Acoustic neuroma risk factors
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Simrat Sarai, M.D. [2]
Overview
Common risk factors in the development of acoustic neuroma are neurofibromatosis type 2, and low dose radiation.
Risk Factors
The risk factors of acoustic neuroma include:
Neurofibromatosis type 2
The known risk factor for acoustic neuroma is having a parent with the rare genetic disorder neurofibromatosis type 2. This disorder accounts for only a small number of cases. Neurofibromatosis type 2 is characterized by development of benign tumors on the VIII cranial nerve(balance nerves) on both sides of your head but it can affect other nerves too. NF2 is an autosomal dominant disorder. The mutation can be passed on by just one parent(dominant gene). Each child of an affcted parent has a 50% chance of inheriting it.
Radiation exposure
Childhood exposure to low-dose radiation of the head and neck may be associated with acoustic neuroma.
Acoustic neuromas may occur idiopathically (meaning the cause is unknown), however there is a growing body of evidence that sporadic defects in tumor suppressor genes may give rise to these tumors in some individuals. Other studies have hinted at exposure to loud noise on a consistent basis. One study has shown a relationship between acoustic neuromas and prior exposure to head and neck radiation, and a concomitant history of having had a parathyroid adenoma (tumor found in proximity to the thyroid gland controlling calcium metabolism). There are even controversies on hand held cellular phones. Whether or not the radiofrequency radiation has anything to do with acoustic neuroma formation, remains to be seen. To date, no environmental factor (such as cell phones or diet) has been scientifically proven to cause these tumors. The Acoustic Neuroma Association (ANA) does recommend that frequent cellular phone users use a hands free device to enable separation of the device from the head.[13]
Although there is an inheritable condition called Neurofibromatosis Type 2 (NF2) which can lead to acoustic neuroma formation in some people, most acoustic neuromas occur spontaneously without any evidence of family history (95%).[14] NF2 occurs with a frequency of 1 in 30,000 to 1 in 50,000 births. The hallmark of this disorder is bilateral acoustic neuromas (an acoustic neuroma on both sides). This creates the possibility of complete deafness if the tumors are left to grow unchecked. Preventing or treating the complete deafness that may befall individuals with NF2 requires complex decision making. The trend at most academic U.S. medical centers is to recommend treatment for the smallest tumor which has the best chance of preserving hearing. If this goal is successful, then treatment can also be offered for the remaining tumor. If hearing is not preserved at the initial treatment, then usually the second tumor, in the only-hearing ear, is just observed. If it shows continued growth and becomes life-threatening, or if the hearing is lost over time as the tumor grows, then treatment is undertaken. This strategy has the highest chance of preserving hearing for the longest time possible.