Bilateral Acoustic Neuroma

Bilateral Acoustic Neuroma
Bilateral Acoustic Neuroma

Overview Of Bilateral Acoustic Neuroma

A bilateral acoustic neuroma is a tumor on the nerve connecting the ear to the brain (vestibulocochlear nerve). An acoustic neuroma is benign, which means that it doesn’t spread to other, neighboring areas. However, it can still be dangerous, and damage several important nerves as it grows. Acoustic neuromas are fairly rare, and have been linked with the genetic disorder neurofibromatosis type 2 (NF2).

Commonly Associated With

  • Vestibular schwannoma
  • Tinnitus – acoustic
  • Cerebellopontine angle tumor
  • Tumor – acoustic
  • Angle tumor
  • Hearing loss – acoustic

Symptoms Of Bilateral Acoustic Neuroma

These can vary, depending on the location and size of the tumor. Because this type of tumor grows slowly, symptoms most often start after age 30.

Common symptoms include:

  • Abnormal feeling of movement (vertigo)
  • Hearing loss in the affected ear
  • Ringing (tinnitus) in the affected ear
  • Difficulty understanding speech
  • Dizziness
  • Headache
  • Loss of balance
  • Numbness in the face or one ear
  • Pain in the face or one ear
  • Weakness of the face or facial asymmetry

Exams & Tests

Often, the physical exam is normal, though the following signs may be present:

  • Unsteady walk
  • Decreased feeling on one side of the face
  • Drooping on one side of the face

The best way to identify a bilateral acoustic neuroma is with an MRI scan of the brain, but other tests to rule out other causes of dizziness/vertigo include:

  • Brainstem auditory evoked response (a test for Brainstem function and hearing)
  • Hearing test
  • Test of equilibrium and balance (electronystagmography or ENG)

Treatment Of Bilateral Acoustic Neuroma

Treatment depends on a number of factors, including: 

  •  the size and location of the tumor
  • your age
  • your overall health

You and your doctor will need to decide whether to remove the tumor, undergo radiation therapy to stop its growth  or watch the tumor without treatment. Most acoustic neuromas are very small, and since they grow so slowly, are often watched for changes, especially in elderly individuals. If the tumor is watched, then regular MRI scans will need to be done.

If not treated, some bilateral acoustic neuromas can:

  • Place pressure on nearby brain tissue
  • Lead to a buildup of fluid in the brain
  • Damage the nerves involved in hearing and balance
  • Harm the nerves responsible for movement/ feeling in the face, such as the trigeminal and craniofacial nerves

Removing an acoustic neuroma may be done for a number of reasons, such as:

Surgery or radiation therapy is necessary for removing the tumor, or neutralise it. Stereotactic radiosurgery isn’t actually surgery. It is a type of radiation therapy that focuses high-powered x-rays on a small area. It is used to slow down or prevent further growth of tumors that are hard to remove by surgical means. This is also the option for those unable to have surgery, such as immunocompromised patients, elderly people, and the very sick.

The type of surgery used to remove a bilateral acoustic neuroma is microsurgery. It involves the use of a high power microscope, and small tools, so precision is a must, as are steady hands! The goal of surgery is to safely remove the tumor, while damaging no nerves, and preserving at least some hearing. There is the risk, of course, that hearing is lost, or nerves are damaged. This is more likely to happen with large tumors.