- Acoustic neuroma (vestibular schwannoma)
- Acoustic neuroma (vestibular schwannoma) Open popup dialog
- Acoustic neuroma, also known as vestibular schwannoma, is a generally slow-growing, non-cancerous tumor that develops on the main nerve (vestibular) that leads from the inner ear to the brain. The branches of this nerve directly affect your balance and hearing, and the pressure of an acoustic neuroma can cause hearing loss, ringing in the ears, and instability.
Acoustic neuroma usually arises from Schwann cells that line this nerve and grow slowly or not at all. In rare cases, it can grow quickly and become large enough to press against the brain and interfere with vital functions.
The signs and symptoms of acoustic neuroma are often subtle and can take several years to develop. They’re usually the result of the tumor’s effects on hearing and nerve balance. The pressure of the tumor on nearby nerves that control facial muscles and sensations (facial and trigeminal nerves), nearby blood vessels, or brain structures can also cause problems.
As the tumor grows, it may be more likely that it is causing more noticeable or serious signs and symptoms.
Common signs and symptoms of acoustic neuroma include:
- Hearing loss, usually progressive – although in some cases sudden – and unilateral or more pronounced on one side
- Ringing (tinnitus) in the affected ear
- Instability, loss of balance
- Dizziness (dizziness)
The cause of acoustic neuromas appears to be a defective gene on chromosome 22. Usually this gene produces a tumor suppressor protein that helps control the growth of Schwann cells that line nerves.
What constitutes this genetic dysfunction is unclear and in most cases of acoustic neuroma there is no identifiable cause. This defective gene is also inherited from neurofibromatosis type 2, a rare disease in which tumors usually grow on the equilibrium nerves on either side of the head (bilateral vestibular schwannomas).
- utosomal dominant inheritance model
- Autosomal Dominant Inheritance PatternOpen Context Dialog
- Type 2 neurofibromatosis
- The only confirmed risk factor for acoustic neuroma is a parent with the rare genetic disorder neurofibromatosis type 2. However, neurofibromatosis type 2 only accounts for about 5% of cases of neurofibromatosis. Acoustically.
A distinctive feature of type 2 neurofibromatosis is the development of non-cancerous tumors on the equilibrium nerves on either side of the head, as well as on other nerves.
Neurofibromatosis type 2 (NF2) is known as an autosomal dominant disorder, which means that the mutation can only be passed on from one parent (dominant gene). Every child of an affected parent has a 50:50 chance of inheriting it.
An acoustic neuroma can cause a variety of lifelong complications, including:
- Hearing loss
- Numbness and weakness of the face
- Balance disorders
- Ring in your ear
- Large tumors can put pressure on your brain stem and prevent the normal flow of fluid between your brain and the spinal cord (cerebrospinal fluid). When this happens, fluid can build up in your head (hydrocephalus) and increase pressure in your skull.