mineire's ppt

8/3/2019 Mineire's PPT

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The Hearing Process In the course of hearing, sound waves enter the auditory canal

and strike the eardrum, causing it to vibrate. The sound wavesare concentrated by passing from a relatively large area (theeardrum) through the ossicles to a relatively small openingleading to the inner ear. Here the stirrup vibrates, setting inmotion the fluid of the cochlea. The alternating changes of pressure agitate the basilar membrane on which the organ of

Corti rests, moving the hair cells. This movement stimulates thesensory hair cells to send impulses along the auditory nerve tothe brain.



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Ménière's disease



The inner ear contains the semi-circular canals, which also contain

fluid and hair cells. The hair cells inthe semi-circular canals sense the

position of the body and send thisinformation to the brain. This

structure allows the body to maintainbalance and equilibrium.

Anatomy and PhysiologyThe outer ear is the external portion of

the ear, which consists of the pinna,concha, and external auditory meatus.It gathers sound energy and focuses it

on the eardrum (tympanic membrane).Most human speech sounds are also

distributed in the bandwidth around 3

kHz.



Ménière's disease Is a disorder of the inner ear that

can affect hearing and balance toa varying degree. It ischaracterized by episodesof vertigo and tinnitus and

progressive hearing loss, usually inone ear. It is named after theFrench physician Prosper, who, inan article published in 1861, firstreported that vertigo was causedby inner ear disorders. Thecondition affects peopledifferently; it can range inintensity from being a mildannoyance to a chronic, lifelongdisability.



What causes the of Miniere·s

Disease?: Ménière's disease is idiopathic, but it is believedto be linked to endolymphatic hydrops, an excessof fluid in the inner ear. It is thought thatendolymphatic fluid bursts from its normalchannels in the ear and flows into other areas,causing damage. This is called "hydrops." The

membranous labyrinth, a system of membranesin the ear, contains a fluid called endolymph. Themembranes can become dilated like a balloonwhen pressure increases and drainage isblocked. This may be related to swelling of the endolymphatic sac or other tissues inthe vestibular system of the inner ear, which is

responsible for the body's sense of balance. Insome cases, the endolymphatic duct may beobstructed by scar tissue, or may be narrow frombirth. In some cases there may be too much fluidsecreted by the stria vascularis.



The symptoms may occur in the presence of a middleear infection, head trauma, or anupper respiratory tractinfection, or by using aspirin, smoking cigarettes, or

drinking alcohol. They may be further exacerbated byexcessive consumption of salt in some patients. It has alsobeen proposed that Ménière's symptoms in manypatients are caused by the deleterious effects of a herpesvirus. Herpes viridae are present in a majority of the

population in a dormant state. It is suggested that thevirus is reactivated when the immune system is depresseddue to a stressor such as trauma, infection or surgery(under general anesthesia). Symptoms then develop asthe virus degrades the structure of the inner ear.

Ménière's disease affects about 190 people per100,000. Recent gender predominance studies show thatMénière's tends to affect women more often thanmen. Age of onset typically occurs in adult years, with

prevalence increasing with age.



Signs & Symptoms: The symptoms of Ménière's are variable; not all

sufferers experience the same symptoms. However,so-called "classic Ménière's" is considered to havethe following four symptoms:

Attacks of rotational vertigo that can be severe,incapacitating, unpredictable, and last anywherefrom minutes to hours, but generally no longerthan 24 hours. For some sufferers however,prolonged attacks can occur, lasting from severaldays to several weeks, often causing the sufferer tobe severely incapacitated. This combines with anincrease in volume of tinnitus and temporary, albeitsignificant, hearing loss. Hearing may improve afteran attack, but often becomes progressivelyworse. Nausea, vomiting, and sweating sometimesaccompany vertigo, but are symptoms of vertigo,and not of Ménière's.



Fluctuating, progressive, unilateral (in one ear) or bilateral (in bothears) hearing loss, usually in lower frequencies. For some, sounds canappear tinny or distorted, and patients can experienceunusual sensitivity to noises.

Unilateral or bilateral tinnitus.

A sensation of fullness or pressure in one or both ears.

Some may have parasitic symptoms, which aren't necessarilysymptoms of Ménière's, but rather side effects from other symptoms.These are typically nausea, vomiting, and sweating which aretypically symptoms of vertigo, and not of Ménière's. Vertigo mayinduce nystagmus, or uncontrollable rhythmical and jerky eyemovements, usually in the horizontal plane, reflecting the essentialrole of non-visual balance in coordinating eye movements. Sudden,severe attacks of dizziness or vertigo, known informally as "dropattacks," can cause someone who is standing to suddenly fall. Dropattacks are likely to occur later in the disease, but can occur at anytime.



How does diagnoseMiniere·s

Disease? : There is no definitive test orsingle symptom that adoctor can use to make thediagnosis. Diagnosis is based

upon your medical historyand the presence of:

Two or more episodes of vertigo lasting at least 20minutes each

Tinnitus Temporary hearing loss

A feeling of fullness in theear



Some doctors will perform a hearing test to

establish the extent of hearing loss caused byMénières disease. To rule out other diseases,

a doctor also might request magneticresonance imaging (MRI) or computed

tomography (CT) scans of the brain.



MANAGEMENT :

Medications. The most disabling symptom of an attack of Ménières disease is dizziness.

Prescription drugs such as meclizine,

diazepam, glycopyrrolate, and lorazepam can

help relieve dizziness and shorten the attack.



Salt restriction and diuretics. Limiting dietarysalt and taking diuretics (water pills) help some

people control dizziness by reducing the amount

of fluid the body retains, which may help lower

fluid volume and pressure in the inner ear.

Other dietary and behavioral changes. Some

people claim that caffeine, chocolate, and

alcohol make their symptoms worse and either

avoid or limit them in their diet. Not smokingalso may help lessen the symptoms.



Pressure pulse treatment. The U.S. Food and DrugAdministration (FDA) recently approved a device for

Ménières disease that fits into the outer ear and deliversintermittent air pressure pulses to the middle ear. The airpressure pulses appear to act on endolymph fluid toprevent dizziness.

Surgery. Surgery may be recommended when all othertreatments have failed to relieve dizziness. Some surgicalprocedures are performed on the endolymphatic sac todecompress it. Another possible surgery is to cut thevestibular nerve, although this occurs less frequently.



Cognitive therapy. Cognitive therapy is a type of talk therapy that helps people focus on how they

interpret and react to life experiences. Some

people find that cognitive therapy helps themcope better with the unexpected nature of attacks and reduces their anxiety about future

attacks.



Injections. Injecting the antibiotic gentamicin intothe middle ear helps control vertigo but significantlyraises the risk of hearing loss because gentamicin

can damage the microscopic hair cells in the innerear that help us hear. Some doctors inject acorticosteroid instead, which often helps reducedizziness and has no risk of hearing loss.

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