Acoustic Neuroma

Overview

An acoustic neuroma, also known as vestibular schwannoma, is a noncancerous tumor that develops on the main nerve leading from the inner ear to the brain. This nerve, called the vestibular nerve, is responsible for balance and hearing. Pressure from the acoustic neuroma can lead to symptoms such as hearing loss, ringing in the ear (tinnitus), loss of balance, dizziness, and facial numbness. The tumor is formed from the Schwann cells covering the vestibular nerve and is typically slow-growing, though it may grow quickly in some cases. Treatments for acoustic neuroma include monitoring, radiation, and surgical removal. The cause of acoustic neuromas can sometimes be linked to a problem with a gene on chromosome 22, and it is associated with a condition called neurofibromatosis type 2. Early diagnosis and treatment can help prevent complications such as total hearing loss and brainstem compression.

Understanding the disease

Symptoms

The symptoms of an acoustic neuroma may include:

• Hearing loss, usually gradual over months to years and usually occurring on one side or being worse on one side
• Ringing in the affected ear, known as tinnitus
• Loss of balance or feeling unsteady
• Dizziness
• Facial numbness, and very rarely, weakness or loss of muscle movement It is important to consult a healthcare professional if you notice any of these symptoms. Early diagnosis may help keep the tumor from causing complications.

Risk Factors

The main risk factor for developing 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. In most cases, the cause of acoustic neuroma is unknown, and it is believed to occur due to a problem with a gene on chromosome 22 that produces a tumor suppressor protein. This gene change can lead to the growth of tumors on the hearing and balance nerves on both sides of the head, known as bilateral vestibular schwannomas.

Development

Acoustic neuromas develop from the Schwann cells covering the vestibular nerve, which is the main nerve leading from the inner ear to the brain. The vestibular nerve is responsible for balance and hearing. An acoustic neuroma, also known as vestibular schwannoma, occurs when these Schwann cells grow abnormally and form a noncancerous tumor. The exact cause of the gene problem that leads to the development of acoustic neuromas is not known, but it is believed to be inherited in people with the rare disorder called neurofibromatosis type 2. In these cases, tumors may grow on both sides of the head, affecting both balance and hearing nerves.

Assessment and Diagnosis

Triage

You should see a healthcare professional if you notice hearing loss in one ear, ringing in your ear, or balance problems. Early diagnosis of an acoustic neuroma may help keep the tumor from growing large enough to cause complications such as total hearing loss.

Diagnosis

To diagnose an acoustic neuroma, your healthcare team will likely perform the following tests:

1. Audiometry: A hearing test conducted by an audiologist, where sounds of various tones are presented to one ear at a time, and you indicate when you can hear them. The audiologist may also present words to test your hearing.
2. Imaging: Magnetic resonance imaging (MRI) with contrast dye is usually used to diagnose an acoustic neuroma, as it can detect tumors as small as 1 to 2 millimeters in diameter. If MRI is not available, computerized tomography (CT) scans may be used, but they may miss small tumors. Based on your symptoms, size and growth rate of the acoustic neuroma, and your overall health, your healthcare team will recommend one of the following treatment options: monitoring, surgery, or radiation therapy. The likelihood of side effects from each treatment option varies and depends on the individual case. If left untreated, an acoustic neuroma may continue to grow and cause further symptoms. It's important to discuss your options with your healthcare provider and ask for any brochures or printed material to help you make an informed decision.

Management and Treatment

Complications

Potential complications of acoustic neuroma may include:

1. Hearing loss: As the tumor grows, it can cause progressive hearing loss, often starting gradually over months to years and affecting one ear more than the other.
2. Balance problems: Pressure from the tumor on the vestibular nerve can cause issues with balance and make a person feel unsteady.
3. Dizziness: The tumor can cause a spinning sensation or dizziness.
4. Facial numbness and weakness: In rare cases, an acoustic neuroma can compress the facial nerve, leading to numbness and, in some instances, weakness or loss of muscle movement in the face.
5. Brainstem compression: Large tumors may press on the brainstem, which can result in life-threatening complications.
6. Hydrocephalus: If the tumor obstructs the flow of cerebrospinal fluid between the brain and spinal cord, fluid can build up in the head, leading to increased pressure inside the skull (hydrocephalus). It is essential to see a healthcare professional if you experience hearing loss in one ear, ringing in your ear, or balance problems, as early diagnosis and treatment can help minimize potential complications.

Treatment

Treatments for acoustic neuroma include monitoring, radiation, and surgical removal. The choice of treatment depends on various factors such as the size and location of the tumor, the patient's overall health, and the specific symptoms experienced. Monitoring may be recommended for small, slow-growing tumors that are not causing significant issues. Radiation therapy can be used to shrink the tumor or slow down its growth, while surgical removal is typically reserved for larger tumors or those causing significant symptoms. Clinical trials may also be an option for patients seeking alternative treatments. It's important to consult a healthcare professional to determine the most suitable treatment plan for each individual case.

Preparing for medical consultation

To prepare for an appointment for acoustic neuroma, you should:

1. Write down any symptoms you are experiencing, including any that may seem unrelated to the reason for the appointment.
2. Make a list of all medicines, vitamins, or supplements that you are taking.
3. Ask a family member or friend to join you, if possible, to help remember important information.
4. Prepare a list of questions to ask your healthcare provider, such as the cause of your symptoms, possible treatments, and prognosis.
5. Be aware of any pre-appointment restrictions and ask if there is anything you need to do in advance.
6. Write down a list of your symptoms, noting if there is anything that seems to trigger them or make them better.
7. Take a list of all your medicines, including any vitamins or supplements.
8. Request any brochures or printed material for further reading.
9. Consider joining a support group, either in person or online, for additional support and understanding. Remember to arrive on time and bring your prepared questions and lists with you to make the most of your appointment.