An acoustic neuroma is a benign growth of tissue in the inner auditory canal. This tissue growth is rare. It is located in the petrous bone in the inner auditory canal and originates from the vestibular nerve. The acoustic neuroma grows very slowly and usually only occurs on one side.
You can find all the important information and selected acoustic neuroma specialists here.
Acoustic neuromas are located at the exit of the vestibular nerve into the brain in the inner auditory canal. The cerebellopontine angle is affected later, and only when the tumor has grown larger. The cerebellopontine angle is the niche between the cerebellum and the brain stem.
People between the ages of 30 and 50 have an increased risk of developing acoustic neuroma, but the brain tumor is most common in patients aged 50 to 60.
The benign brain tumor develops from Schwann cells. This cell type insulates the cranial nerves in the brain from the outside. As a result, the cells accelerate the transmission of information between the nerve cells.
In patients with an acoustic neuroma, Schwann cells grow rapidly and uncontrollably. They encase themselves in a capsule of connective tissue. In this way, they separate themselves from the surrounding tissue.
The neurinoma originates from thevestibular nerve(Nervus vestibularis). It is therefore correctly referred to as a vestibular schwannoma. This vestibular nerve transmits information from the vestibular organ in the inner ear to the brain. The exact cause of the tissue overgrowth is still unclear.
The auditory nerve runs in the immediate vicinity of the vestibular nerve. This is very often damaged with a sudden loss of hearing. Hearing loss is usually the first symptom of an acoustic neuroma.
The loss of the sense of balance progresses very slowly and therefore usually goes unnoticed. For this reason, the tumor used to be referred to as an acoustic neuroma from the auditory nerve(nervus acusticus).
The vestibular nerve originates from the vestibular organ and leads to the brain. This is where an acoustic neuroma forms © Henrie | AdobeStock
In rare cases, the excess tissue formation is a symptom of hereditary neurofibromatosis type 2, in which case it can even occur on both sides. Neurofibromatosis is a disease in the course of which benign tumors
develop.
Acoustic neuroma usually manifests itself in the form of sudden hearing loss. As the growth is slow, further symptoms usually only become apparent after a few months. Some of the symptoms only occur on the side of the body where the tumor is located.
The benign tumor can be recognized by the following symptoms:
Initially, hearing and sense of balance are impaired. Patients notice that their hearing is worse in one ear. The hearing test reveals hearing loss in the form of sensorineural hearing loss (sensorineural hearing loss). High frequencies above 1,000 Hz are particularly affected. High-pitched sounds are no longer audible at all or are heard differently.
Acoustic neuroma can also trigger a sudden loss of hearing: The patient suddenly hears nothing or hardly anything at all in one ear. Sometimes tinnitus also occurs. This ringing in the ears consists of high-pitched sounds (ringing, hissing) and is very distressing. The external auditory canal feels numb as its sensitivity is reduced.
If the vestibular nerve is also affected, the patient feels nauseous. Attacks of dizziness occur. They suddenly start to sway (vertigo). More rarely, there is a feeling that everything is spinning around him (rotary vertigo). His gait becomes unsteady.
His eyes move back and forth quickly and slowly(nystagmus), as is usual with vertigo. This is usually the case when the neurinoma patient makes a rapid head movement or when it is dark and there is therefore no rapid fixation of the eyes.
Larger acoustic neuromas also affect the facial nerve, as this also runs through the inner auditory canal. The patient's facial expressions are restricted on one side. If the neurinoma presses on the trigeminal nerve, the sensitivity of the facial skin is also reduced (numbness).
In the worst case, the tumor prevents the cerebrospinal fluid (CSF) from draining sufficiently via the brain stem. The accumulated water and the resulting increased brain pressure then often cause nausea and vomiting.
The patient complains of headaches and has the feeling that he can no longer move his neck properly (neck stiffness). His vision is also altered: They see double vision, for example.
Anyone experiencing these symptoms should consult a specialist(ENT specialist or neurologist) as soon as possible.
The ear, nose and throat specialist will look at the patient's external auditory canal and eardrum. If the patient only has non-specific symptoms such as dizziness and headaches, further examinations will follow. These serve to differentiate the disease from diseases with similar symptoms.
Acoustic neuroma is diagnosed with the help of
In the case of a suspected diagnosis, the patient hears certain words and sounds through headphones at the ENT doctor's, which they have to repeat.
Brainstem audiometry (BERA) is used to check the functionality of the auditory nerves. The patient hears clicking noises. An electrode attached behind the ear records the extent to which the auditory system transmits acoustic stimuli to the brain unhindered.
A balance test with hot and cold water is also part of the diagnosis. The doctor rinses warm water into the external auditory canal and measures the eye movements (nystagmus). If the reactions are not equal on both sides, there is an underfunction of one of the vestibular organs.
A magnetic resonance tomography (MRT) providesdefinitive certainty if it can detect an accumulation of contrast medium in the inner auditory canal in the area of the vestibular nerve.
Smaller tumors that are no larger than 3 centimetres are surgically removed via the middle cranial fossa (ENT specialist). Larger tumors, on the other hand, are approached from behind (suboccipitally by the neurosurgeon).
Due to the location of the tumor, surgeons must proceed with great care. It is important to avoid damage to
intact tissue. It is essential to preserve the facial nerve and, in a high percentage of cases, the auditory nerve. If the neurinoma is completely removed, it usually does not recur.
Smaller growths are treated with radiotherapy. Other doctors regularly monitor the growth of tumors using magnetic resonance imaging.
In some cases, it is sufficient to wait and monitor the tumor regularly (wait and see). This is the method of choice if
In the case of inoperable tumors, radiotherapy is used to destroy the neurinoma or inhibit its growth. This method involves irradiating the tumor with a high dose of radiation.
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