overall assessment of the condition, a review of the effective treatments and an examination and the need for future research.

Analysis of Neurofibroma

Genetics of Neurofibroma and the protein Neurofibromin

The Neurofibroma Type 1 gene has been assigned the dubious distinction of having the highest number of mutations and irregularities of any gene within the Human Genome7 the NF-1 gene regulates the expression or deregulation of the protein Neurofibromin, which possesses certain tumor suppression qualities8 the incidence of NF-1 at birth is approximately 1 in 3500, displaying 100% penetrance. Although there is high penetrance, the phenotypic expression of NF-1 is quite variable10

NF-1 mutations lie along the NF gene, however there are 8 different exons and introns in which the mutations are expressed at a significantly higher frequency11 in these 8 regions of the NF-1 gene upwards of 41% of all the mutations are present. Recent studies11 have demonstrated there are other areas were mutations may develop. Accounting for the remaining mutations, 31% are predicated on frame-shift mutations, 9% are nonsense mutations; 8% are missense mutations and 2% are due to amino acid deletions12.

Mutations within the NF-1 gene can ultimately lead to negative consequences in terms of messenger-RNA processing and the protein Neurofibromin. Since the m-RNA is directly responsible for the correct coding and expression of the protein Neurofibromin-any mutations will negative impact protein expression. According to research13, 31% of mutations can lead to recurring mutations being expressed through Neurofibromin. There are over 1,000 variant mutations associated with NF-1 gene and its production of Neurofibromin. The two most common are mutations R304X which causes a frame-shift and allows exon 7 to be skipped whereas the second most common NF-1 mutation is Y2264X, that causes a nonsense mutation allowing exon 37 to be spliced from the genome14. These mutations provide the nexus for the various symptoms associated with Neurofibroma. Having the knowledge of the two most common mutations can drive researchers to examine these mutations, locate the regions within the chromosome where they are most likely to be found and derive treatments to suppress or reverse these mutations.

Clinical Presentation and Pathology

The phenotypic presentations of NF-1 can be divided into two categories: Tumor and non-tumor. The neurofibroma is the most prevalent tumor associated with neurofibromatosis. It is a mass consisting of Schwann cells, fibroblasts, perineurial cells and mast cells arising from peripheral nerves or nerve roots, either growing focally, or spreading length of the nerve15. If the growth includes nerve branches it is term a plexiform neurofibroma. Dermal or Cutaneous neurofibromas are skin tumor growths, which commence prepubertally or during pregnancy, can be found both either above or within the skin surface16. The prevalence of dermal neurofibromas is approximately 95% although the severity of this type of neurofibroma varies from patient to patient and cannot be predicted due to the varying genetic manifestation of the disease. Nodular neurofibromas originate in peripheral nerve but do not invade nearby tissue. Spinal neurofibromas, on the other hand cause spinal root compression can also invade the spinal canal to compress the spinal cord.

Plexiform neurofibromas are the classic sign of neurofibromatosis. Found in approximately 30% of NF1 patients, cause nerve compression as well as the attrition of surrounding structures such as bone. Although neurofibromas are typically benign, also there is a 10% chance of conversion to malignant peripheral nerve sheath tumors (MPNSTs). Conversion to MPNSTs usually originate from deep locations rather than superficial plexiform neurofibromas. Prognosis of NF1 derived MPNSTs is poor with a 5-year survival rate of approximately 21%. The best treatment of MPNSTs is surgery while radiation and chemotherapy have unclear success rates17.

Transformation of neurofibromas can affect the Central Nervous System. The most common CNS manifestation is the optic glioma. Optic gliomas symptomatically present themselves with visual field defects,, vision loss, or neuroendocrine abnormalities. It is unusual for optic gliomas to progress pass seven or eight-year of age. NF1 patients have an increased risk for malignant tumors such as leukemia, for example, acute myelomonocytic leukemia, as well as rhabdomyosarcoma, and pheochromocytoma. Forty six percent of patients develop Lisch nodules.

Non-tumor manifestations of the neurofibromatosis include skin pigmentation abnormalities, learning disabilities, skeletal and vascular dysplasias. Cafe-au-lait spots are hyperpigmented, flat and round areas of the skin that arise during infancy and increase throughout adulthood. Approximately 95% of NF1 patients have cafe-au-lait spots as adults18. Learning disabilities include difficulties with visuospatial construction, memory, and other cognitive skills. Vascular manifestation of the disease are rare, (approximately 1-3% incidence). Possible manifestations can include occlusions, stenosis, arteriovenous malformations, and fistulae.

Diagnosis

The standards for diagnosis of Neurofibroma have stood and withstood academic rigor. The broad standards for diagnosing Neurofibroma involve Cafe-au-lait spots, axillary freckling, Lisch nodes, distinct bony lesions and optic nerve gliomas. The manifestations of NF-1 are widespread and impact many bodily systems20. The skin spots and freckling do not normally cause implications; however some patients become distressed with these spots being present.

The main diagnostic indicator is the presence of Cutaneous Neurofibromas. These fibromas are found in the majority of NF-1 patients. These fibromas often exhibit a purplish tint at the outset. Furthermore the number of these fibromas vary among individuals and families. To date there have been no diagnostic evidence that indicates cutaneous fibromas undergo a malignant evolution.

One of the more potent and threatening conditions associated with NF-1 has an 8% to 13% probability over the lifespan of any NF-1 patient. Malignant Peripheral Nerve Sheath Tumors (MPNST) are difficult to detect and diagnose, metastasize quickly and offer a poor prognosis. Generally the diagnostic conditions associated with a MPNST include persistent pain in the fibromas that last for longer than thirty days, new or unexplained nerve deficits, hardening of the neurofibromas and an increase in the fibroma size. Individuals that develop these tumors more often than not possesses a high degree of cancer in their pedigree. Furthermore, these individuals may suffer from Optic pathway glioma, whole gene deletion, multiple subcutaneous neurofibromas or neurofibroma neuropathy.

Anesthetic Considerations

Dealing with Neurofibroma during surgery is a delicate balance. Various fibromas may present a variety of challenges for the medical team. Recently, a patient in the Taipei Veterans Hospital underwent a segmental resection of the trachea22. The patient was diagnosed as having Endotracheal Neurofibroma which caused significant airway blockage. Using a combination of mild anesthesia, fiberoptic bronchoscopy, intubation and extensive preoperative evaluations the patient's trachea was re-sectioned without incident.

The balance between surgery, anesthesia and neurofibromas becomes even more tenuous when considering if the patient is female and pregnant. In 2002, Dr. Amir 23 presented a case where a pregnant woman possesses an Inflammatory Myofibroblastic Tumor (IMT) that was blocking the upper trachea. The surgical path taken was to utilize a mild, local anesthetic so as to protect the unborn child. Once the patient was under anesthesia the IMT was excised without incident.

Another tumor-orientated offspring of Neurofibroma is referred to as Pheochromocytoma. A Phaechromocytoma arises in the neural cells most likely around the basal ganglia, vagus nerve and carotid arteries24. Hypertension is the most common symptom of patients with this type of tumor. Treatment involves tumor extraction. These tumors present a challenge for surgeons and anesthesiologists.

These tumors require preoperative, inter-operative and postoperative monitoring by physicians. The anesthesiologist must take a detailed history of the patient in order to determine the correct surgical path. During the surgery the anesthesiologist can employ several different techniques. General… READ MORE

How to Reference "Neurofibroma and Anesthesiology" Research Paper in a Bibliography

Related Research Papers:

Anesthesiology and Radiology Term Paper

Radiology/Anesthesiology

Two of the fields I am most interested in are anesthesiology and radiology. Each is attractive to me in its own way, and I look forward to being granted… read more

Term Paper 4 pages (1287 words) Sources: 5 Style: MLA Topic: Medicine / Pharmacy

---

Applying for Anesthesia Residency Research Proposal

Anesthesiology Residency Letter:

As I approach my fourth year of medical school, I have the privilege of seeking entry into a residency program to begin on September 1st, 2009. In… read more

Research Proposal 1 pages (385 words) Sources: 0 Topic: Nursing / Doctor / Physician

---

Scleroderma, a Chronic, Systemic Disease That Effects Term Paper

scleroderma, a chronic, systemic disease that effects the lungs, skin, heart, gastrointestinal tract, kidney and musculoskeletal system. The article is a case report on a specific case dealing with achalasia… read more

Term Paper 2 pages (608 words) Sources: 1 Topic: Nursing / Doctor / Physician

---

Helen Lamb on the Profession of Anesthesia Term Paper

Helen Lamb on the profession of anesthesia

Touted as one of the greatest medical discoveries for the 20th century, anesthesiology as a science has played a significant role in the… read more

Term Paper 6 pages (1531 words) Sources: 1+ Topic: Nursing / Doctor / Physician

---

Anesthesiologist Assistant Subspecialty Postgraduate Fellowship Term Paper

Subspecialty postgrad pain

As most of us are aware the U.S. population is aging at a never before seen rate, based on the availability of good medical care, proper nutrition… read more

Term Paper 6 pages (1837 words) Sources: 8 Style: APA Topic: Nursing / Doctor / Physician

---

View 100+ more related papers  >>