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| Acoustic neuroma by Pharmacytimess |
Acoustic
neuroma
Overview
Acoustic neuroma, also known as vestibular
schwannoma, is a noncancerous and usually slow-growing tumor that develops on
the main (vestibular) nerve leading from your inner ear to your brain. Branches
of this nerve directly influence your balance and hearing, and pressure from an
acoustic neuroma can cause hearing loss, ringing in your ear and unsteadiness.
Acoustic neuroma usually arises from the
Schwann cells covering this nerve and grows slowly or not at all. Rarely, it
may grow rapidly and become large enough to press against the brain and
interfere with vital functions.
Treatments for acoustic neuroma include
regular monitoring, radiation and surgical removal.
Symptoms
Signs and symptoms of acoustic neuroma are often
easy to miss and may take many years to develop. They usually happen because of
the tumor's effects on the hearing and balance nerves. Pressure from the tumor
on nearby nerves controlling facial muscles and sensation (facial and
trigeminal nerves), nearby blood vessels, or brain structures may also cause
problems.
As the tumor grows, it may cause more
noticeable or severe signs and symptoms.
Common signs and symptoms of acoustic neuroma
include:
·
Hearing loss, usually
gradually worsening over months to years — although in rare cases sudden — and
occurring on only one side or more severe on one side
·
Ringing (tinnitus) in
the affected ear
·
Unsteadiness or loss
of balance
·
Dizziness (vertigo)
·
Facial numbness and
weakness or loss of muscle movement
In rare cases, an acoustic neuroma may grow
large enough to compress the brainstem and become life-threatening.
When to see your
doctor
See your doctor if you notice hearing loss in
one ear, ringing in your ear or trouble with your balance.
Early diagnosis of an acoustic neuroma may
help keep the tumor from growing large enough to cause serious consequences,
such as total hearing loss.
Causes
The cause of acoustic neuromas can be linked
to a problem with a gene on chromosome 22. Normally, this gene produces a tumor
suppressor protein that helps control the growth of Schwann cells covering the
nerves.
Experts don't know what causes this problem
with the gene. In most cases of acoustic neuroma, there is no known cause. This
faulty gene is also inherited in neurofibromatosis type 2, a rare disorder that
usually involves the growth of tumors on the hearing and balance nerves on both
sides of your head (bilateral vestibular schwannomas).
Risk factors
Neurofibromatosis type
2
The only confirmed risk factor for acoustic
neuroma is having a parent with the rare genetic disorder neurofibromatosis
type 2. However, neurofibromatosis type 2 only accounts for about 5% of
acoustic neuroma cases.
A hallmark characteristic of neurofibromatosis
type 2 is the development of noncancerous tumors on the hearing and balance
nerves on both sides of the head, as well as on other nerves.
Neurofibromatosis type 2 (NF2) is known as an
autosomal dominant disorder, meaning that the mutation can be passed on by just
one parent (dominant gene). Each child of an affected parent has a 50-50 chance
of inheriting it.
Complications
An acoustic neuroma may cause a variety of
permanent complications, including:
·
Hearing loss
·
Facial numbness and
weakness
·
Difficulties with
balance
·
Ringing in the ear
Large tumors may press on your brainstem,
preventing the normal flow of fluid between your brain and spinal cord
(cerebrospinal fluid). In this case, fluid can build up in your head
(hydrocephalus), increasing the pressure inside your skull.
Diagnosis
Acoustic neuroma is often difficult to
diagnose in the early stages because signs and symptoms may be easy to miss and
develop slowly over time. Common symptoms such as hearing loss are also
associated with many other middle and inner ear problems.
After asking questions about your symptoms,
your doctor will conduct an ear exam. Your doctor may order the following
tests:
·
Hearing
test (audiometry). In this test,
conducted by a hearing specialist (audiologist), you hear sounds directed to
one ear at a time. The audiologist presents a range of sounds of various tones
and asks you to indicate each time you hear the sound. Each tone is repeated at
faint levels to find out when you can barely hear.
The audiologist may also present various words to determine your
hearing ability.
·
Imaging. Magnetic resonance imaging (MRI) with
contrast dye is usually used to diagnose acoustic neuroma. This imaging test
can detect tumors as small as 1 to 2 millimeters in diameter.
If MRI is unavailable or you can't have an MRI scan for
some reason, computerized tomography (CT) may be used.
However, CT scans may miss very small tumors.
Treatment
Your acoustic neuroma treatment may vary,
depending on:
·
The size and growth of
the acoustic neuroma
·
Your overall health
·
Severity of symptoms
To treat acoustic neuroma, your doctor may
suggest one or more of three potential options: monitoring, surgery or
radiation therapy.
Monitoring
If you have a small acoustic neuroma that
isn't growing or is growing slowly and causes few or no signs or symptoms, you and
your doctor may decide to monitor it. Monitoring may be recommended if you're
an older adult or otherwise not a good candidate for more-aggressive treatment.
Your doctor may recommend that you have
regular imaging and hearing tests, usually every 6 to 12 months, to determine
whether the tumor is growing and how quickly. If the scans show the tumor is
growing or if the tumor causes progressive symptoms or other difficulties, you
may need to undergo treatment.
Surgery
You may need surgery to remove an acoustic
neuroma, especially if the tumor is:
·
Continuing to grow
·
Very large
·
Causing symptoms
Your surgeon may use one of several techniques
for removing an acoustic neuroma, depending on the size of your tumor, hearing
status and other factors.
The goal of surgery is to remove the tumor and
preserve the facial nerve to prevent facial paralysis. Removing the entire
tumor may not be possible in certain cases — for example, if the tumor is too
close to important parts of the brain or the facial nerve.
Surgery for an acoustic neuroma is performed
under general anesthesia and involves removing the tumor through the inner ear
or through a window in your skull.
Sometimes, surgical removal of the tumor may
worsen symptoms if the hearing, balance, or facial nerves are irritated or
damaged during the operation. Hearing may be lost on the side where the surgery
is performed, and balance is usually affected temporarily.
Complications may include:
·
Leaking cerebrospinal
fluid through the wound or nose
·
Hearing loss
·
Facial weakness or
numbness
·
Ringing in the ear
·
Balance problems
·
Persistent headache
·
Rarely, infection of
the cerebrospinal fluid (meningitis)
·
Very rarely, stroke or
brain bleeding
Radiation therapy
There are several types of radiation therapy
used to treat acoustic neuroma:
·
Stereotactic
radiosurgery. Your doctor may
recommend a type of radiation therapy known as stereotactic radiosurgery. It's
often used if your tumor is small (less than 2.5 centimeters in diameter), you
are an older adult or you cannot tolerate surgery for health reasons.
Stereotactic radiosurgery, such as Gamma Knife radiosurgery,
uses many tiny gamma rays to deliver a precisely targeted dose of radiation to
a tumor without damaging the surrounding tissue or making an incision.
The goal of stereotactic radiosurgery is to stop the growth of a
tumor, preserve the facial nerve's function and possibly preserve hearing.
It may take weeks, months or years before you notice the effects
of radiosurgery. Your doctor will monitor your progress with follow-up imaging
studies and hearing tests.
Risks of radiosurgery include:
o Hearing loss
o Ringing in the ear
o Facial weakness or numbness
o Balance problems
o Continued tumor growth
·
Stereotactic
radiotherapy. Fractionated
stereotactic radiotherapy (SRT) delivers a small dose of radiation to the tumor
over several sessions. SRT is done to curb the growth of the tumor
without damaging surrounding brain tissue.
·
Proton
beam therapy. This type of
radiation therapy uses high-energy beams of positively charged particles called
protons. Protons are delivered to the affected area in targeted doses to treat
tumors and minimize radiation exposure to the surrounding area.
Supportive therapy
In addition to treatment to remove or stop the
growth of the tumor, your doctor may recommend supportive therapies to address
symptoms or complications of an acoustic neuroma and its treatment, such as
dizziness or balance problems.
Cochlear implants or other treatments may also
be recommended to treat hearing loss.
Coping and support
Dealing with the possibility of hearing loss
and facial paralysis and deciding which treatment would be best for you can be
quite stressful. Here are some suggestions you may find helpful:
·
Educate
yourself about acoustic neuroma. The more you know, the better prepared you'll be to make
good choices about treatment. Besides talking to your doctor and your
audiologist, you may want to talk to a counselor or social worker. Or you may
find it helpful to talk to other people who've had an acoustic neuroma and
learn more about their experiences during and after treatment.
·
Maintain
a strong support system. Family
and friends can help you as you go through this difficult time. Sometimes,
though, you may find the concern and understanding of other people with
acoustic neuroma especially comforting.
Your doctor or a social worker may be able to put you in touch
with a support group. Or you may find an in-person or online support group
through the Acoustic Neuroma Association.
Preparing for your
appointment
You're likely to start by seeing your family
doctor or a general practitioner. Your doctor may then refer you to a doctor
trained in ear, nose and throat conditions or a doctor trained in brain and
nervous system surgery (neurosurgeon).
Because there's often a lot to talk about during
your appointment, it's a good idea to be well prepared. Here's some information
to help you get ready for your appointment, and what to expect from your
doctor.
What you can do
·
Write
down any symptoms you're experiencing, including any that may seem unrelated to the reason for
which you scheduled the appointment.
·
Make
a list of all medications, vitamins
or supplements that you're taking.
·
Ask
a family member or friend to join you, if possible. Sometimes it can be difficult to remember all
the information provided to you during an appointment. Someone who accompanies
you may remember something that you missed or forgot.
·
Write
down questions to ask your doctor.
Preparing a list of questions will help you
make the most of your time with your doctor. For acoustic neuroma, some basic
questions to ask your doctor include:
·
What is likely causing
my symptoms?
·
Are there any other
possible causes for my symptoms?
·
What kinds of tests do
I need?
·
What treatment options
are available?
·
Which one do you
recommend for me?
·
What is the likelihood
of side effects from each treatment option?
·
What happens if I do
nothing?
·
Are there any
brochures or other printed material that I can take home with me? What websites
do you recommend visiting?
In addition to the questions that you've
prepared to ask your doctor, don't hesitate to ask questions during your
appointment.
What you can expect
from your doctor
Your doctor is likely to ask you a number of
questions. Being ready to answer them may reserve time to go over any points
you want to spend more time on. Your doctor may ask:
·
When did you first
begin experiencing symptoms?
·
Have your symptoms
been continuous or occasional?
·
How severe are your
symptoms?
·
Do you have any family
members with an acoustic neuroma?
·
At its current level, do
you feel the hearing in the affected ear is useful to you in any way? For
example, can you use that ear on the telephone, or does that ear help you tell
where sound is coming from?
·
Do you have regular
headaches currently or have you had them in the past?
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