Friday 6 December 2013

Ménière's Disease





Please note that the following is a general guideline only. For a full assessment, exclusion of any other underlying cause for your symptoms and an individualised treatment approach, you will need to be seen by a qualified specialist.





Definition

A disorder of the inner ear with intermittent episodes of vertigo, tinnitus and fluctuating sensorineural hearing loss


Epidemiology

Incidence: 4 per 100 000
Age:  onset 4th decade / uncommon in children 
Sex: M=F
Race: More in European decent 1/2500/ rare in africans
Familial: 20% have positive family Hx




AETIOLOGY

Primary Unknown. Theories are
1 autoimmune
2 subclinical HSV 1 infection
3 ischaemia of parts of the balance organ

Some of the known causes are
1 Known congenital anomalies of the balance organ
2 Trauma
3 Otosclerosis of the inner ear (rare condition)
4 Some know autoimmune conditions
5 Some known viral infections



PATHOPHYSIOLOGY


Understanding the pathophysiology helps understands the symptoms and treatment of this condition. 

The ears act as balance organs in space. This is similar to how two jet engines (balance organs) in either side of a plane allows the pilot (your brain) to fly steady. 

Misfiring of an engine makes it impossible for the pilot to fly straight. In a similar way transient misfiring of one balance organ leads to vertigo as it does not allow for the brain to adopt.

However complete loss of one jet engine will allow the pilot to fly straight with the existing engine.  In a similar way complete damage to the cochlea and balance organ will allow the brain to adopt.

Initially menier'rs disease causes transient damage or misfiring leading to vertigo. However longer term injuries lead burnout of the organ leading to permanent hearing loss though resolving the vertigo. 


The cause for Menier'rs is an abnormality in the production and flow of the endolymphatic fluid (fluid with in the cochlea and the balance organ)  This leads to distention of the endolymphatic space (a space within the cochlea) causing a sense of ear fulness and tinnitus. When enough endolymph builds up behind the obstruction, there may be sudden outflow across the obstruction toward the sac causing vertigo. Once the pressure is released symptoms tend to settle, usually over hours. 





CLINICAL

vertigo 
Usually commences with fullness in the ear. 
Acute attacks most commonly last 2-3 hours, unusual to last more than 1 day
Vertigo ceases spontaneously in 60% of patients in 2 years due to damage or burnout of the balance organ. 


Hearing loss and ear fulness
Occurs at the commencement of attacks of vertigo. Hearing loss is transient affecting only the lower frequencies at first and recovers after attacks. 
Overtime the hearing loss become a permanent hearing loss due to damage to the cochlea and balance organ. (this dame causes vertigo the cease)  

Tinnitus
Non-pulsatile, whistling or roaring.



Staging of the Disease (depending on the Clinical sy)


Stage 0
Prodromal stage
Intermittent sx of variable duration

Stage 1   (50% of patients)
Intermittent attacks of vertigo dominate
Hearing recovers between attacks
Tinnitus lessens (sometimes disappears) between attacks

Stage 2  (25% of patients)
Intermittent attacks of vertigo 
Hearing fluctuates between attacks but does not recover
Tinnitus lessens between attacks
Aural fullness varies

Stage 3  (25% of patients)
Intermittent attacks of vertigo lessen and may cease 
Hearing does not fluctuate and remains poor
Tinnitus constant - some people are able to adapt
Aural fullness may persist












1 comment:

  1. Special thanks to Dr Nalaka Mahendra De Silva. Good work.

    ReplyDelete