Neurinoma of the acoustic nerve, vestibular or acoustic schwannoma, neurinoma of the vestibulo-cochlear nerve. This is disease, the treatment of which our clinic specializes.
The neurinoma of the vestibulo-cochlear nerve is a tumor growing from the nerve responsible for hearing and balance. These tumors grow slowly. However, because of their location, they can couse extremely unfavorable complications . During growing, the tumor begins to cause hearing loss on the side of the location, noise and ringing, balance disorders and dizziness, paresis of facial nerve. In neglected cases, increases intracranial pressure and decreased vision (hydrocephalus is progressing).
Other nerves are also affected. Symptoms of distraction of other nerves are double vision, numbness or pain in the face, difficulty of swallowing and loss of voice. The compression of the conductive pathways can cause weakness and paralysis of the limbs, a violation of sensitivity.
The ear is the organ of hearing and, in mammals, balance. In mammals, the ear is usually described as having three parts—the outer ear, middle ear and the inner ear. The outer ear consists of the pinna and the ear canal. Vestibulocochlear (pre-vertebral or eighth cranial) nerve is responsible for the transmission of equilibrium and hearing signals from the inner ear to the brain.
The outer ear directs sound signals through the ear canal to the eardrum, which vibrates the auditory ossicles (malleus, anvil and stapes) in the middle ear. The stapes transmit oscillations to the oval window of the cochlea the inner ear. The snail has a spiral shape and is filled with a liquid that moves in response to vibrations. The flow of the fluid stimulates thousands of hair cells and they transmit signals through the cochlear (cochlear) nerve, which are perceived by the brain as auditory. Closely adjacent to the cochlea are three mutually perpendicular semicircular canals. They are able to catch the position of the head and body position. Signals from the semicircular canals are transmitted to the brain through the upper and lower vestibular nerves (responsible for the equilibrium). The cochlear and vestibular nerves form a single trunk in the middle of the bone internal auditory canal before exiting from it in the direction of the brainstem. In the middle of the canal, the vestibulocochlear nerve is located very closer the facial nerve. The facial (the seventh craniocerebral) nerve is responsible for the movements of the facial muscles. The close interrelation of the vestibulocochlear and facial nerves explains why the weakness of the facial muscles can arise with the growth of the neurinoma of the auditory (vestibulo-cochlear) nerve
The neurinoma of the vestibulo-cochlear nerve. What is it?
Neurinoma of the auditory nerve or vestibular schwannoma is a slowly growing tumor that develops from the Schwann cells of the coat of the vestibulocochlear nerve. As it grows, it spreads from the place of origin in the internal auditory canal into the space between the brain stem and the bone, which is called the bridge-cerebellar angle. A pear-shaped tumor can continue to grow and contract the trigeminal nerve, which is responsible for the sensitivity of the face. In the end, the tumor can squeeze the brain stem. Neurinomas of the auditory nerve are classified by size into small (less than 1.5 cm), medium (1.5 to 2.5 cm) and large (more than 2.5 cm).
What are the symptoms?
Symptoms caused by the size and growth of the tumor. The most typical symptom is one-sided hearing loss on the side of the tumor, which is often overlooked or mistakenly associated with other causes (for example, age-related changes in hearing). Small tumors usually do not extend beyond the bone channel and lead to unilateral reduction of hearing, tinnitus (ringing and noise in the ear), coordination disorders and dizziness. As the tumor grows, hearing loss can progress, weakness of the face and impaired coordination, balance are added. Large tumors cause pression on the brain stem, which aggravates the disorder of coordination, causes a sensitivity disorders. Involving the trigeminal nerve leads to numbness of the face and sometimes to the pains of the arrow as a type of neuralgia. With increasing compression of the trunk, the pathways of circulation of the cerebrospinal fluid overlap, leading to hydrocephalus. It lead to headache, loss of vision, nausea, vomiting and other symptoms.
What are the causes?
In general, the causes of the tumor of the auditory nerve are still unknown. None of the environmental factors (such as the use of mobile phones or eating habits) has a proven impact on the development of these tumors. Neurinomas of the vestibulocochlear nerve can be both sporadic (occur without apparent causes), and develop with such a hereditary disease as type 2 neurofibromatosis (NF-2). Sporadic cases account for 95%, while 5% of the remaining neurinas are associated with NF-2.
Neurofibromatosis is a rare disease that can occur in two forms. Type 1 – causes neural tumors throughout the body, especially in the skin. Type 2 – more often affects the central nervous system, in particular causes the development of bilateral neurinomas auditory nerves, creating a risk of complete hearing loss. The bilateral nature of the process influences on treatment, because the priority is the preservation of hearing.
Neurinoma of the vestibulocochlear nerve affects about 10 people per 1 million. Women are more common than men and are usually diagnosed between the ages of 30 and 60 years.
How to diagnose?
The doctor in detail asks about your complaints and history (history of previous and family illnesses), then make a general and neurological examination.
The final diagnosis is possible only after an additional examination, which usually takes no more than 1-2 days. Diagnostic procedures may include:
Magnetic resonance imaging (MRI) of the brain with contrast enhancement is the gold standard for diagnosing tumors of the brain, including the neurinoma of the auditory nerves. MRI is a non-invasive, painless and safe study that uses a magnetic field and radio waves to obtain a detailed image of the brain tissue. MRI is very useful for detecting brain lesions and their effect on surrounding brain structures.
Computer tomography (CT) is a non-invasive technique in which an image of internal structures is acquired using X-rays and a computer. It is especially useful for studying the state of bone structures and their changes under the influence of the tumor (for example, widening of the internal auditory canal or destruction of the adjacent bone).
Audiogram is an examination of the hearing function performed by an otoneurologist (specialist in diseases of the auditory nerves). During the study, the headphones are worn on the patient, through which a number of sounds are heard in a certain sequence for each ear separately. Also, the study can be supplemented with a test for the recognition of oral speech. This test allows you to detect hearing loss, its side (with changes not noticeable to the patient) and the level at which the auditory analyzer (middle or inner ear) is struck.
Also, the doctor may prescribe a number of more detailed studies that are necessary in your particular case.
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