A person may experience one-sided hearing loss, ringing in the ears, and loss of balance. These symptoms can indicate numerous health conditions. One of them is an acoustic neuroma.
Acoustic neuroma is a non-cancerous tumour affecting the nerve tissues that run from the inner ear to the brain. The nerve is responsible for hearing and balance. But when the tumour presses on the nerve, it causes hearing loss and ringing in the ears, known as tinnitus. As the tumour progresses, it increases the pressure on the brain, which could be fatal. However, it is essential to note that the tumour does not spread to other body parts.
The blog delves deep into the acoustic neuroma, its symptoms, causes, and various treatments.
What is acoustic neuroma?
Acoustic neuroma or vestibular schwannoma is a benign and slow-growing tumour that grows in the vestibular nerve that runs between the inner ear and the brain. The various branches of the vestibular nerve are responsible for balance and hearing. However, when the tumour increases the pressure on the nerve, it results in hearing loss, ringing in the ears, and loss of balance.
Typically, acoustic neuroma affects the Schwann cells that cover and support the nerves. In rare cases, the tumour rapidly grows and enlarges, causing increased pressure on the brain and may interfere with the body’s vital functions. It could be fatal. But, as mentioned earlier, the tumour does not spread to other body parts. Patients with acoustic neuroma require regular monitoring, radiation, and, sometimes, surgery to prevent the symptoms from worsening.
The National Orgnization of Rare Diseases (NORD) study shows that acoustic neuroma affects one in every 1,000 people, and nearly 2500 new cases are registered in the United States annually. People between the age of 30 to 60 are susceptible to developing acoustic neuroma.
Acoustic neuroma has several other names, such as acoustic neurinoma, vestibular schwannoma, and auditory nerve tumour.
What are the types of acoustic neuroma?
There are two different types of acoustic neuroma. They are as follows:
- Sporadic, unilateral acoustic neuroma: In nearly 95% of the patients, the tumour grows on one side of the body. These tumours are sudden and non-hereditary mutations. Sporadic, unilateral acoustic neuroma can occur at any age but is commonly seen in patients between the age of 30 to 60.
- Genetic, bilateral acoustic neuroma: As the name suggests, the tumour occurs on both sides of the body. People with neurofibromatosis type 2, a genetic disorder, are susceptible to this acoustic neuroma. In neurofibromatosis, the mutation of chromosome 22 affects Schwann cell production resulting in schwannoma-like tumours in the entire body. Treatment for this is different from that of unilateral tumours.
What are the symptoms of acoustic neuroma?
Hearing loss, dizziness, ringing in the ears, are common ear symptoms in many other ear disorders . Therefore, diagnosing acoustic neuroma can be challenging, and doctors can easily miss it as it may take years to develop. As the tumour affects the nerves responsible for balance and hearing, the following are some of the symptoms of acoustic neuroma:
- One-sided hearing loss: More than 90% of acoustic neuroma patients develop a certain degree of one-sided hearing loss. Such patients have difficulty listening and locating noises in a crowded place and find it challenging to follow or hold a conversation for a long time. The hearing loss typically worsens over the years and may result in complete deafness in one ear. The sudden loss of hearing is one of the first signs that can lead to diagnosis or may occur before the tumour is discovered – for months or years. When there is a compression on the nerve that is responsible for hearing, it affects the way a patient hears sounds and the clarity of hearing. Mild hearing loss may not be noticeable and can lead to delayed diagnosis.
- A feeling of fullness in ears: Patients with acoustic neuroma often experience a sense of fullness in their ears, similar to if their ears are filled with water. It is due to hearing loss due to the tumour.
- Ringing in the ear: The ringing in the ear is known as tinnitus. It is a common symptom of several ear-related disorders and acoustic neuroma. Some patients experience a high-pitched tone in the affected ear, whereas others experience sounds similar to hissing, buzzing, or roaring. Patients may experience tinnitus and hearing loss or may only experience only tinnitus. The ringing in the ear recurs or is constant, with single or multiple tones. Sometimes, the noise can be quiet or high.
- Loss of balance and vertigo: These are early signs of acoustic neuroma. As the tumour grows, it compresses the cerebellum resulting in falls and worsening symptoms. When patients lose their balance and fall, they fall on the side of the tumour. The sense of spinning or tilting, known as vertigo, is not typically linked to acoustic neuroma but can occur due to the growing tumour or bleeding.
Since the tumour puts immense pressure on other cranial nerves that are closer to the tumour, it causes other following symptoms:
- Face numbness: When the tumour presses on the trigeminal nerve, it may result in ongoing or periodic facial numbness and tingling on the affected side. Other symptoms may include tingling near the corner of the mouth or cheek, eye irritation, eye redness, and numbness in the eyes that affects the blinking reflexes.
- Facial twitching and weakness: Tumour that presses on the facial nerves may cause facial twitching and weakness. Facial numbness also occurs during the later stages of acoustic neuroma and is the lesser-known symptom during diagnosis.
- Difficulty swallowing: A patient may find swallowing difficult when the tumour presses on the vagal and hypoglossal nerves that control swallowing, including the sensation in the throat and movement of vocal cords and tongue.
- Taste and tear production changes: It is a lesser-known symptom that requires medical attention. The pressure on the nerve that controls taste and tear production results in dry eyes or unexpected tears and changes in taste.
- Immense headaches and pressure: As the tumour grows, it puts pressure on the lining of the inside of the skull, called the dura. There are several sensory fibres present in the dura. Headaches from acoustic neuroma may be dull or aching and are typically on one side of the head. The patient may experience pain radiating to the neck, top, or front of the head.
Cholesteatoma, labyrinthitis, vestibular neuritis, and Meniere’s disease also cause the above mentioned symptoms. Occasionally, an acoustic neuroma becomes large that it can compress the brainstem and become fatal.
When to seek medical help?
If a person notices the symptoms of acoustic neuromas, such as hearing loss on one side, ringing in the ear, or loss of balance, seeking medical help is required. Early diagnosis may prevent the tumour and symptoms from developing further.
