About Acoustic Neuroma (Vestibular Schwannoma)

Overview

An acoustic neuroma, also known as vestibular schwannoma, is a noncancerous tumor that develops on the nerves responsible for hearing and balance. It typically grows slowly and originates in the inner ear. This tumor can affect the nerves connecting the ear and brain, leading to symptoms such as one-sided hearing loss, tinnitus (ringing in the ears), dizziness, facial numbness, and facial weakness or paralysis. While the tumor itself does not spread to other parts of the body, it can cause complications if it presses against structures in the brain. Treatment options for acoustic neuroma include surgery or radiation therapy, which are typically determined by a doctor based on factors such as tumor size and location. It is important to consult with a healthcare professional for an accurate diagnosis and personalized treatment plan.

Causes and Risk Factors

The exact cause of acoustic neuroma is unknown, but there are several factors that may contribute to its development:

Disease causes:

• Genetic mutations: Some cases of acoustic neuroma are associated with genetic conditions like neurofibromatosis type 2 (NF2), which is caused by mutations in the NF2 gene.
• Nerve sheath cell overgrowth: The tumor arises from the cells that form the protective covering of the nerve, called Schwann cells. Abnormal growth of these cells can lead to the formation of acoustic neuroma.

Non-modifiable risk factors for acoustic neuroma cannot be changed or controlled. These include:

• Age: The risk of developing acoustic neuroma increases with age, particularly between the ages of 30 and 60.
• Gender: Women are slightly more likely to develop acoustic neuroma than men.
• Family history: Having a close relative with acoustic neuroma or NF2 increases the risk.

Modifiable risk factors for acoustic neuroma can be influenced or changed. These include:

• Radiation exposure: Previous exposure to high-dose radiation to the head and neck area may increase the risk of developing acoustic neuroma. This is more commonly seen in individuals who have undergone radiation therapy for other conditions.

It's important to note that while some risk factors are modifiable, such as radiation exposure, it is not always possible to prevent or avoid them. If you have concerns about your risk for acoustic neuroma, it's best to consult with a healthcare professional who can provide personalized advice and guidance.

Symptoms

The most common early symptoms of acoustic neuroma include:

• Hearing loss in one ear
• Tinnitus (ringing in the ears)
• Feeling of fullness in the ear
• Dizziness or vertigo
• Trouble with balance

As acoustic neuroma progresses or reaches a higher severity, other common symptoms may occur, such as:

• Numbness or tingling in the face or tongue
• Facial weakness or paralysis
• Facial twitching
• Trouble with swallowing (dysphagia)
• Headaches
• Nausea or vomiting
• Impaired movement coordination (ataxia)
• Confusion or altered mental state

In some cases, very large acoustic neuromas can disrupt the flow of the fluid surrounding the brain (cerebrospinal fluid), leading to a serious condition called hydrocephalus. This can cause symptoms like increased pressure in the skull, headache, impaired movement coordination, and altered mental state.

Remember, these are general symptoms and may vary from person to person. If you experience any of these symptoms, it's important to consult with your healthcare professional for an accurate diagnosis and appropriate treatment options.

Diagnosis

To diagnose acoustic neuroma, healthcare professionals commonly perform the following examinations, tests, and procedures:

• Medical history evaluation: The healthcare professional will ask about your symptoms and medical history.
• Physical examination: They will examine your ears and assess your balance.
• Audiometry: This hearing test evaluates your ability to hear different sounds or tones.
• Imaging tests: Typically, an MRI (magnetic resonance imaging) scan is ordered to create detailed images of the tumor and determine its location.

To determine the stage or severity of acoustic neuroma, additional examinations, tests, and procedures may be performed:

• Balance test: This test assesses your balance function and can help identify any abnormalities associated with inner ear conditions.
• Brainstem auditory evoked response (BAER): This test checks both hearing and neurological functions by measuring the brain's responses to clicking noises.
• Electroystagmography (ENG): By detecting abnormal rhythmic eye movements, this test evaluates vestibular (balance) function.
• Facial nerve function assessment: The House-Brackmann grading scale is used to evaluate facial nerve function.

It's important to note that these are general procedures, and the specific tests performed may vary based on individual circumstances. Always consult with a healthcare professional for accurate diagnosis and staging of acoustic neuroma.

Treatment Options

The goals of treatment for acoustic neuroma are to achieve long-term tumor control, preserve hearing, and minimize side effects. The recommended treatment options include:

• Observation: If the tumor is small or slow-growing, watchful waiting may be recommended. Regular monitoring with imaging tests is done to track tumor growth.
• Surgery: Surgical removal of all or part of the tumor may be necessary in certain cases. There are different surgical approaches, such as the retrosigmoid approach, which aims to preserve hearing by removing the tumor through an opening behind the ear.
• Radiation therapy: This treatment option includes stereotactic radiosurgery (SRS), which uses precise radiation beams to target the tumor. It is a noninvasive procedure that can be effective for small tumors. The gamma knife is a type of SRS.

It's important to note that medications are not typically used as primary treatments for acoustic neuroma. However, your doctor may recommend certain medications for symptom management or to address specific complications related to the condition.

Remember, treatment decisions should be made in consultation with your healthcare professional based on individual circumstances and preferences.