Acoustic neuroma is a noncancerous tumor developing on the vestibular nerve, which courses from the inner ear to the brain. The tumor is slow-growing in most of the cases. The branches of the vestibular nerve are responsible for balance, and hearing. Acoustic neuroma may exert pressure on the nerve leading to hearing loss, ringing in the ear and instability.
The origin of Acoustic neuroma is Schwann cells that cover the vestibular nerve. In rare cases, there is rapid growth, putting pressure against the brain and disturb vital functions of the body.
What are the signs and symptoms of acoustic neuroma?
The signs may often go unnoticeable. The most common initial symptoms of an acoustic neuroma include,
A decrease in hearing power, more prominent on one side.
Tinnitus, which is a ringing sensation in the ear.
Dizziness or vertigo
Facial numbness, weakness or loss of muscle movement. (Due to pressure on the adjacent nerves)
Difficulty to swallow
Hoarseness of voice
What are the causes of Acoustic Neuroma?
Based on the causes of acoustic neuroma, it is of two types:
Sporadic form of acoustic neuroma
Acoustic neuroma associated with neurofibromatosis type II
Some other causes of acoustic neuroma are
Radiation therapy to head and neck
Increased use of cell phones
Neurofibromatosis type II or NF2 is a congenital disorder, involving the growth of non-cancerous tumors of the nervous system. This is the most common cause of acoustic neuroma and can be bilateral by the age of 30 years. The patients with NF2 also have other tumors affecting the spinal cord and brain, which can cause hindrance with the nervous system and other vital functions of the body.
How is it diagnosed?
In most of the cases, it is difficult to diagnose acoustic neuroma as the signs go unnoticed. Following are some of the test that can help in diagnosing the tumor.
Audiometry - The test is performed by an audiologist, in which the patient hears the sound directed to one year at one time. A wide range of sounds in different tones is radiated and the patient is asked to point out each time he/she is able to hear it.
Radio-imaging - To confirm the diagnosis and measure the size of the tumor, MRI is done. The doctor can also do a CT scan instead of an MRI.
Can acoustic neuroma lead to vision problems?
There is no direct relation of an acoustic neuroma and vision. The tumor has a direct effect on the ear and hearing effect and may also cause weakness in the facial muscles. However, there is no direct relation of the tumor with the eyesight.
How is it treated?
There are 3 basic approaches for the treatment of acoustic neuroma:
Wait and watch
Depending upon the extent and overall condition of the tumor, the doctor may opt for any of the above treatment options.
Wait and watch
In cases of very small sized tumors which do not show any growth are usually preferred to be observed. However, the doctor may recommend you to get an MRI or a CT scan every 6-12 months. The patient will need to start treatment if there are any signs of aggression or other changes in the tumor.
The goal of the surgery is to remove the tumor while preserving the surrounding structures such as facial nerve and prevent facial paralysis and save hearing sensation. The surgery is performed under general anesthesia. Sometimes it is difficult to remove the entire tumor due to its close proximity to the vital structures such as brain or cranial nerves. There are some of the best ENT hospitals in India, which are well-equipped to perform such surgeries. Following complications may be associated with surgical treatment such as,
Leakage of cerebrospinal fluid through the incision
Bleeding in the brain
People with older age or chronic ailments such as heart disorders are advised to get stereotactic radiation such as gamma knife surgery, in which several gamma rays are concentrated on the tumor to cause destroy it without causing any damage to the surrounding structure. The procedure is conducted with high precision and with the help of an MRI or CT scan.
The radiotherapy is given in fractions over multiple sessions and it may take several months or years to show evidence of improvement.