An acoustic neuroma is a benign non-cancerous growth, or tumour, in the brain. It's also known as a vestibular schwannoma.
An acoustic neuroma is a benign (non-cancerous) growth, or tumour, in the brain. It's also known as a vestibular schwannoma.
An acoustic neuroma grows on the vestibulocochlear nerve, which helps control hearing and balance. This nerve runs alongside the facial nerve, which carries information from the brain to the face muscles.
The symptoms of an acoustic neuroma tend to develop gradually and can vary in severity. This can make the condition difficult to diagnose (see below).
A small acoustic neuroma can lead to problems with:
- hearing – causing hearing loss or tinnitus (a noise perceived inside the ear but with no outside source)
- balance – causing vertigo (the sensation that you're spinning)
A large acoustic neuroma can cause a number of symptoms, including:
- headaches with blurred vision
- numbness or pain on one side of the face
- problems with limb co-ordination on one side of the body
Occasionally, large neuromas can also result in muscle weakness on one side of the face. In rare cases, it may also cause changes to the voice or difficulty swallowing (dysphagia).
What causes an acoustic neuroma?
The cause of most acoustic neuromas is unknown, but a small number of cases (about 5%) are caused by a rare, inherited condition called neurofibromatosis type 2.
Acoustic neuromas grow from the cells that cover the vestibulocochlear nerve, called Schwann cells.
Read more about the causes of an acoustic neuroma.
Diagnosing an acoustic neuroma
If your GP thinks you have an acoustic neuroma, you'll be referred to hospital for tests.
The three types of test you may have are:
Read more about how an acoustic neuroma is diagnosed.
Treating an acoustic neuroma
Acoustic neuromas tend to grow slowly and don't spread to other parts of the brain.
They can be so small and grow so slowly that they may not cause any symptoms or problems. In such cases, the acoustic neuroma may just be monitored to avoid risks associated with surgery.
In rare cases, the tumour can grow large enough to press on the brain. However, most acoustic neuromas can be treated before they reach this stage, either with surgery to remove the tumour or radiotherapy to destroy it.
Read more about treating an acoustic neuroma.
Complications of an acoustic neuroma
Acoustic neuromas aren't usually life-threatening but the symptoms can be disruptive. For example, the loss of hearing may affect your ability to communicate with others.
Speak to your GP or specialist if you feel the symptoms are having an impact on your day-to-day life. There may be ways of easing your symptoms, such as using a hearing aid or taking painkilling medication.
Read more about complications of an acoustic neuroma.
In most cases, the cause of an acoustic neuroma is unknown. The only known risk factor is having a very rare genetic condition called neurofibromatosis type 2.
In most cases, the cause of an acoustic neuroma is unknown.
The only known risk factor for developing an acoustic neuroma is having a rare genetic condition called neurofibromatosis type 2 (see below).
Acoustic neuromas grow from the Schwann cells lining the vestibulocochlear nerve, which is why they are sometimes called vestibular schwannomas. Schwann cells form a sheath around nerves, helping electrical signals to travel through the body.
It's also not known what causes some acoustic neuromas to start growing or continue growing while others remain the same size.
Neurofibromatosis type 2
A small number of acoustic neuroma cases (about 5%) are caused by a rare, inherited condition called neurofibromatosis type 2.
Neurofibromatosis type 2 causes benign (non-cancerous) tumours to grow on the nerve tissue in the body, in particular within the head cavity and spine. The condition is generally characterised by an acoustic neuroma on each side that's growing from both the left and right acoustic nerves.
Neurofibromatosis type 2 shouldn't be confused with neurofibromatosis type 1, which is much more common and can also cause benign spinal tumours. Neurofibromatosis type 1 affects the skin and doesn't cause acoustic neuromas.
In neurofibromatosis type 2 both acoustic nerves are usually affected. This means that you're more likely to have hearing loss in both ears. Therefore, it's important to address issues such as lip reading and sign language early on in case you lose hearing in both ears.
The symptoms of an acoustic neuroma can affect your day-to-life, but more serious complications are rare.
The symptoms of an acoustic neuroma can affect your day-to-day life, but more serious complications are rare.
Coping with your symptoms
Some symptoms of an acoustic neuroma can be difficult to live with and may affect your quality of life. For example, hearing impairment may have an impact on your job and communication may be more difficult. Severe dizziness and loss of balance may also affect your job and limit the activities you can do.
Speak to your GP or specialist if your acoustic neuroma is being monitored but you feel the symptoms are significantly affecting your daily life. There may be ways of easing your symptoms, such as using a hearing aid or painkilling medication, or you may need treatment to remove the tumour.
Occasionally, acoustic neuromas return after being removed. The tumours reoccur in less than five in every 100 people who have surgery to remove them.
It's likely that you'll need to have magnetic resonance imaging (MRI) scans over a number of years, regardless of which treatment you have.
One of the most serious complications of acoustic neuroma is a condition called hydrocephalus.
Hydrocephalus occurs when an acoustic neuroma is very large and presses on your brainstem (the lowest part of the brain that connects to the spinal cord).
This prevents the cerebrospinal fluid (CSF) from flowing between your brain and spinal cord. The blockage can cause pressure to build up inside your skull, which in turn puts pressure on the delicate tissues in your brain.
Hydrocephalus can be treated by draining away the excess CSF. It's important that it's treated quickly because in severe cases it can cause brain damage. In rare cases, hydrocephalus can be fatal.