A Simple Guide to Acoustic neuroma

A Simple Guide to Acoustic neuroma
---------------------------------------------------

What are Acoustic neuroma ?
------------------------------------------------

Acoustic neuroma is a neurofibroma of the eight nerve.


Who are at risk of Acoustic neuroma?
-------------------------------------

1.Both sexes are equally affected.

2.Acoustic neuroma occurs more in the 50- 60 age group.

3.It forms 5-10% of the intracranial tumors in adults.


What are the different types of Acoustic neuroma?
--------------------------------------------------------

1.Neurofibroma I -
a. Unilateral acoustic neuroma usually
Bilateral acoustic neuromas are not common.

b. occurs in adult life,

c. the tumor involve the 8th nerve,

d. can involve any other cranial nerve or the spinal root.

e.Incidence is usually 90-95%

2.Neurofibroma II -
a. bilateral acoustic neuromas are common

b. occurs before the age of 21.

c. affects the entire nerve

d. autosomal dominant inheritance.

e. Incidence is about 5 to 10%.


What are the Causes of Acoustic neuroma?
------------------------------------------------------

Acoustic neuroma in the adult begins in the Schwann's cells of the vestibular portion of the 8th nerve inside the internal auditory canal.

The tumor grows slowly and can extend into the posterior fossa to occupy the space between the cerebellum and the pons.

Because of its location, it can also compress the 5th, 7th, and less often, the 9th and 10th cranial nerves.

If it grows larger, it may also compress the pons and lateral medulla of the brain, causing blockage of the cerebrospinal fluid and increased intracranial pressure.


What are the symptoms and signs of Acoustic neuroma?
-------------------------------------------------------

Symptoms:
--------------
1.unilateral hearing loss

2.tinnitus with unilateral high-pitched ringing sound

3.loss of sense of balance

4.vertigo

5.nausea and vomiting

6.altered gait

7.pressure in the ear

8.rarely headache and altered consciousness.

Signs:
-------------

1.unilateral facial weakness.

2.sensory impairment of the nerve

3.impairment of glandular secretions

4.loss of taste

5.loss of sensation in one side of the face and mouth

6.rarely altered gag or swallowing reflexes.


How are diagnosis of Acoustic neuroma made?
------------------------------------------------------------

1.Contrast-enhanced CT will detect almost all acoustic neuromas that are greater than 2.0 cm in diameter

2.MRI with gadolinium enhancement may show even smaller tumors

3.Audiology and vestibular tests are done to check for Nerve versus conduction hearing loss.


What is the Treatment of Acoustic neuroma?
-------------------------------------------

Treatment of acoustic neuroma is usually by surgery and radiotherapy.

Conservative treatment
--------------------------

In some cases because the neuroma grow so slowly, the tumor is monitored by annual MRI to see its growth.

This method is common among patients over 70 years old.

In rare cases, acoustical neuroma have been known to disappear spontaneously.

Acoustic neuroma may result in gradual hearing loss and tinnitus.


Surgery
-----------------

Surgical removal of acoustic neuroma usually involve microsurgery to remove the tumor.

The superior and inferior vestibular nerves are removed at surgery.

This effectively restores balance in the patient.

Radiation treatment
-----------------------

Radiotherapy using gamma knife radiosurgery or fractionated stereotactic radiotherapy does not remove the tumor but is able to slow or stop its growth.


What is the Prognosis of Acoustic neuroma?
-------------------------------------------

Prognosis is good in all early diagnosis and small tumors.

Large tumors may give rise to residual neurolgical damage even afer removal.